This file documents GNU AutoGen Version 5.9.
AutoGen copyright (C) 1992-2007 Bruce Korb AutoOpts copyright (C)
1992-2007 Bruce Korb snprintfv copyright (C) 1999-2000 Gary V. Vaughan
AutoGen is free software: you can redistribute it and/or modify it
under the terms of the GNU General Public License as published by the
Free Software Foundation, either version 3 of the License, or (at
your option) any later version.
AutoGen is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see .
The Automated Program Generator
*******************************
This file documents AutoGen version 5.9. It is a tool designed for
generating program files that contain repetitive text with varied
substitutions. This document is very long because it is intended as a
reference document. For a quick start example, *Note Example Usage::.
The AutoGen distribution includes the basic generator engine and
several add-on libraries and programs. Of the most general interest
would be Automated Option processing, *Note AutoOpts::, which also
includes stand-alone support for configuration file parsing, *Note
Features::. Please see the "Add-on packages for AutoGen" section for
additional programs and libraries associated with AutoGen.
This edition documents version 5.9, May 2008.
1 Introduction
**************
AutoGen is a tool designed for generating program files that contain
repetitive text with varied substitutions. Its goal is to simplify
the maintenance of programs that contain large amounts of repetitious
text. This is especially valuable if there are several blocks of
such text that must be kept synchronized in parallel tables.
One common example is the problem of maintaining the code required for
processing program options. Processing options requires a minimum of
four different constructs be kept in proper order in different places
in your program. You need at least:
1. The flag character in the flag string,
2. code to process the flag when it is encountered,
3. a global state variable or two, and
4. a line in the usage text.
You will need more things besides this if you choose to implement long
option names, rc/ini/config file processing, environment variables
and so on. All of this can be done mechanically; with the proper
templates and this program. In fact, it has already been done and
AutoGen itself uses it *Note AutoOpts::. For a simple example of
Automated Option processing, *Note Quick Start::. For a full list of
the Automated Option features, *Note Features::.
1.1 The Purpose of AutoGen
==========================
The idea of this program is to have a text file, a template if you
will, that contains the general text of the desired output file.
That file includes substitution expressions and sections of text that
are replicated under the control of separate definition files.
AutoGen was designed with the following features:
1. The definitions are completely separate from the template. By
completely isolating the definitions from the template it
greatly increases the flexibility of the template
implementation. A secondary goal is that a template user only
needs to specify those data that are necessary to describe his
application of a template.
2. Each datum in the definitions is named. Thus, the definitions
can be rearranged, augmented and become obsolete without it
being necessary to go back and clean up older definition files.
Reduce incompatibilities!
3. Every definition name defines an array of values, even when
there is only one entry. These arrays of values are used to
control the replication of sections of the template.
4. There are named collections of definitions. They form a nested
hierarchy. Associated values are collected and associated with
a group name. These associated data are used collectively in
sets of substitutions.
5. The template has special markers to indicate where substitutions
are required, much like the `${VAR}' construct in a shell `here
doc'. These markers are not fixed strings. They are specified
at the start of each template. Template designers know best
what fits into their syntax and can avoid marker conflicts.
We did this because it is burdensome and difficult to avoid
conflicts using either M4 tokenization or C preprocessor
substitution rules. It also makes it easier to specify
expressions that transform the value. Of course, our
expressions are less cryptic than the shell methods.
6. These same markers are used, in conjunction with enclosed
keywords, to indicate sections of text that are to be skipped
and for sections of text that are to be repeated. This is a
major improvement over using C preprocessing macros. With the C
preprocessor, you have no way of selecting output text because
it is an unvarying, mechanical substitution process.
7. Finally, we supply methods for carefully controlling the output.
Sometimes, it is just simply easier and clearer to compute some
text or a value in one context when its application needs to be
later. So, functions are available for saving text or values
for later use.
1.2 A Simple Example
====================
This is just one simple example that shows a few basic features. If
you are interested, you also may run "make check" with the `VERBOSE'
environment variable set and see a number of other examples in the
`agen5/test/testdir' directory.
Assume you have an enumeration of names and you wish to associate some
string with each name. Assume also, for the sake of this example,
that it is either too complex or too large to maintain easily by hand.
We will start by writing an abbreviated version of what the result is
supposed to be. We will use that to construct our output templates.
In a header file, `list.h', you define the enumeration and the global
array containing the associated strings:
typedef enum {
IDX_ALPHA,
IDX_BETA,
IDX_OMEGA } list_enum;
extern char const* az_name_list[ 3 ];
Then you also have `list.c' that defines the actual strings:
#include "list.h"
char const* az_name_list[] = {
"some alpha stuff",
"more beta stuff",
"final omega stuff" };
First, we will define the information that is unique for each
enumeration name/string pair. This would be placed in a file named,
`list.def', for example.
autogen definitions list;
list = { list_element = alpha;
list_info = "some alpha stuff"; };
list = { list_info = "more beta stuff";
list_element = beta; };
list = { list_element = omega;
list_info = "final omega stuff"; };
The `autogen definitions list;' entry defines the file as an AutoGen
definition file that uses a template named `list'. That is followed
by three `list' entries that define the associations between the
enumeration names and the strings. The order of the differently named
elements inside of list is unimportant. They are reversed inside of
the `beta' entry and the output is unaffected.
Now, to actually create the output, we need a template or two that
can be expanded into the files you want. In this program, we use a
single template that is capable of multiple output files. The
definitions above refer to a `list' template, so it would normally be
named, `list.tpl'.
It looks something like this. (For a full description, *Note
Template File::.)
[+ AutoGen5 template h c +]
[+ CASE (suffix) +][+
== h +]
typedef enum {[+
FOR list "," +]
IDX_[+ (string-upcase! (get "list_element")) +][+
ENDFOR list +] } list_enum;
extern char const* az_name_list[ [+ (count "list") +] ];
[+
== c +]
#include "list.h"
char const* az_name_list[] = {[+
FOR list "," +]
"[+list_info+]"[+
ENDFOR list +] };[+
ESAC +]
The `[+ AutoGen5 template h c +]' text tells AutoGen that this is an
AutoGen version 5 template file; that it is to be processed twice;
that the start macro marker is `[+'; and the end marker is `+]'. The
template will be processed first with a suffix value of `h' and then
with `c'. Normally, the suffix values are appended to the
`base-name' to create the output file name.
The `[+ == h +]' and `[+ == c +]' `CASE' selection clauses select
different text for the two different passes. In this example, the
output is nearly disjoint and could have been put in two separate
templates. However, sometimes there are common sections and this is
just an example.
The `[+FOR list "," +]' and `[+ ENDFOR list +]' clauses delimit a
block of text that will be repeated for every definition of `list'.
Inside of that block, the definition name-value pairs that are
members of each `list' are available for substitutions.
The remainder of the macros are expressions. Some of these contain
special expression functions that are dependent on AutoGen named
values; others are simply Scheme expressions, the result of which
will be inserted into the output text. Other expressions are names
of AutoGen values. These values will be inserted into the output
text. For example, `[+list_info+]' will result in the value
associated with the name `list_info' being inserted between the
double quotes and `(string-upcase! (get "list_element"))' will first
"get" the value associated with the name `list_element', then change
the case of all the letters to upper case. The result will be
inserted into the output document.
If you have compiled AutoGen, you can copy out the template and
definitions as described above and run `autogen list.def'. This will
produce exactly the hypothesized desired output.
One more point, too. Lets say you decided it was too much trouble to
figure out how to use AutoGen, so you created this enumeration and
string list with thousands of entries. Now, requirements have
changed and it has become necessary to map a string containing the
enumeration name into the enumeration number. With AutoGen, you just
alter the template to emit the table of names. It will be guaranteed
to be in the correct order, missing none of the entries. If you want
to do that by hand, well, good luck.
1.3 csh/zsh caveat
==================
AutoGen tries to use your normal shell so that you can supply shell
code in a manner you are accustomed to using. If, however, you use
csh or zsh, you cannot do this. Csh is sufficiently difficult to
program that it is unsupported. Zsh, though largely programmable,
also has some anomalies that make it incompatible with AutoGen usage.
Therefore, when invoking AutoGen from these environments, you must
be certain to set the SHELL environment variable to a Bourne-derived
shell, e.g., sh, ksh or bash.
Any shell you choose for your own scripts need to follow these basic
requirements:
1. It handles `trap $sig ":"' without output to standard out. This
is done when the server shell is first started. If your shell
does not handle this, then it may be able to by loading
functions from its start up files.
2. At the beginning of each scriptlet, the command `\\cd $PWD' is
inserted. This ensures that `cd' is not aliased to something
peculiar and each scriptlet starts life in the execution
directory.
3. At the end of each scriptlet, the command `echo mumble' is
appended. The program you use as a shell must emit the single
argument `mumble' on a line by itself.
1.4 A User's Perspective
========================
Alexandre wrote:
>
> I'd appreciate opinions from others about advantages/disadvantages of
> each of these macro packages.
I am using AutoGen in my pet project, and find one of its best points
to be that it separates the operational data from the implementation.
Indulge me for a few paragraphs, and all will be revealed: In the
manual, Bruce cites the example of maintaining command line flags
inside the source code; traditionally spreading usage information,
flag names, letters and processing across several functions (if not
files). Investing the time in writing a sort of boiler plate (a
template in AutoGen terminology) pays by moving all of the option
details (usage, flags names etc.) into a well structured table (a
definition file if you will), so that adding a new command line
option becomes a simple matter of adding a set of details to the
table.
So far so good! Of course, now that there is a template, writing all
of that tedious optargs processing and usage functions is no longer an
issue. Creating a table of the options needed for the new project and
running AutoGen generates all of the option processing code in C
automatically from just the tabular data. AutoGen in fact already
ships with such a template... AutoOpts.
One final consequence of the good separation in the design of AutoGen
is that it is retargetable to a greater extent. The
egcs/gcc/fixinc/inclhack.def can equally be used (with different
templates) to create a shell script (inclhack.sh) or a c program
(fixincl.c).
This is just the tip of the iceberg. AutoGen is far more powerful
than these examples might indicate, and has many other varied uses.
I am certain Bruce or I could supply you with many and varied
examples, and I would heartily recommend that you try it for your
project and see for yourself how it compares to m4.
As an aside, I would be interested to see whether someone might be
persuaded to rationalise autoconf with AutoGen in place of m4... Ben,
are you listening? autoconf-3.0! `kay? =)O|
Sincerely,
Gary V. Vaughan
2 Definitions File
******************
This chapter describes the syntax and semantics of the AutoGen
definition file. In order to instantiate a template, you normally
must provide a definitions file that identifies itself and contains
some value definitions. Consequently, we keep it very simple. For
"advanced" users, there are preprocessing directives, sparse arrays,
named indexes and comments that may be used as well.
The definitions file is used to associate values with names. Every
value is implicitly an array of values, even if there is only one
value. Values may be either simple strings or compound collections of
name-value pairs. An array may not contain both simple and compound
members. Fundamentally, it is as simple as:
prog-name = "autogen";
flag = {
name = templ_dirs;
value = L;
descrip = "Template search directory list";
};
For purposes of commenting and controlling the processing of the
definitions, C-style comments and most C preprocessing directives are
honored. The major exception is that the `#if' directive is ignored,
along with all following text through the matching `#endif'
directive. The C preprocessor is not actually invoked, so C macro
substitution is *not* performed.
2.1 The Identification Definition
=================================
The first definition in this file is used to identify it as a AutoGen
file. It consists of the two keywords, `autogen' and `definitions'
followed by the default template name and a terminating semi-colon
(`;'). That is:
AutoGen Definitions TEMPLATE-NAME;
Note that, other than the name TEMPLATE-NAME, the words `AutoGen' and
`Definitions' are searched for without case sensitivity. Most
lookups in this program are case insensitive.
Also, if the input contains more identification definitions, they
will be ignored. This is done so that you may include (*note
Directives::) other definition files without an identification
conflict.
AutoGen uses the name of the template to find the corresponding
template file. It searches for the file in the following way,
stopping when it finds the file:
1. It tries to open `./TEMPLATE-NAME'. If it fails,
2. it tries `./TEMPLATE-NAME.tpl'.
3. It searches for either of these files in the directories listed
in the templ-dirs command line option.
If AutoGen fails to find the template file in one of these places, it
prints an error message and exits.
2.2 Named Definitions
=====================
Any name may have multiple values associated with it in the definition
file. If there is more than one instance, the *only* way to expand
all of the copies of it is by using the FOR (*note FOR::) text
function on it, as described in the next chapter.
There are two kinds of definitions, `simple' and `compound'. They
are defined thus (*note Full Syntax::):
compound_name '=' '{' definition-list '}' ';'
simple_name '=' string ';'
no_text_name ';'
`No_text_name' is a simple definition with a shorthand empty string
value. The string values for definitions may be specified in any of
several formation rules.
2.2.1 Definition List
---------------------
`definition-list' is a list of definitions that may or may not
contain nested compound definitions. Any such definitions may *only*
be expanded within a `FOR' block iterating over the containing
compound definition. *Note FOR::.
Here is, again, the example definitions from the previous chapter,
with three additional name value pairs. Two with an empty value
assigned (FIRST and LAST), and a "global" GROUP_NAME.
autogen definitions list;
group_name = example;
list = { list_element = alpha; first;
list_info = "some alpha stuff"; };
list = { list_info = "more beta stuff";
list_element = beta; };
list = { list_element = omega; last;
list_info = "final omega stuff"; };
2.2.2 Double Quote String
-------------------------
The string follows the C-style escaping (`\', `\n', `\f', `\v',
etc.), plus octal character numbers specified as `\ooo'. The
difference from "C" is that the string may span multiple lines. Like
ANSI "C", a series of these strings, possibly intermixed with single
quote strings, will be concatenated together.
2.2.3 Single Quote String
-------------------------
This is similar to the shell single-quote string. However, escapes
`\' are honored before another escape, single quotes `'' and hash
characters `#'. This latter is done specifically to disambiguate
lines starting with a hash character inside of a quoted string. In
other words,
fumble = '
#endif
';
could be misinterpreted by the definitions scanner, whereas this
would not:
fumble = '
\#endif
';
As with the double quote string, a series of these, even intermixed
with double quote strings, will be concatenated together.
2.2.4 Shell Output String
-------------------------
This is assembled according to the same rules as the double quote
string, except that there is no concatenation of strings and the
resulting string is written to a shell server process. The
definition takes on the value of the output string.
NB The text is interpreted by a server shell. There may be left over
state from previous server shell processing. This scriptlet may also
leave state for subsequent processing. However, a `cd' to the
original directory is always issued before the new command is issued.
2.2.5 An Unquoted String
------------------------
A simple string that does not contain white space may be left
unquoted. The string must not contain any of the characters special
to the definition text (i.e., `"', `#', `'', `(', `)', `,', `;', `<',
`=', `>', `[', `]', ``', `{', or `}'). This list is subject to
change, but it will never contain underscore (`_'), period (`.'),
slash (`/'), colon (`:'), hyphen (`-') or backslash (`\\').
Basically, if the string looks like it is a normal DOS or UNIX file
or variable name, and it is not one of two keywords (`autogen' or
`definitions') then it is OK to not quote it, otherwise you should.
2.2.6 Scheme Result String
--------------------------
A scheme result string must begin with an open parenthesis `('. The
scheme expression will be evaluated by Guile and the value will be
the result. The AutoGen expression functions are *dis*abled at this
stage, so do not use them.
2.2.7 A Here String
-------------------
A `here string' is formed in much the same way as a shell here doc.
It is denoted with two less than characters(`<<') and, optionally, a
hyphen. This is followed by optional horizontal white space and an
ending marker-identifier. This marker must follow the syntax rules
for identifiers. Unlike the shell version, however, you must not
quote this marker.
The resulting string will start with the first character on the next
line and continue up to but not including the newline that precedes
the line that begins with the marker token. If a hyphen follows the
less than characters, then leading tabs will be stripped and the
terminating marker will be recognized even if preceded by tabs. No
backslash or any other kind of processing is done on this string.
The characters are copied directly into the result string.
Here are two examples:
str1 = <<- STR_END
$quotes = " ' `
STR_END;
str2 = << STR_END
$quotes = " ' `
STR_END;
STR_END;
The first string contains no new line characters. The first
character is the dollar sign, the last the back quote.
The second string contains one new line character. The first
character is the tab character preceding the dollar sign. The last
character is the semicolon after the `STR_END'. That `STR_END' does
not end the string because it is not at the beginning of the line.
In the preceding case, the leading tab was stripped.
2.2.8 Concatenated Strings
--------------------------
If single or double quote characters are used, then you also have the
option, a la ANSI-C syntax, of implicitly concatenating a series of
them together, with intervening white space ignored.
NB You *cannot* use directives to alter the string content. That is,
str = "fumble"
#ifdef LATER
"stumble"
#endif
;
will result in a syntax error. The preprocessing directives are not
carried out by the C preprocessor. However,
str = '"fumble\n"
#ifdef LATER
" stumble\n"
#endif
';
*Will* work. It will enclose the `#ifdef LATER' and `#endif' in the
string. But it may also wreak havoc with the definition processing
directives. The hash characters in the first column should be
disambiguated with an escape `\' or join them with previous lines:
`"fumble\n#ifdef LATER...'.
2.3 Assigning an Index to a Definition
======================================
In AutoGen, every name is implicitly an array of values. When
assigning values, they are usually implicitly assigned to the next
highest slot. They can also be specified explicitly:
mumble[9] = stumble;
mumble[0] = grumble;
If, subsequently, you assign a value to `mumble' without an index,
its index will be `10', not `1'. If indexes are specified, they must
not cause conflicts.
`#define'-d names may also be used for index values. This is
equivalent to the above:
#define FIRST 0
#define LAST 9
mumble[LAST] = stumble;
mumble[FIRST] = grumble;
All values in a range do *not* have to be filled in. If you leave
gaps, then you will have a sparse array. This is fine (*note FOR::).
You have your choice of iterating over all the defined values, or
iterating over a range of slots. This:
[+ FOR mumble +][+ ENDFOR +]
iterates over all and only the defined entries, whereas this:
[+ FOR mumble (for-by 1) +][+ ENDFOR +]
will iterate over all 10 "slots". Your template will likely have to
contain something like this:
[+ IF (exist? (sprintf "mumble[%d]" (for-index))) +]
or else "mumble" will have to be a compound value that, say, always
contains a "grumble" value:
[+ IF (exist? "grumble") +]
2.4 Dynamic Text
================
There are several methods for including dynamic content inside a
definitions file. Three of them are mentioned above (*Note
shell-generated:: and *note scheme-generated::) in the discussion of
string formation rules. Another method uses the `#shell' processing
directive. It will be discussed in the next section (*note
Directives::). Guile/Scheme may also be used to yield to create
definitions.
When the Scheme expression is preceded by a backslash and single
quote, then the expression is expected to be an alist of names and
values that will be used to create AutoGen definitions.
This method can be be used as follows:
\'( (name (value-expression))
(name2 (another-expr)) )
This is entirely equivalent to:
name = (value-expression);
name2 = (another-expr);
Under the covers, the expression gets handed off to a Guile function
named `alist->autogen-def' in an expression that looks like this:
(alist->autogen-def
( (name (value-expression)) (name2 (another-expr)) ) )
2.5 Controlling What Gets Processed
===================================
Definition processing directives can *only* be processed if the '#'
character is the first character on a line. Also, if you want a '#'
as the first character of a line in one of your string assignments,
you should either escape it by preceding it with a backslash `\', or
by embedding it in the string as in `"\n#"'.
All of the normal C preprocessing directives are recognized, though
several are ignored. There is also an additional `#shell' -
`#endshell' pair. Another minor difference is that AutoGen
directives must have the hash character (`#') in column 1.
The final tweak is that `#!' is treated as a comment line. Using
this feature, you can use: `#! /usr/local/bin/autogen' as the first
line of a definitions file, set the mode to executable and "run" the
definitions file as if it were a direct invocation of AutoGen. This
was done for its hack value.
The ignored directives are: `#ident', `#let', `#pragma', and `#if'.
Note that when ignoring the `#if' directive, all intervening text
through its matching `#endif' is also ignored, including the `#else'
clause.
The AutoGen directives that affect the processing of definitions are:
`#assert `shell-script` | (scheme-expr) | '
If the `shell-script' or `scheme-expr' do not yield `true'
valued results, autogen will be aborted. If `' or
nothing at all is provided, then this directive is ignored.
When writing the shell script, remember this is on a
preprocessing line. Multiple lines must be backslash continued
and the result is a single long line. Separate multiple
commands with semi-colons.
The result is `false' (and fails) if the result is empty, the
number zero, or a string that starts with the letters 'n' or 'f'
("no" or "false").
`#define name [ ]'
Will add the name to the define list as if it were a DEFINE
program argument. Its value will be the first non-whitespace
token following the name. Quotes are *not* processed.
After the definitions file has been processed, any remaining
entries in the define list will be added to the environment.
`#elif'
This must follow an `#if' otherwise it will generate an error.
It will be ignored.
`#else'
This must follow an `#if', `#ifdef' or `#ifndef'. If it follows
the `#if', then it will be ignored. Otherwise, it will change
the processing state to the reverse of what it was.
`#endif'
This must follow an `#if', `#ifdef' or `#ifndef'. In all cases,
this will resume normal processing of text.
`#endmac'
This terminates a "macdef", but must not ever be encountered
directly.
`#endshell'
Ends the text processed by a command shell into autogen
definitions.
`#error [ ]'
This directive will cause AutoGen to stop processing and exit
with a status of EXIT_FAILURE.
`#if [ ]'
`#if' expressions are not analyzed. *Everything* from here to
the matching `#endif' is skipped.
`#ifdef name-to-test'
The definitions that follow, up to the matching `#endif' will be
processed only if there is a corresponding `-Dname' command line
option or if a `#define' of that name has been previously
encountered.
`#ifndef name-to-test'
The definitions that follow, up to the matching `#endif' will be
processed only if there is *not* a corresponding `-Dname'
command line option or there was a canceling `-Uname' option.
`#include unadorned-file-name'
This directive will insert definitions from another file into
the current collection. If the file name is adorned with double
quotes or angle brackets (as in a C program), then the include
is ignored.
`#line'
Alters the current line number and/or file name. You may wish to
use this directive if you extract definition source from other
files. `getdefs' uses this mechanism so AutoGen will report the
correct file and approximate line number of any errors found in
extracted definitions.
`#macdef'
This is a new AT&T research preprocessing directive. Basically,
it is a multi-line #define that may include other preprocessing
directives.
`#option opt-name [ ]'
This directive will pass the option name and associated text to
the AutoOpts optionLoadLine routine (*note
libopts-optionLoadLine::). The option text may span multiple
lines by continuing them with a backslash. The
backslash/newline pair will be replaced with two space
characters. This directive may be used to set a search path for
locating template files For example, this:
#option templ-dirs $ENVVAR/dirname
will direct autogen to use the `ENVVAR' environment variable to
find a directory named `dirname' that (may) contain templates.
Since these directories are searched in most recently supplied
first order, search directories supplied in this way will be
searched before any supplied on the command line.
`#shell'
Invokes `$SHELL' or `/bin/sh' on a script that should generate
AutoGen definitions. It does this using the same server process
that handles the back-quoted ``' text. *CAUTION* let not your
`$SHELL' be `csh'.
`#undef name-to-undefine'
Will remove any entries from the define list that match the
undef name pattern.
2.6 Pre-defined Names
=====================
When AutoGen starts, it tries to determine several names from the
operating environment and put them into environment variables for use
in both `#ifdef' tests in the definitions files and in shell scripts
with environment variable tests. `__autogen__' is always defined.
For other names, AutoGen will first try to use the POSIX version of
the `sysinfo(2)' system call. Failing that, it will try for the POSIX
`uname(2)' call. If neither is available, then only "`__autogen__'"
will be inserted into the environment. In all cases, the associated
names are converted to lower case, surrounded by doubled underscores
and non-symbol characters are replaced with underscores.
With Solaris on a sparc platform, `sysinfo(2)' is available. The
following strings are used:
* `SI_SYSNAME' (e.g., "__sunos__")
* `SI_HOSTNAME' (e.g., "__ellen__")
* `SI_ARCHITECTURE' (e.g., "__sparc__")
* `SI_HW_PROVIDER' (e.g., "__sun_microsystems__")
* `SI_PLATFORM' (e.g., "__sun_ultra_5_10__")
* `SI_MACHINE' (e.g., "__sun4u__")
For Linux and other operating systems that only support the
`uname(2)' call, AutoGen will use these values:
* `sysname' (e.g., "__linux__")
* `machine' (e.g., "__i586__")
* `nodename' (e.g., "__bach__")
By testing these pre-defines in my definitions, you can select pieces
of the definitions without resorting to writing shell scripts that
parse the output of `uname(1)'. You can also segregate real C code
from autogen definitions by testing for "`__autogen__'".
#ifdef __bach__
location = home;
#else
location = work;
#endif
2.7 Commenting Your Definitions
===============================
The definitions file may contain C and C++ style comments.
/*
* This is a comment. It continues for several lines and closes
* when the characters '*' and '/' appear together.
*/
// this comment is a single line comment
2.8 What it all looks like.
===========================
This is an extended example:
autogen definitions `template-name';
/*
* This is a comment that describes what these
* definitions are all about.
*/
global = "value for a global text definition.";
/*
* Include a standard set of definitions
*/
#include standards.def
a_block = {
a_field;
a_subblock = {
sub_name = first;
sub_field = "sub value.";
};
#ifdef FEATURE
a_subblock = {
sub_name = second;
};
#endif
};
2.9 Finite State Machine Grammar
================================
The preprocessing directives and comments are not part of the
grammar. They are handled by the scanner/lexer. The following was
extracted directly from the generated defParse-fsm.c source file.
The "EVT:" is the token seen, the "STATE:" is the current state and
the entries in this table describe the next state and the action to
take. Invalid transitions were removed from the table.
dp_trans_table[ DP_STATE_CT ][ DP_EVENT_CT ] = {
/* STATE 0: DP_ST_INIT */
{ { DP_ST_NEED_DEF, NULL }, /* EVT: autogen */
{ DP_ST_INVALID, dp_do_invalid }, /* EVT: definitions */
{ DP_ST_INVALID, dp_do_invalid }, /* EVT: End-Of-File */
{ DP_ST_INVALID, dp_do_invalid }, /* EVT: var_name */
{ DP_ST_INVALID, dp_do_invalid }, /* EVT: other_name */
{ DP_ST_INVALID, dp_do_invalid }, /* EVT: string */
{ DP_ST_INVALID, dp_do_invalid }, /* EVT: here_string */
{ DP_ST_INVALID, dp_do_invalid }, /* EVT: number */
{ DP_ST_INVALID, dp_do_invalid }, /* EVT: ; */
{ DP_ST_INVALID, dp_do_invalid }, /* EVT: = */
{ DP_ST_INVALID, dp_do_invalid }, /* EVT: , */
{ DP_ST_INVALID, dp_do_invalid }, /* EVT: { */
{ DP_ST_INVALID, dp_do_invalid }, /* EVT: } */
{ DP_ST_INVALID, dp_do_invalid }, /* EVT: [ */
{ DP_ST_INVALID, dp_do_invalid } /* EVT: ] */
/* STATE 1: DP_ST_NEED_DEF */
{ { DP_ST_INVALID, dp_do_invalid }, /* EVT: autogen */
{ DP_ST_NEED_TPL, NULL }, /* EVT: definitions */
{ DP_ST_INVALID, dp_do_invalid }, /* EVT: End-Of-File */
{ DP_ST_INVALID, dp_do_invalid }, /* EVT: var_name */
{ DP_ST_INVALID, dp_do_invalid }, /* EVT: other_name */
{ DP_ST_INVALID, dp_do_invalid }, /* EVT: string */
{ DP_ST_INVALID, dp_do_invalid }, /* EVT: here_string */
{ DP_ST_INVALID, dp_do_invalid }, /* EVT: number */
{ DP_ST_INVALID, dp_do_invalid }, /* EVT: ; */
{ DP_ST_INVALID, dp_do_invalid }, /* EVT: = */
{ DP_ST_INVALID, dp_do_invalid }, /* EVT: , */
{ DP_ST_INVALID, dp_do_invalid }, /* EVT: { */
{ DP_ST_INVALID, dp_do_invalid }, /* EVT: } */
{ DP_ST_INVALID, dp_do_invalid }, /* EVT: [ */
{ DP_ST_INVALID, dp_do_invalid } /* EVT: ] */
/* STATE 2: DP_ST_NEED_TPL */
{ { DP_ST_INVALID, dp_do_invalid }, /* EVT: autogen */
{ DP_ST_INVALID, dp_do_invalid }, /* EVT: definitions */
{ DP_ST_INVALID, dp_do_invalid }, /* EVT: End-Of-File */
{ DP_ST_NEED_SEMI, dp_do_tpl_name }, /* EVT: var_name */
{ DP_ST_NEED_SEMI, dp_do_tpl_name }, /* EVT: other_name */
{ DP_ST_NEED_SEMI, dp_do_tpl_name }, /* EVT: string */
{ DP_ST_INVALID, dp_do_invalid }, /* EVT: here_string */
{ DP_ST_INVALID, dp_do_invalid }, /* EVT: number */
{ DP_ST_INVALID, dp_do_invalid }, /* EVT: ; */
{ DP_ST_INVALID, dp_do_invalid }, /* EVT: = */
{ DP_ST_INVALID, dp_do_invalid }, /* EVT: , */
{ DP_ST_INVALID, dp_do_invalid }, /* EVT: { */
{ DP_ST_INVALID, dp_do_invalid }, /* EVT: } */
{ DP_ST_INVALID, dp_do_invalid }, /* EVT: [ */
{ DP_ST_INVALID, dp_do_invalid } /* EVT: ] */
/* STATE 3: DP_ST_NEED_SEMI */
{ { DP_ST_INVALID, dp_do_invalid }, /* EVT: autogen */
{ DP_ST_INVALID, dp_do_invalid }, /* EVT: definitions */
{ DP_ST_INVALID, dp_do_invalid }, /* EVT: End-Of-File */
{ DP_ST_INVALID, dp_do_invalid }, /* EVT: var_name */
{ DP_ST_INVALID, dp_do_invalid }, /* EVT: other_name */
{ DP_ST_INVALID, dp_do_invalid }, /* EVT: string */
{ DP_ST_INVALID, dp_do_invalid }, /* EVT: here_string */
{ DP_ST_INVALID, dp_do_invalid }, /* EVT: number */
{ DP_ST_NEED_NAME, NULL }, /* EVT: ; */
{ DP_ST_INVALID, dp_do_invalid }, /* EVT: = */
{ DP_ST_INVALID, dp_do_invalid }, /* EVT: , */
{ DP_ST_INVALID, dp_do_invalid }, /* EVT: { */
{ DP_ST_INVALID, dp_do_invalid }, /* EVT: } */
{ DP_ST_INVALID, dp_do_invalid }, /* EVT: [ */
{ DP_ST_INVALID, dp_do_invalid } /* EVT: ] */
/* STATE 4: DP_ST_NEED_NAME */
{ { DP_ST_NEED_DEF, NULL }, /* EVT: autogen */
{ DP_ST_INVALID, dp_do_invalid }, /* EVT: definitions */
{ DP_ST_DONE, dp_do_need_name_end }, /* EVT: End-Of-File */
{ DP_ST_HAVE_NAME, dp_do_need_name_var_name }, /* EVT: var_name */
{ DP_ST_INVALID, dp_do_invalid }, /* EVT: other_name */
{ DP_ST_INVALID, dp_do_invalid }, /* EVT: string */
{ DP_ST_INVALID, dp_do_invalid }, /* EVT: here_string */
{ DP_ST_INVALID, dp_do_invalid }, /* EVT: number */
{ DP_ST_INVALID, dp_do_invalid }, /* EVT: ; */
{ DP_ST_INVALID, dp_do_invalid }, /* EVT: = */
{ DP_ST_INVALID, dp_do_invalid }, /* EVT: , */
{ DP_ST_INVALID, dp_do_invalid }, /* EVT: { */
{ DP_ST_HAVE_VALUE, dp_do_end_block }, /* EVT: } */
{ DP_ST_INVALID, dp_do_invalid }, /* EVT: [ */
{ DP_ST_INVALID, dp_do_invalid } /* EVT: ] */
/* STATE 5: DP_ST_HAVE_NAME */
{ { DP_ST_INVALID, dp_do_invalid }, /* EVT: autogen */
{ DP_ST_INVALID, dp_do_invalid }, /* EVT: definitions */
{ DP_ST_INVALID, dp_do_invalid }, /* EVT: End-Of-File */
{ DP_ST_INVALID, dp_do_invalid }, /* EVT: var_name */
{ DP_ST_INVALID, dp_do_invalid }, /* EVT: other_name */
{ DP_ST_INVALID, dp_do_invalid }, /* EVT: string */
{ DP_ST_INVALID, dp_do_invalid }, /* EVT: here_string */
{ DP_ST_INVALID, dp_do_invalid }, /* EVT: number */
{ DP_ST_NEED_NAME, dp_do_empty_val }, /* EVT: ; */
{ DP_ST_NEED_VALUE, dp_do_have_name_lit_eq }, /* EVT: = */
{ DP_ST_INVALID, dp_do_invalid }, /* EVT: , */
{ DP_ST_INVALID, dp_do_invalid }, /* EVT: { */
{ DP_ST_INVALID, dp_do_invalid }, /* EVT: } */
{ DP_ST_NEED_IDX, NULL }, /* EVT: [ */
{ DP_ST_INVALID, dp_do_invalid } /* EVT: ] */
/* STATE 6: DP_ST_NEED_VALUE */
{ { DP_ST_INVALID, dp_do_invalid }, /* EVT: autogen */
{ DP_ST_INVALID, dp_do_invalid }, /* EVT: definitions */
{ DP_ST_INVALID, dp_do_invalid }, /* EVT: End-Of-File */
{ DP_ST_HAVE_VALUE, dp_do_str_value }, /* EVT: var_name */
{ DP_ST_HAVE_VALUE, dp_do_str_value }, /* EVT: other_name */
{ DP_ST_HAVE_VALUE, dp_do_str_value }, /* EVT: string */
{ DP_ST_HAVE_VALUE, dp_do_str_value }, /* EVT: here_string */
{ DP_ST_HAVE_VALUE, dp_do_str_value }, /* EVT: number */
{ DP_ST_INVALID, dp_do_invalid }, /* EVT: ; */
{ DP_ST_INVALID, dp_do_invalid }, /* EVT: = */
{ DP_ST_INVALID, dp_do_invalid }, /* EVT: , */
{ DP_ST_NEED_NAME, dp_do_start_block }, /* EVT: { */
{ DP_ST_INVALID, dp_do_invalid }, /* EVT: } */
{ DP_ST_INVALID, dp_do_invalid }, /* EVT: [ */
{ DP_ST_INVALID, dp_do_invalid } /* EVT: ] */
/* STATE 7: DP_ST_NEED_IDX */
{ { DP_ST_INVALID, dp_do_invalid }, /* EVT: autogen */
{ DP_ST_INVALID, dp_do_invalid }, /* EVT: definitions */
{ DP_ST_INVALID, dp_do_invalid }, /* EVT: End-Of-File */
{ DP_ST_NEED_CBKT, dp_do_indexed_name }, /* EVT: var_name */
{ DP_ST_INVALID, dp_do_invalid }, /* EVT: other_name */
{ DP_ST_INVALID, dp_do_invalid }, /* EVT: string */
{ DP_ST_INVALID, dp_do_invalid }, /* EVT: here_string */
{ DP_ST_NEED_CBKT, dp_do_indexed_name }, /* EVT: number */
{ DP_ST_INVALID, dp_do_invalid }, /* EVT: ; */
{ DP_ST_INVALID, dp_do_invalid }, /* EVT: = */
{ DP_ST_INVALID, dp_do_invalid }, /* EVT: , */
{ DP_ST_INVALID, dp_do_invalid }, /* EVT: { */
{ DP_ST_INVALID, dp_do_invalid }, /* EVT: } */
{ DP_ST_INVALID, dp_do_invalid }, /* EVT: [ */
{ DP_ST_INVALID, dp_do_invalid } /* EVT: ] */
/* STATE 8: DP_ST_NEED_CBKT */
{ { DP_ST_INVALID, dp_do_invalid }, /* EVT: autogen */
{ DP_ST_INVALID, dp_do_invalid }, /* EVT: definitions */
{ DP_ST_INVALID, dp_do_invalid }, /* EVT: End-Of-File */
{ DP_ST_INVALID, dp_do_invalid }, /* EVT: var_name */
{ DP_ST_INVALID, dp_do_invalid }, /* EVT: other_name */
{ DP_ST_INVALID, dp_do_invalid }, /* EVT: string */
{ DP_ST_INVALID, dp_do_invalid }, /* EVT: here_string */
{ DP_ST_INVALID, dp_do_invalid }, /* EVT: number */
{ DP_ST_INVALID, dp_do_invalid }, /* EVT: ; */
{ DP_ST_INVALID, dp_do_invalid }, /* EVT: = */
{ DP_ST_INVALID, dp_do_invalid }, /* EVT: , */
{ DP_ST_INVALID, dp_do_invalid }, /* EVT: { */
{ DP_ST_INVALID, dp_do_invalid }, /* EVT: } */
{ DP_ST_INVALID, dp_do_invalid }, /* EVT: [ */
{ DP_ST_INDX_NAME, NULL } /* EVT: ] */
/* STATE 9: DP_ST_INDX_NAME */
{ { DP_ST_INVALID, dp_do_invalid }, /* EVT: autogen */
{ DP_ST_INVALID, dp_do_invalid }, /* EVT: definitions */
{ DP_ST_INVALID, dp_do_invalid }, /* EVT: End-Of-File */
{ DP_ST_INVALID, dp_do_invalid }, /* EVT: var_name */
{ DP_ST_INVALID, dp_do_invalid }, /* EVT: other_name */
{ DP_ST_INVALID, dp_do_invalid }, /* EVT: string */
{ DP_ST_INVALID, dp_do_invalid }, /* EVT: here_string */
{ DP_ST_INVALID, dp_do_invalid }, /* EVT: number */
{ DP_ST_NEED_NAME, dp_do_empty_val }, /* EVT: ; */
{ DP_ST_NEED_VALUE, NULL }, /* EVT: = */
{ DP_ST_INVALID, dp_do_invalid }, /* EVT: , */
{ DP_ST_INVALID, dp_do_invalid }, /* EVT: { */
{ DP_ST_INVALID, dp_do_invalid }, /* EVT: } */
{ DP_ST_INVALID, dp_do_invalid }, /* EVT: [ */
{ DP_ST_INVALID, dp_do_invalid } /* EVT: ] */
/* STATE 10: DP_ST_HAVE_VALUE */
{ { DP_ST_INVALID, dp_do_invalid }, /* EVT: autogen */
{ DP_ST_INVALID, dp_do_invalid }, /* EVT: definitions */
{ DP_ST_INVALID, dp_do_invalid }, /* EVT: End-Of-File */
{ DP_ST_INVALID, dp_do_invalid }, /* EVT: var_name */
{ DP_ST_INVALID, dp_do_invalid }, /* EVT: other_name */
{ DP_ST_INVALID, dp_do_invalid }, /* EVT: string */
{ DP_ST_INVALID, dp_do_invalid }, /* EVT: here_string */
{ DP_ST_INVALID, dp_do_invalid }, /* EVT: number */
{ DP_ST_NEED_NAME, NULL }, /* EVT: ; */
{ DP_ST_INVALID, dp_do_invalid }, /* EVT: = */
{ DP_ST_NEED_VALUE, dp_do_next_val }, /* EVT: , */
{ DP_ST_INVALID, dp_do_invalid }, /* EVT: { */
{ DP_ST_INVALID, dp_do_invalid }, /* EVT: } */
{ DP_ST_INVALID, dp_do_invalid }, /* EVT: [ */
{ DP_ST_INVALID, dp_do_invalid } /* EVT: ] */
2.10 Alternate Definition Forms
===============================
There are several methods for supplying data values for templates.
`no definitions'
It is entirely possible to write a template that does not depend
upon external definitions. Such a template would likely have an
unvarying output, but be convenient nonetheless because of an
external library of either AutoGen or Scheme functions, or both.
This can be accommodated by providing the `--override-tpl' and
`--no-definitions' options on the command line. *Note autogen
Invocation::.
`CGI'
AutoGen behaves as a CGI server if the definitions input is from
stdin and the environment variable `REQUEST_METHOD' is defined
and set to either "GET" or "POST", *Note AutoGen CGI::.
Obviously, all the values are constrained to strings because
there is no way to represent nested values.
`XML'
AutoGen comes with a program named, `xml2ag'. Its output can
either be redirected to a file for later use, or the program can
be used as an AutoGen wrapper. *Note xml2ag Invocation::.
The introductory template example (*note Example Usage::) can be
rewritten in XML as follows:
A more XML-normal form might look like this:
some alpha stuff
more beta stuff
final omega stuff
but you would have to change the template `list_info' references
into `text' references.
`standard AutoGen definitions'
Of course. :-)
3 Template File
***************
The AutoGen template file defines the content of the output text. It
is composed of two parts. The first part consists of a pseudo macro
invocation and commentary. It is followed by the template proper.
This pseudo macro is special. It is used to identify the file as a
AutoGen template file, fixing the starting and ending marks for the
macro invocations in the rest of the file, specifying the list of
suffixes to be generated by the template and, optionally, the shell
to use for processing shell commands embedded in the template.
AutoGen-ing a file consists of copying text from the template to the
output file until a start macro marker is found. The text from the
start marker to the end marker constitutes the macro text. AutoGen
macros may cause sections of the template to be skipped or processed
several times. The process continues until the end of the template is
reached. The process is repeated once for each suffix specified in
the pseudo macro.
This chapter describes the format of the AutoGen template macros and
the usage of the AutoGen native macros. Users may augment these by
defining their own macros, *Note DEFINE::.
3.1 Format of the Pseudo Macro
==============================
The pseudo macro is used to tell AutoGen how to process a template.
It tells autogen:
1. The start macro marker. It consists of punctuation characters
used to demarcate the start of a macro. It may be up to seven
characters long and must be the first non-whitespace characters
in the file.
It is generally a good idea to use some sort of opening bracket
in the starting macro and closing bracket in the ending macro
(e.g. `{', `(', `[', or even `<' in the starting macro). It
helps both visually and with editors capable of finding a
balancing parenthesis.
2. That start marker must be immediately followed by the identifier
strings "AutoGen5" and then "template", though capitalization is
not important.
The next several components may be intermingled:
3. Zero, one or more suffix specifications tell AutoGen how many
times to process the template file. No suffix specifications
mean that it is to be processed once and that the generated text
is to be written to `stdout'. The current suffix for each pass
can be determined with the `(suffix)' scheme function (*note SCM
suffix::).
The suffix specification consists of a sequence of POSIX
compliant file name characters and, optionally, an equal sign
and a file name formatting specification. That specification
may be either an ordinary sequence of file name characters with
zero, one or two "%s" formatting sequences in it, or else it may
be a Scheme expression that, when evaluated, produces such a
string. The Scheme result may not be empty. The two string
arguments allowed for that string are the base name of the
definition file, and the current suffix (that being the text to
the left of the equal sign). (Note: "POSIX compliant file name
characters" consist of alphanumerics plus the period (`.'),
hyphen (`-') and underscore (`_') characters.)
If the suffix begins with one of these three latter characters
and a formatting string is not specified, then that character is
presumed to be the suffix separator. Otherwise, without a
specified format string, a single period will separate the
suffix from the base name in constructing the output file name.
4. Comments: blank lines, lines starting with a hash mark [`#']),
and edit mode comments (text between pairs of `-*-' strings).
5. Some scheme expressions may be inserted in order to make
configuration changes before template processing begins.
"`before template processing begins'" means that there is no
current output file, no current suffix and, basically, none of
the AutoGen specific functions (*note AutoGen Functions::) may
be invoked.
It is used, for example, to allow the template writer to specify
the shell program that must be used to interpret the shell
commands in the template. It can have no effect on any shell
commands in the definitions file, as that file will have been
processed by the time the pseudo macro is interpreted.
(setenv "SHELL" "/bin/sh")
This is extremely useful to ensure that the shell used is the
one the template was written to use. By default, AutoGen
determines the shell to use by user preferences. Sometimes,
that can be the "csh", though.
The scheme expression can also be used to save a pre-existing
output file for later text extraction (*note SCM extract::).
(shellf "mv -f %1$s.c %1$s.sav" (base-name))
After these must come the end macro marker:
6. The punctuation characters used to demarcate the end of a macro.
Like the start marker, it must consist of seven or fewer
punctuation characters.
The ending macro marker has a few constraints on its content. Some of
them are just advisory, though. There is no special check for
advisory restrictions.
* It must not begin with a POSIX file name character (hyphen `-',
underscore `_' or period `.'), the backslash (`\') or open
parenthesis (`('). These are used to identify a suffix
specification, indicate Scheme code and trim white space.
* If it begins with an equal sign, then it must be separated from
any suffix specification by white space.
* The closing marker may not begin with an open parenthesis, as
that is used to enclose a scheme expression.
* It cannot begin with a backslash, as that is used to indicate
white space trimming after the end macro mark. If, in the body
of the template, you put the backslash character (`\') before
the end macro mark, then any white space characters after the
mark and through the newline character are trimmed.
* It is also helpful to avoid using the comment marker (`#'). It
might be seen as a comment within the pseudo macro.
* You should avoid using any of the quote characters double,
single or back-quote. It won't confuse AutoGen, but it might
well confuse you and/or your editor.
As an example, assume we want to use `[+' and `+]' as the start and
end macro markers, and we wish to produce a `.c' and a `.h' file,
then the pseudo macro might look something like this:
[+ AutoGen5 template -*- Mode: emacs-mode-of-choice -*-
h=chk-%s.h
c
# make sure we don't use csh:
(setenv "SHELL" "/bin/sh") +]
The template proper starts after the pseudo-macro. The starting
character is either the first non-whitespace character or the first
character after the newline that follows the end macro marker.
3.2 Naming a value
==================
When an AutoGen value is specified in a template, it is specified by
name. The name may be a simple name, or a compound name of several
components. Since each named value in AutoGen is implicitly an array
of one or more values, each component may have an index associated
with it.
It looks like this:
comp-name-1 . comp-name-2 [ 2 ]
Note that if there are multiple components to a name, each component
name is separated by a dot (`.'). Indexes follow a component name,
enclosed in square brackets (`[' and `]'). The index may be either
an integer or an integer-valued define name. The first component of
the name is searched for in the current definition level. If not
found, higher levels will be searched until either a value is found,
or there are no more definition levels. Subsequent components of the
name must be found within the context of the newly-current definition
level. Also, if the named value is prefixed by a dot (`.'), then the
value search is started in the current context only. No higher
levels are searched.
If someone rewrites this, I'll incorporate it. :-)
3.3 Macro Expression Syntax
===========================
AutoGen has two types of expressions: full expressions and basic
ones. A full AutoGen expression can appear by itself, or as the
argument to certain AutoGen built-in macros: CASE, IF, ELIF, INCLUDE,
INVOKE (explicit invocation, *note INVOKE::), and WHILE. If it
appears by itself, the result is inserted into the output. If it is
an argument to one of these macros, the macro code will act on it
sensibly.
You are constrained to basic expressions only when passing arguments
to user defined macros, *Note DEFINE::.
The syntax of a full AutoGen expression is:
[[ ] ] [ [ ]]
How the expression is evaluated depends upon the presence or absence
of the apply code and value name. The "value name" is the name of an
AutoGen defined value, or not. If it does not name such a value, the
expression result is generally the empty string. All expressions
must contain either a `value-name' or a `basic-expr'.
3.3.1 Apply Code
----------------
The "apply code" selected determines the method of evaluating the
expression. There are five apply codes, including the non-use of an
apply code.
`no apply code'
This is the most common expression type. Expressions of this
sort come in three flavors:
`'
The result is the value of `value-name', if defined.
Otherwise it is the empty string.
`'
The result of the basic expression is the result of the
full expression, *Note basic expression::.
` '
If there is a defined value for `value-name', then the
`basic-expr' is evaluated. Otherwise, the result is the
empty string.
`% '
If `value-name' is defined, use `basic-expr' as a format string
for sprintf. Then, if the `basic-expr' is either a back-quoted
string or a parenthesized expression, then hand the result to the
appropriate interpreter for further evaluation. Otherwise, for
single and double quote strings, the result is the result of the
sprintf operation. Naturally, if `value-name' is not defined,
the result is the empty string.
For example, assume that `fumble' had the string value,
`stumble':
[+ % fumble `printf '%%x\\n' $%s` +]
This would cause the shell to evaluate "`printf '%x\n'
$stumble'". Assuming that the shell variable `stumble' had a
numeric value, the expression result would be that number, in
hex. Note the need for doubled percent characters and
backslashes.
`? '
Two `basic-expr'-s are required. If the `value-name' is
defined, then the first `basic-expr-1' is evaluated, otherwise
`basic-expr-2' is.
`- '
Evaluate `basic-expr' only if `value-name' is not defined.
`?% '
This combines the functions of `?' and `%'. If `value-name' is
defined, it behaves exactly like `%', above, using
`basic-expr-1'. If not defined, then `basic-expr-2' is
evaluated.
For example, assume again that `fumble' had the string value,
`stumble':
[+ ?% fumble `cat $%s` `pwd` +]
This would cause the shell to evaluate "`cat $stumble'". If
`fumble' were not defined, then the result would be the name of
our current directory.
3.3.2 Basic Expression
----------------------
A basic expression can have one of the following forms:
`'STRING''
A single quoted string. Backslashes can be used to protect
single quotes (`''), hash characters (`#'), or backslashes (`\')
in the string. All other characters of STRING are output as-is
when the single quoted string is evaluated. Backslashes are
processed before the hash character for consistency with the
definition syntax. It is needed there to avoid preprocessing
conflicts.
`"STRING"'
A double quoted string. This is a cooked text string as in C,
except that they are not concatenated with adjacent strings.
Evaluating "`STRING'" will output STRING with all backslash
sequences interpreted.
``STRING`'
A back quoted string. When this expression is evaluated, STRING
is first interpreted as a cooked string (as in `"STRING"') and
evaluated as a shell expression by the AutoGen server shell.
This expression is replaced by the `stdout' output of the shell.
`(STRING)'
A parenthesized expression. It will be passed to the Guile
interpreter for evaluation and replaced by the resulting value.
If there is a Scheme error in this expression, Guile 1.4 and
Guile 1.6 will report the template line number where the error
occurs. Guile 1.7 has lost this capability.
Additionally, other than in the `%' and `?%' expressions, the
Guile expressions may be introduced with the Guile comment
character (`;') and you may put a series of Guile expressions
within a single macro. They will be implicitly evaluated as if
they were arguments to the `(begin ...)' expression. The result
will be the result of the last Guile expression evaluated.
3.4 AutoGen Scheme Functions
============================
AutoGen uses Guile to interpret Scheme expressions within AutoGen
macros. All of the normal Guile functions are available, plus several
extensions (*note Common Functions::) have been added to augment the
repertoire of string manipulation functions and manage the state of
AutoGen processing.
This section describes those functions that are specific to AutoGen.
Please take note that these AutoGen specific functions are not loaded
and thus not made available until after the command line options have
been processed and the AutoGen definitions have been loaded. They
may, of course, be used in Scheme functions that get defined at those
times, but they cannot be invoked.
3.4.1 `ag-function?' - test for function
----------------------------------------
Usage: (ag-function? ag-name)
return SCM_BOOL_T if a specified name is a user-defined AutoGen
macro, otherwise return SCM_BOOL_F.
Arguments:
ag-name - name of AutoGen macro
3.4.2 `base-name' - base output name
------------------------------------
Usage: (base-name)
Returns a string containing the base name of the output file(s).
Generally, this is also the base name of the definitions file.
This Scheme function takes no arguments.
3.4.3 `chdir' - Change current directory
----------------------------------------
Usage: (chdir dir)
Sets the current directory for AutoGen. Shell commands will run from
this directory as well. This is a wrapper around the Guile native
function. It returns its directory name argument and fails the
program on failure.
Arguments:
dir - new directory name
3.4.4 `count' - definition count
--------------------------------
Usage: (count ag-name)
Count the number of entries for a definition. The input argument
must be a string containing the name of the AutoGen values to be
counted. If there is no value associated with the name, the result
is an SCM immediate integer value of zero.
Arguments:
ag-name - name of AutoGen value
3.4.5 `def-file' - definitions file name
----------------------------------------
Usage: (def-file)
Get the name of the definitions file. Returns the name of the source
file containing the AutoGen definitions.
This Scheme function takes no arguments.
3.4.6 `def-file-line' - get a definition file+line number
---------------------------------------------------------
Usage: (def-file-line ag-name [ msg-fmt ])
Returns the file and line number of a AutoGen defined value, using
either the default format, "from %s line %d", or else the format you
supply. For example, if you want to insert a "C" language file-line
directive, you would supply the format "# %2$d \"%1$s\"", but that is
also already supplied with the scheme variable *Note SCM
c-file-line-fmt::. You may use it thus:
(def-file-line "ag-def-name" c-file-line-fmt)
It is also safe to use the formatting string, "%2$d". AutoGen uses
an argument vector version of printf: *Note snprintfv::.
Arguments:
ag-name - name of AutoGen value
msg-fmt - Optional - formatting for line message
3.4.7 `dne' - "Do Not Edit" warning
-----------------------------------
Usage: (dne prefix [ first_prefix ] [ optpfx ])
Generate a "DO NOT EDIT" or "EDIT WITH CARE" warning string. Which
depends on whether or not the `--writable' command line option was
set. The first argument is a per-line string prefix. The optional
second argument is a prefix for the first-line and, in read-only
mode, activates the editor hints.
-*- buffer-read-only: t -*- vi: set ro:
The warning string also includes information about the template used
to construct the file and the definitions used in its instantiation.
The optional third argument is used when the first argument is
actually an invocation option and the prefix arguments get shifted.
The first argument must be, specifically, "`-d'". That is used to
signify that the date stamp should not be inserted into the output.
Arguments:
prefix - string for starting each output line
first_prefix - Optional - for the first output line
optpfx - Optional - shifted prefix
3.4.8 `error' - display message and exit
----------------------------------------
Usage: (error message)
The argument is a string that printed out as part of an error
message. The message is formed from the formatting string:
DEFINITIONS ERROR in %s line %d for %s: %s\n
The first three arguments to this format are provided by the routine
and are: The name of the template file, the line within the template
where the error was found, and the current output file name.
After displaying the message, the current output file is removed and
autogen exits with the EXIT_FAILURE error code. IF, however, the
argument begins with the number 0 (zero), or the string is the empty
string, then processing continues with the next suffix.
Arguments:
message - message to display before exiting
3.4.9 `exist?' - test for value name
------------------------------------
Usage: (exist? ag-name)
return SCM_BOOL_T iff a specified name has an AutoGen value. The
name may include indexes and/or member names. All but the last
member name must be an aggregate definition. For example:
(exist? "foo[3].bar.baz")
will yield true if all of the following is true:
There is a member value of either group or string type named `baz'
for some group value `bar' that is a member of the `foo' group with
index `3'. There may be multiple entries of `bar' within `foo', only
one needs to contain a value for `baz'.
Arguments:
ag-name - name of AutoGen value
3.4.10 `find-file' - locate a file in the search path
-----------------------------------------------------
Usage: (find-file file-name [ suffix ])
AutoGen has a search path that it uses to locate template and
definition files. This function will search the same list for
`file-name', both with and without the `.suffix', if provided.
Arguments:
file-name - name of file with text
suffix - Optional - file suffix to try, too
3.4.11 `first-for?' - detect first iteration
--------------------------------------------
Usage: (first-for? [ for_var ])
Returns SCM_BOOL_T if the named FOR loop (or, if not named, the
current innermost loop) is on the first pass through the data.
Outside of any FOR loop, it returns SCM_UNDEFINED. *Note FOR::.
Arguments:
for_var - Optional - which for loop
3.4.12 `for-by' - set iteration step
------------------------------------
Usage: (for-by by)
This function records the "step by" information for an AutoGen FOR
function. Outside of the FOR macro itself, this function will emit
an error. *Note FOR::.
Arguments:
by - the iteration increment for the AutoGen FOR macro
3.4.13 `for-from' - set initial index
-------------------------------------
Usage: (for-from from)
This function records the initial index information for an AutoGen
FOR function. Outside of the FOR macro itself, this function will
emit an error. *Note FOR::.
Arguments:
from - the initial index for the AutoGen FOR macro
3.4.14 `for-index' - get current loop index
-------------------------------------------
Usage: (for-index [ for_var ])
Returns the current index for the named FOR loop. If not named, then
the index for the innermost loop. Outside of any FOR loop, it
returns SCM_UNDEFINED. *Note FOR::.
Arguments:
for_var - Optional - which for loop
3.4.15 `for-sep' - set loop separation string
---------------------------------------------
Usage: (for-sep separator)
This function records the separation string that is to be inserted
between each iteration of an AutoGen FOR function. This is often
nothing more than a comma. Outside of the FOR macro itself, this
function will emit an error.
Arguments:
separator - the text to insert between the output of each FOR
iteration
3.4.16 `for-to' - set ending index
----------------------------------
Usage: (for-to to)
This function records the terminating value information for an
AutoGen FOR function. Outside of the FOR macro itself, this function
will emit an error. *Note FOR::.
Arguments:
to - the final index for the AutoGen FOR macro
3.4.17 `get' - get named value
------------------------------
Usage: (get ag-name [ alt-val ])
Get the first string value associated with the name. It will either
return the associated string value (if the name resolves), the
alternate value (if one is provided), or else the empty string.
Arguments:
ag-name - name of AutoGen value
alt-val - Optional - value if not present
3.4.18 `get-c-name' - get named value, mapped to C name syntax
--------------------------------------------------------------
Usage: (get-c-name ag-name)
Get the first string value associated with the name. It will either
return the associated string value (if the name resolves), the
alternate value (if one is provided), or else the empty string. The
result is passed through "string->c-name!".
Arguments:
ag-name - name of AutoGen value
3.4.19 `get-down-name' - get lower cased named value, mapped to C name syntax
-----------------------------------------------------------------------------
Usage: (get-down-name ag-name)
Get the first string value associated with the name. It will either
return the associated string value (if the name resolves), the
alternate value (if one is provided), or else the empty string. The
result is passed through "string->c-name!" and "string->down-case!".
Arguments:
ag-name - name of AutoGen value
3.4.20 `get-up-name' - get upper cased named value, mapped to C name syntax
---------------------------------------------------------------------------
Usage: (get-up-name ag-name)
Get the first string value associated with the name. It will either
return the associated string value (if the name resolves), the
alternate value (if one is provided), or else the empty string. The
result is passed through "string->c-name!" and "string->up-case!".
Arguments:
ag-name - name of AutoGen value
3.4.21 `high-lim' - get highest value index
-------------------------------------------
Usage: (high-lim ag-name)
Returns the highest index associated with an array of definitions.
This is generally, but not necessarily, one less than the `count'
value. (The indexes may be specified, rendering a non-zero based or
sparse array of values.)
This is very useful for specifying the size of a zero-based array of
values where not all values are present. For example:
tMyStruct myVals[ [+ (+ 1 (high-lim "my-val-list")) +] ];
Arguments:
ag-name - name of AutoGen value
3.4.22 `last-for?' - detect last iteration
------------------------------------------
Usage: (last-for? [ for_var ])
Returns SCM_BOOL_T if the named FOR loop (or, if not named, the
current innermost loop) is on the last pass through the data.
Outside of any FOR loop, it returns SCM_UNDEFINED. *Note FOR::.
Arguments:
for_var - Optional - which for loop
3.4.23 `len' - get count of values
----------------------------------
Usage: (len ag-name)
If the named object is a group definition, then "len" is the same as
"count". Otherwise, if it is one or more text definitions, then it
is the sum of their string lengths. If it is a single text
definition, then it is equivalent to `(string-length (get
"ag-name"))'.
Arguments:
ag-name - name of AutoGen value
3.4.24 `low-lim' - get lowest value index
-----------------------------------------
Usage: (low-lim ag-name)
Returns the lowest index associated with an array of definitions.
Arguments:
ag-name - name of AutoGen value
3.4.25 `make-header-guard' - make self-inclusion guard
------------------------------------------------------
Usage: (make-header-guard name)
This function will create a `#ifndef'/`#define' sequence for
protecting a header from multiple evaluation. It will also set the
Scheme variable `header-file' to the name of the file being protected
and it will set `header-guard' to the name of the `#define' being
used to protect it. It is expected that this will be used as follows:
[+ (make-header-guard "group_name") +]
...
#endif /* [+ (. header-guard) +] */
#include "[+ (. header-file) +]"
The `#define' name is composed as follows:
1. The first element is the string argument and a separating
underscore.
2. That is followed by the name of the header file with illegal
characters mapped to underscores.
3. The end of the name is always, "`_GUARD'".
4. Finally, the entire string is mapped to upper case.
The final `#define' name is stored in an SCM symbol named
`header-guard'. Consequently, the concluding `#endif' for the file
should read something like:
#endif /* [+ (. header-guard) +] */
The name of the header file (the current output file) is also stored
in an SCM symbol, `header-file'. Therefore, if you are also
generating a C file that uses the previously generated header file,
you can put this into that generated file:
#include "[+ (. header-file) +]"
Obviously, if you are going to produce more than one header file from
a particular template, you will need to be careful how these SCM
symbols get handled.
Arguments:
name - header group name
3.4.26 `match-value?' - test for matching value
-----------------------------------------------
Usage: (match-value? op ag-name test-str)
This function answers the question, "Is there an AutoGen value named
`ag-name' with a value that matches the pattern `test-str' using the
match function `op'?" Return SCM_BOOL_T iff at least one occurrence
of the specified name has such a value. The operator can be any
function that takes two string arguments and yields a boolean. It is
expected that you will use one of the string matching functions
provided by AutoGen.
The value name must follow the same rules as the `ag-name' argument
for `exist?' (*note SCM exist?::).
Arguments:
op - boolean result operator
ag-name - name of AutoGen value
test-str - string to test against
3.4.27 `out-delete' - delete current output file
------------------------------------------------
Usage: (out-delete)
Remove the current output file. Cease processing the template for
the current suffix. It is an error if there are `push'-ed output
files. Use the `(error "0")' scheme function instead. *Note output
controls::.
This Scheme function takes no arguments.
3.4.28 `out-depth' - output file stack depth
--------------------------------------------
Usage: (out-depth)
Returns the depth of the output file stack. *Note output controls::.
This Scheme function takes no arguments.
3.4.29 `out-emit-suspended' - emit the text of suspended output
---------------------------------------------------------------
Usage: (out-emit-suspended suspName)
This function is equivalent to `(begin (out-resume ) (out-pop
#t))'
Arguments:
suspName - A name tag of suspended output
3.4.30 `out-line' - output file line number
-------------------------------------------
Usage: (out-line)
Returns the current line number of the output file. It rewinds and
reads the file to count newlines.
This Scheme function takes no arguments.
3.4.31 `out-move' - change name of output file
----------------------------------------------
Usage: (out-move new-name)
Rename current output file. *Note output controls::. Please note:
changing the name will not save a temporary file from being deleted.
It may, however, be used on the root output file.
Arguments:
new-name - new name for the current output file
3.4.32 `out-name' - current output file name
--------------------------------------------
Usage: (out-name)
Returns the name of the current output file. If the current file is
a temporary, unnamed file, then it will scan up the chain until a
real output file name is found. *Note output controls::.
This Scheme function takes no arguments.
3.4.33 `out-pop' - close current output file
--------------------------------------------
Usage: (out-pop [ disp ])
If there has been a `push' on the output, then close that file and go
back to the previously open file. It is an error if there has not
been a `push'. *Note output controls::.
If there is no argument, no further action is taken. Otherwise, the
argument should be `#t' and the contents of the file are returned by
the function.
Arguments:
disp - Optional - return contents of the file
3.4.34 `out-push-add' - append output to file
---------------------------------------------
Usage: (out-push-add file-name)
Identical to `push-new', except the contents are *not* purged, but
appended to. *Note output controls::.
Arguments:
file-name - name of the file to append text to
3.4.35 `out-push-new' - purge and create output file
----------------------------------------------------
Usage: (out-push-new [ file-name ])
Leave the current output file open, but purge and create a new file
that will remain open until a `pop' `delete' or `switch' closes it.
The file name is optional and, if omitted, the output will be sent to
a temporary file that will be deleted when it is closed. *Note
output controls::.
Arguments:
file-name - Optional - name of the file to create
3.4.36 `out-resume' - resume suspended output file
--------------------------------------------------
Usage: (out-resume suspName)
If there has been a suspended output, then make that output descriptor
current again. That output must have been suspended with the same tag
name given to this routine as its argument.
Arguments:
suspName - A name tag for reactivating
3.4.37 `out-suspend' - suspend current output file
--------------------------------------------------
Usage: (out-suspend suspName)
If there has been a `push' on the output, then set aside the output
descriptor for later reactiviation with `(out-resume "xxx")'. The
tag name need not reflect the name of the output file. In fact, the
output file may be an anonymous temporary file. You may also change
the tag every time you suspend output to a file, because the tag
names are forgotten as soon as the file has been "resumed".
Arguments:
suspName - A name tag for reactivating
3.4.38 `out-switch' - close and create new output
-------------------------------------------------
Usage: (out-switch file-name)
Switch output files - close current file and make the current file
pointer refer to the new file. This is equivalent to `out-pop'
followed by `out-push-new', except that you may not pop the base
level output file, but you may `switch' it. *Note output controls::.
Arguments:
file-name - name of the file to create
3.4.39 `set-option' - Set a command line option
-----------------------------------------------
Usage: (set-option opt)
The text argument must be an option name followed by any needed
option argument. Returns SCM_UNDEFINED.
Arguments:
opt - AutoGen option name + its argument
3.4.40 `set-writable' - Make the output file be writable
--------------------------------------------------------
Usage: (set-writable [ set? ])
This function will set the current output file to be writable (or
not). This is only effective if neither the `--writable' nor
`--not-writable' have been specified. This state is reset when the
current suffix's output is complete.
Arguments:
set? - Optional - boolean arg, false to make output non-writable
3.4.41 `stack' - make list of AutoGen values
--------------------------------------------
Usage: (stack ag-name)
Create a scheme list of all the strings that are associated with a
name. They must all be text values or we choke.
Arguments:
ag-name - AutoGen value name
3.4.42 `suffix' - get the current suffix
----------------------------------------
Usage: (suffix)
Returns the current active suffix (*note pseudo macro::).
This Scheme function takes no arguments.
3.4.43 `tpl-file' - get the template file name
----------------------------------------------
Usage: (tpl-file [ full_path ])
Returns the name of the current template file. If `#t' is passed in
as an argument, then the template file is hunted for in the template
search path. Otherwise, just the unadorned name.
Arguments:
full_path - Optional - include full path to file
3.4.44 `tpl-file-line' - get the template file+line number
----------------------------------------------------------
Usage: (tpl-file-line [ msg-fmt ])
Returns the file and line number of the current template macro using
either the default format, "from %s line %d", or else the format you
supply. For example, if you want to insert a "C" language file-line
directive, you would supply the format "# %2$d \"%1$s\"", but that is
also already supplied with the scheme variable *Note SCM
c-file-line-fmt::. You may use it thus:
(tpl-file-line c-file-line-fmt)
It is also safe to use the formatting string, "%2$d". AutoGen uses
an argument vector version of printf: *Note snprintfv::.
Arguments:
msg-fmt - Optional - formatting for line message
3.4.45 `autogen-version' - autogen version number
-------------------------------------------------
This is a symbol defining the current AutoGen version number string.
It was first defined in AutoGen-5.2.14. It is currently "5.9.5".
3.4.46 format file info as, "`#line nn "file"'"
-----------------------------------------------
This is a symbol that can easily be used with the functions *Note SCM
tpl-file-line::, and *Note SCM def-file-line::. These will emit C
program `#line' directives pointing to template and definitions text,
respectively.
3.5 Common Scheme Functions
===========================
This section describes a number of general purpose functions that make
the kind of string processing that AutoGen does a little easier.
Unlike the AutoGen specific functions (*note AutoGen Functions::),
these functions are available for direct use during definition load
time. The equality test (*note SCM =::) is "overloaded" to do string
equivalence comparisons. If you are looking for inequality, the
Scheme/Lisp way of spelling that is, "(not (= ...))".
3.5.1 `ag-fprintf' - format to autogen stream
---------------------------------------------
Usage: (ag-fprintf ag-diversion format [ format-arg ... ])
Format a string using arguments from the alist. Write to a specified
AutoGen diversion. That may be either a specified suspended output
stream (*note SCM out-suspend::) or an index into the output stack
(*note SCM out-push-new::). `(ag-fprintf 0 ...)' is equivalent to
`(emit (sprintf ...))', and `(ag-fprintf 1 ...)' sends output to the
most recently suspended output stream.
Arguments:
ag-diversion - AutoGen diversion name or number
format - formatting string
format-arg - Optional - list of arguments to formatting string
3.5.2 `agpl' - GNU Affero General Public License
------------------------------------------------
Usage: (agpl prog-name prefix)
Emit a string that contains the GNU Affero General Public License.
It takes two arguments: `prefix' contains the string to start each
output line, and `prog_name' contains the name of the program the
copyright is about.
Arguments:
prog-name - name of the program under the GPL
prefix - String for starting each output line
3.5.3 `bsd' - BSD Public License
--------------------------------
Usage: (bsd prog_name owner prefix)
Emit a string that contains the Free BSD Public License. It takes
three arguments: `prefix' contains the string to start each output
line. `owner' contains the copyright owner. `prog_name' contains
the name of the program the copyright is about.
Arguments:
prog_name - name of the program under the BSD
owner - Grantor of the BSD License
prefix - String for starting each output line
3.5.4 `c-string' - emit string for ANSI C
-----------------------------------------
Usage: (c-string string)
Reform a string so that, when printed, the C compiler will be able to
compile the data and construct a string that contains exactly what the
current string contains. Many non-printing characters are replaced
with escape sequences. Newlines are replaced with a backslash, an
`n', a closing quote, a newline, seven spaces and another re-opening
quote. The compiler will implicitly concatenate them. The reader
will see line breaks.
A K&R compiler will choke. Use `kr-string' for that compiler.
Arguments:
string - string to reformat
3.5.5 `emit' - emit the text for each argument
----------------------------------------------
Usage: (emit alist ...)
Walk the tree of arguments, displaying the values of displayable SCM
types.
Arguments:
alist - list of arguments to stringify and emit
3.5.6 `emit-string-table' - output a string table
-------------------------------------------------
Usage: (emit-string-table st-name)
Emit into the current output stream a `static char const' array named
`st-name' that will have `NUL' bytes between each inserted string.
Arguments:
st-name - the name of the array of characters
3.5.7 `error-source-line' - display of file & line
--------------------------------------------------
Usage: (error-source-line)
This function is only invoked just before Guile displays an error
message. It displays the file name and line number that triggered
the evaluation error. You should not need to invoke this routine
directly. Guile will do it automatically.
This Scheme function takes no arguments.
3.5.8 `extract' - extract text from another file
------------------------------------------------
Usage: (extract file-name marker-fmt [ caveat ] [ default ])
This function is used to help construct output files that may contain
text that is carried from one version of the output to the next.
The first two arguments are required, the second are optional:
* The `file-name' argument is used to name the file that contains
the demarcated text.
* The `marker-fmt' is a formatting string that is used to construct
the starting and ending demarcation strings. The sprintf
function is given the `marker-fmt' with two arguments. The
first is either "START" or "END". The second is either "DO NOT
CHANGE THIS COMMENT" or the optional `caveat' argument.
* `caveat' is presumed to be absent if it is the empty string
(`""'). If absent, "DO NOT CHANGE THIS COMMENT" is used as the
second string argument to the `marker-fmt'.
* When a `default' argument is supplied and no pre-existing text
is found, then this text will be inserted between the START and
END markers.
The resulting strings are presumed to be unique within the subject
file. As a simplified example:
[+ (extract "fname" "// %s - SOMETHING - %s" ""
"example default") +]
will result in the following text being inserted into the output:
// START - SOMETHING - DO NOT CHANGE THIS COMMENT
example default
// END - SOMETHING - DO NOT CHANGE THIS COMMENT
The "`example default'" string can then be carried forward to the
next generation of the output, *provided* the output is not named
"`fname'" and the old output is renamed to "`fname'" before
AutoGen-eration begins.
*NB:*
You can set aside previously generated source files inside the
pseudo macro with a Guile/scheme function, extract the text you
want to keep with this extract function. Just remember you
should delete it at the end, too. Here is an example from my
Finite State Machine generator:
[+ AutoGen5 Template -*- Mode: text -*-
h=%s-fsm.h c=%s-fsm.c
(shellf
"[ -f %1$s-fsm.h ] && mv -f %1$s-fsm.h .fsm.head
[ -f %1$s-fsm.c ] && mv -f %1$s-fsm.c .fsm.code" (base-name)) +]
This code will move the two previously produced output files to files
named ".fsm.head" and ".fsm.code". At the end of the 'c' output
processing, I delete them.
Arguments:
file-name - name of file with text
marker-fmt - format for marker text
caveat - Optional - warn about changing marker
default - Optional - default initial text
3.5.9 `format-arg-count' - count the args to a format
-----------------------------------------------------
Usage: (format-arg-count format)
Sometimes, it is useful to simply be able to figure out how many
arguments are required by a format string. For example, if you are
extracting a format string for the purpose of generating a macro to
invoke a printf-like function, you can run the formatting string
through this function to determine how many arguments to provide for
in the macro. e.g. for this extraction text:
/*=fumble bumble
* fmt: 'stumble %s: %d\n'
=*/
You may wish to generate a macro:
#define BUMBLE(a1,a2) printf_like(something,(a1),(a2))
You can do this by knowing that the format needs two arguments.
Arguments:
format - formatting string
3.5.10 `fprintf' - format to a file
-----------------------------------
Usage: (fprintf port format [ format-arg ... ])
Format a string using arguments from the alist. Write to a specified
port. The result will NOT appear in your output. Use this to print
information messages to a template user.
Arguments:
port - Guile-scheme output port
format - formatting string
format-arg - Optional - list of arguments to formatting string
3.5.11 `gperf' - perform a perfect hash function
------------------------------------------------
Usage: (gperf name str)
Perform the perfect hash on the input string. This is only useful if
you have previously created a gperf program with the `make-gperf'
function *Note SCM make-gperf::. The `name' you supply here must
match the name used to create the program and the string to hash must
be one of the strings supplied in the `make-gperf' string list. The
result will be a perfect hash index.
See the documentation for `gperf(1GNU)' for more details.
Arguments:
name - name of hash list
str - string to hash
3.5.12 `gperf-code' - emit the source of the generated gperf program
--------------------------------------------------------------------
Usage: (gperf-code st-name)
Returns the contents of the emitted code, suitable for inclusion in
another program. The interface contains the following elements:
`struct _index'
containg the fields: `{char const * name, int const id; };'
`_hash()'
This is the hashing function with local only scope (static).
`_find()'
This is the searching and validation function. The first
argument is the string to look up, the second is its length. It
returns a pointer to the corresponding `_index' entry.
Use this in your template as follows where "" was set to be
"`lookup'":
[+ (make-gperf "lookup" (join "\n" (stack "name_list")))
(gperf-code "lookup") +]
void my_fun(char * str) {
struct lookup_index * li = lookup_find(str, strlen(str));
if (li != NULL) printf("%s yields %d\n", str, li->idx);
Arguments:
st-name - the name of the gperf hash list
3.5.13 `gpl' - GNU General Public License
-----------------------------------------
Usage: (gpl prog-name prefix)
Emit a string that contains the GNU General Public License. It takes
two arguments: `prefix' contains the string to start each output
line, and `prog_name' contains the name of the program the copyright
is about.
Arguments:
prog-name - name of the program under the GPL
prefix - String for starting each output line
3.5.14 `hide-email' - convert eaddr to javascript
-------------------------------------------------
Usage: (hide-email display eaddr)
Hides an email address as a java scriptlett. The 'mailto:' tag and
the email address are coded bytes rather than plain text. They are
also broken up.
Arguments:
display - display text
eaddr - email address
3.5.15 `html-escape-encode' - encode html special characters
------------------------------------------------------------
Usage: (html-escape-encode str)
This function will replace replace the characters `'&'', `'<'' and
`'>'' characters with the HTML/XML escape-encoded strings (`"&"',
`"<"', and `">"', respectively).
Arguments:
str - string to make substitutions in
3.5.16 `in?' - test for string in list
--------------------------------------
Usage: (in? test-string string-list ...)
Return SCM_BOOL_T if the first argument string is found in one of the
entries in the second (list-of-strings) argument.
Arguments:
test-string - string to look for
string-list - list of strings to check
3.5.17 `join' - join string list with separator
-----------------------------------------------
Usage: (join separator list ...)
With the first argument as the separator string, joins together an
a-list of strings into one long string. The list may contain nested
lists, partly because you cannot always control that.
Arguments:
separator - string to insert between entries
list - list of strings to join
3.5.18 `kr-string' - emit string for K&R C
------------------------------------------
Usage: (kr-string string)
Reform a string so that, when printed, a K&R C compiler will be able
to compile the data and construct a string that contains exactly what
the current string contains. Many non-printing characters are
replaced with escape sequences. New-lines are replaced with a
backslash-n-backslash and newline sequence,
Arguments:
string - string to reformat
3.5.19 `lgpl' - GNU Library General Public License
--------------------------------------------------
Usage: (lgpl prog_name owner prefix)
Emit a string that contains the GNU Library General Public License.
It takes three arguments: `prefix' contains the string to start each
output line. `owner' contains the copyright owner. `prog_name'
contains the name of the program the copyright is about.
Arguments:
prog_name - name of the program under the LGPL
owner - Grantor of the LGPL
prefix - String for starting each output line
3.5.20 `license' - an arbitrary license
---------------------------------------
Usage: (license lic_name prog_name owner prefix)
Emit a string that contains the named license. The license text is
read from a file named, `lic_name'.lic, searching the standard
directories. The file contents are used as a format argument to
`printf'(3), with `prog_name' and `owner' as the two string
formatting arguments. Each output line is automatically prefixed
with the string `prefix'.
Arguments:
lic_name - file name of the license
prog_name - name of the licensed program or library
owner - Grantor of the License
prefix - String for starting each output line
3.5.21 `make-gperf' - build a perfect hash function program
-----------------------------------------------------------
Usage: (make-gperf name strings ...)
Build a program to perform perfect hashes of a known list of input
strings. This function produces no output, but prepares a program
named, `gperf_' for use by the gperf function *Note SCM gperf::.
This program will be obliterated as AutoGen exits. However, you may
incorporate the generated hashing function into your C program with
commands something like the following:
[+ (shellf "sed '/^int main(/,$d;/^#line/d' ${gpdir}/%s.c"
name ) +]
where `name' matches the name provided to this `make-perf' function.
`gpdir' is the variable used to store the name of the temporary
directory used to stash all the files.
Arguments:
name - name of hash list
strings - list of strings to hash
3.5.22 `makefile-script' - create makefile script
-------------------------------------------------
Usage: (makefile-script text)
This function will take ordinary shell script text and reformat it so
that it will work properly inside of a makefile shell script. Not
every shell construct can be supported; the intent is to have most
ordinary scripts work without much, if any, alteration.
The following transformations are performed on the source text:
1. Trailing whitespace on each line is stripped.
2. Except for the last line, the string, " ; \\" is appended to the
end of every line that does not end with a backslash, semi-colon,
conjunction operator or pipe. Note that this will mutilate
multi-line quoted strings, but `make' renders it impossible to
use multi-line constructs anyway.
3. If the line ends with a backslash, it is left alone.
4. If the line ends with one of the excepted operators, then a
space and backslash is added.
5. The dollar sign character is doubled, unless it immediately
precedes an opening parenthesis or the single character make
macros '*', '<', '@', '?' or '%'. Other single character make
macros that do not have enclosing parentheses will fail. For
shell usage of the "$@", "$?" and "$*" macros, you must enclose
them with curly braces, e.g., "${?}". The ksh construct
`$()' will not work. Though some `make's accept
`${var}' constructs, this function will assume it is for shell
interpretation and double the dollar character. You must use
`$(var)' for all `make' substitutions.
6. Double dollar signs are replaced by four before the next
character is examined.
7. Every line is prefixed with a tab, unless the first line already
starts with a tab.
8. The newline character on the last line, if present, is
suppressed.
9. Blank lines are stripped.
This function is intended to be used approximately as follows:
$(TARGET) : $(DEPENDENCIES)
<+ (out-push-new) +>
....mostly arbitrary shell script text....
<+ (makefile-script (out-pop #t)) +>
Arguments:
text - the text of the script
3.5.23 `max' - maximum value in list
------------------------------------
Usage: (max list ...)
Return the maximum value in the list
Arguments:
list - list of values. Strings are converted to numbers
3.5.24 `min' - minimum value in list
------------------------------------
Usage: (min list ...)
Return the minimum value in the list
Arguments:
list - list of values. Strings are converted to numbers
3.5.25 `prefix' - prefix lines with a string
--------------------------------------------
Usage: (prefix prefix text)
Prefix every line in the second string with the first string.
For example, if the first string is "# " and the second contains:
two
lines
The result string will contain:
# two
# lines
Arguments:
prefix - string to insert at start of each line
text - multi-line block of text
3.5.26 `printf' - format to stdout
----------------------------------
Usage: (printf format [ format-arg ... ])
Format a string using arguments from the alist. Write to the
standard out port. The result will NOT appear in your output. Use
this to print information messages to a template user. Use "(sprintf
...)" to add text to your document.
Arguments:
format - formatting string
format-arg - Optional - list of arguments to formatting string
3.5.27 `raw-shell-str' - single quote shell string
--------------------------------------------------
Usage: (raw-shell-str string)
Convert the text of the string into a singly quoted string that a
normal shell will process into the original string. (It will not do
macro expansion later, either.) Contained single quotes become
tripled, with the middle quote escaped with a backslash. Normal
shells will reconstitute the original string.
*Notice*: some shells will not correctly handle unusual non-printing
characters. This routine works for most reasonably conventional
ASCII strings.
Arguments:
string - string to transform
3.5.28 `shell' - invoke a shell script
--------------------------------------
Usage: (shell command)
Generate a string by writing the value to a server shell and reading
the output back in. The template programmer is responsible for
ensuring that it completes within 10 seconds. If it does not, the
server will be killed, the output tossed and a new server started.
Arguments:
command - shell command - the result value is stdout
3.5.29 `shell-str' - double quote shell string
----------------------------------------------
Usage: (shell-str string)
Convert the text of the string into a double quoted string that a
normal shell will process into the original string, almost. It will
add the escape character `\\' before two special characters to
accomplish this: the backslash `\\' and double quote `"'.
*NOTE*: some shells will not correctly handle unusual non-printing
characters. This routine works for most reasonably conventional
ASCII strings.
*WARNING*:
This function omits the extra backslash in front of a backslash,
however, if it is followed by either a backquote or a dollar sign.
It must do this because otherwise it would be impossible to protect
the dollar sign or backquote from shell evaluation. Consequently, it
is not possible to render the strings "\\$" or "\\`". The lesser of
two evils.
All others characters are copied directly into the output.
The `sub-shell-str' variation of this routine behaves identically,
except that the extra backslash is omitted in front of `"' instead of
``'. You have to think about it. I'm open to suggestions.
Meanwhile, the best way to document is with a detailed output example.
If the backslashes make it through the text processing correctly,
below you will see what happens with three example strings. The first
example string contains a list of quoted `foo's, the second is the
same with a single backslash before the quote characters and the last
is with two backslash escapes. Below each is the result of the
`raw-shell-str', `shell-str' and `sub-shell-str' functions.
foo[0] ''foo'' 'foo' "foo" `foo` $foo
raw-shell-str -> \'\''foo'\'\'' '\''foo'\'' "foo" `foo` $foo'
shell-str -> "''foo'' 'foo' \"foo\" `foo` $foo"
sub-shell-str -> `''foo'' 'foo' "foo" \`foo\` $foo`
foo[1] \'bar\' \"bar\" \`bar\` \$bar
raw-shell-str -> '\'\''bar\'\'' \"bar\" \`bar\` \$bar'
shell-str -> "\\'bar\\' \\\"bar\\\" \`bar\` \$bar"
sub-shell-str -> `\\'bar\\' \"bar\" \\\`bar\\\` \$bar`
foo[2] \\'BAZ\\' \\"BAZ\\" \\`BAZ\\` \\$BAZ
raw-shell-str -> '\\'\''BAZ\\'\'' \\"BAZ\\" \\`BAZ\\` \\$BAZ'
shell-str -> "\\\\'BAZ\\\\' \\\\\"BAZ\\\\\" \\\`BAZ\\\` \\\$BAZ"
sub-shell-str -> `\\\\'BAZ\\\\' \\\"BAZ\\\" \\\\\`BAZ\\\\\` \\\$BAZ`
There should be four, three, five and three backslashes for the four
examples on the last line, respectively. The next to last line should
have four, five, three and three backslashes. If this was not
accurately reproduced, take a look at the agen5/test/shell.test test.
Notice the backslashes in front of the dollar signs. It goes from
zero to one to three for the "cooked" string examples.
Arguments:
string - string to transform
3.5.30 `shellf' - format a string, run shell
--------------------------------------------
Usage: (shellf format [ format-arg ... ])
Format a string using arguments from the alist, then send the result
to the shell for interpretation.
Arguments:
format - formatting string
format-arg - Optional - list of arguments to formatting string
3.5.31 `sprintf' - format a string
----------------------------------
Usage: (sprintf format [ format-arg ... ])
Format a string using arguments from the alist.
Arguments:
format - formatting string
format-arg - Optional - list of arguments to formatting string
3.5.32 `string-capitalize' - capitalize a new string
----------------------------------------------------
Usage: (string-capitalize str)
Create a new SCM string containing the same text as the original,
only all the first letter of each word is upper cased and all other
letters are made lower case.
Arguments:
str - input string
3.5.33 `string-capitalize!' - capitalize a string
-------------------------------------------------
Usage: (string-capitalize! str)
capitalize all the words in an SCM string.
Arguments:
str - input/output string
3.5.34 `string-contains-eqv?' - caseless substring
--------------------------------------------------
Usage: (*=* text match)
string-contains-eqv?: Test to see if a string contains an equivalent
string. `equivalent' means the strings match, but without regard to
character case and certain characters are considered `equivalent'.
Viz., '-', '_' and '^' are equivalent.
Arguments:
text - text to test for pattern
match - pattern/substring to search for
3.5.35 `string-contains?' - substring match
-------------------------------------------
Usage: (*==* text match)
string-contains?: Test to see if a string contains a substring.
"strstr(3)" will find an address.
Arguments:
text - text to test for pattern
match - pattern/substring to search for
3.5.36 `string-downcase' - lower case a new string
--------------------------------------------------
Usage: (string-downcase str)
Create a new SCM string containing the same text as the original,
only all the upper case letters are changed to lower case.
Arguments:
str - input string
3.5.37 `string-downcase!' - make a string be lower case
-------------------------------------------------------
Usage: (string-downcase! str)
Change to lower case all the characters in an SCM string.
Arguments:
str - input/output string
3.5.38 `string-end-eqv-match?' - caseless regex ending
------------------------------------------------------
Usage: (*~ text match)
string-end-eqv-match?: Test to see if a string ends with a pattern.
Case is not significant.
Arguments:
text - text to test for pattern
match - pattern/substring to search for
3.5.39 `string-end-match?' - regex match end
--------------------------------------------
Usage: (*~~ text match)
string-end-match?: Test to see if a string ends with a pattern.
Case is significant.
Arguments:
text - text to test for pattern
match - pattern/substring to search for
3.5.40 `string-ends-eqv?' - caseless string ending
--------------------------------------------------
Usage: (*= text match)
string-ends-eqv?: Test to see if a string ends with an equivalent
string.
Arguments:
text - text to test for pattern
match - pattern/substring to search for
3.5.41 `string-ends-with?' - string ending
------------------------------------------
Usage: (*== text match)
string-ends-with?: Test to see if a string ends with a substring.
strcmp(3) returns zero for comparing the string ends.
Arguments:
text - text to test for pattern
match - pattern/substring to search for
3.5.42 `string-equals?' - string matching
-----------------------------------------
Usage: (== text match)
string-equals?: Test to see if two strings exactly match.
Arguments:
text - text to test for pattern
match - pattern/substring to search for
3.5.43 `string-eqv-match?' - caseless regex match
-------------------------------------------------
Usage: (~ text match)
string-eqv-match?: Test to see if a string fully matches a pattern.
Case is not significant, but any character equivalences must be
expressed in your regular expression.
Arguments:
text - text to test for pattern
match - pattern/substring to search for
3.5.44 `string-eqv?' - caseless string match
--------------------------------------------
Usage: (= text match)
string-eqv?: Test to see if two strings are equivalent.
`equivalent' means the strings match, but without regard to character
case and certain characters are considered `equivalent'. Viz., '-',
'_' and '^' are equivalent. If the arguments are not strings, then
the result of the numeric comparison is returned.
This is an overloaded operation. If the arguments are not both
strings, then the query is passed through to `scm_num_eq_p()'.
Arguments:
text - text to test for pattern
match - pattern/substring to search for
3.5.45 `string-has-eqv-match?' - caseless regex contains
--------------------------------------------------------
Usage: (*~* text match)
string-has-eqv-match?: Test to see if a string contains a pattern.
Case is not significant.
Arguments:
text - text to test for pattern
match - pattern/substring to search for
3.5.46 `string-has-match?' - contained regex match
--------------------------------------------------
Usage: (*~~* text match)
string-has-match?: Test to see if a string contains a pattern. Case
is significant.
Arguments:
text - text to test for pattern
match - pattern/substring to search for
3.5.47 `string-match?' - regex match
------------------------------------
Usage: (~~ text match)
string-match?: Test to see if a string fully matches a pattern.
Case is significant.
Arguments:
text - text to test for pattern
match - pattern/substring to search for
3.5.48 `string-start-eqv-match?' - caseless regex start
-------------------------------------------------------
Usage: (~* text match)
string-start-eqv-match?: Test to see if a string starts with a
pattern. Case is not significant.
Arguments:
text - text to test for pattern
match - pattern/substring to search for
3.5.49 `string-start-match?' - regex match start
------------------------------------------------
Usage: (~~* text match)
string-start-match?: Test to see if a string starts with a pattern.
Case is significant.
Arguments:
text - text to test for pattern
match - pattern/substring to search for
3.5.50 `string-starts-eqv?' - caseless string start
---------------------------------------------------
Usage: (=* text match)
string-starts-eqv?: Test to see if a string starts with an
equivalent string.
Arguments:
text - text to test for pattern
match - pattern/substring to search for
3.5.51 `string-starts-with?' - string starting
----------------------------------------------
Usage: (==* text match)
string-starts-with?: Test to see if a string starts with a substring.
Arguments:
text - text to test for pattern
match - pattern/substring to search for
3.5.52 `string-substitute' - multiple global replacements
---------------------------------------------------------
Usage: (string-substitute source match repl)
`match' and `repl' may be either a single string or a list of
strings. Either way, they must have the same structure and number of
elements. For example, to replace all less than and all greater than
characters, do something like this:
(string-substitute source
("&" "<" ">")
("&" "<" ">"))
Arguments:
source - string to transform
match - substring or substring list to be replaced
repl - replacement strings or substrings
3.5.53 `string-table-add' - Add an entry to a string table
----------------------------------------------------------
Usage: (string-table-add st-name str-val)
Check for a duplicate string and, if none, then insert a new string
into the string table. In all cases, returns the character index of
the beginning of the string in the table.
The returned index can be used in expressions like:
string_array +
that will yield the address of the first byte of the inserted string.
See the `strtable.test' AutoGen test for a usage example.
Arguments:
st-name - the name of the array of characters
str-val - the (possibly) new value to add
3.5.54 `string-table-add-ref' - Add an entry to a string table, get reference
-----------------------------------------------------------------------------
Usage: (string-table-add-ref st-name str-val)
Identical to string-table-add, except the value returned is the
string "st-name" '+' and the index returned by string-table-add.
Arguments:
st-name - the name of the array of characters
str-val - the (possibly) new value to add
3.5.55 `string-table-new' - create a string table
-------------------------------------------------
Usage: (string-table-new st-name)
This function will create an array of characters. The companion
functions, (*Note SCM string-table-add::, and *note SCM
emit-string-table::) will insert text and emit the populated table,
respectively.
With these functions, it should be much easier to construct structures
containing string offsets instead of string pointers. That can be
very useful when transmitting, storing or sharing data with different
address spaces.
Here is a brief example copied from the strtable.test test:
[+ (string-table-new "scribble")
(out-push-new)
(define ix 0)
(define ct 1) +][+
FOR str IN that was the week that was +][+
(set! ct (+ ct 1))
(set! ix (string-table-add "scribble" (get "str")))
+]
scribble + [+ (. ix) +],[+
ENDFOR +]
NULL };
[+ (out-suspend "main")
(emit-string-table "scribble")
(ag-fprintf 0 "\nchar const *ap[%d] = {" ct)
(out-resume "main")
(out-pop #t) +]
Some explanation:
I added the `(out-push-new)' because the string table text is
diverted into an output stream named, "scribble" and I want to have
the string table emitted before the string table references. The
string table references are also emitted inside the `FOR' loop. So,
when the loop is done, the current output is suspended under the
name, "main" and the "scribble" table is then emitted into the
primary output. (`emit-string-table' inserts its output directly
into the current output stream. It does not need to be the last
function in an AutoGen macro block.) Next I `ag-fprintf' the
array-of-pointer declaration directly into the current output.
Finally I restore the "main" output stream and `(out-pop #t)'-it into
the main output stream.
Here is the result. Note that duplicate strings are not repeated in
the string table:
static char const scribble[18] =
"that\0" "was\0" "the\0" "week\0";
char const *ap[7] = {
scribble + 0,
scribble + 5,
scribble + 9,
scribble + 13,
scribble + 0,
scribble + 5,
NULL };
These functions use the global name space `stt-*' in addition to the
function names.
Arguments:
st-name - the name of the array of characters
3.5.56 `string-table-size' - print the current size of a string table
---------------------------------------------------------------------
Usage: (string-table-size st-name)
Returns the current byte count of the string table.
Arguments:
st-name - the name of the array of characters
3.5.57 `string->c-name!' - map non-name chars to underscore
-----------------------------------------------------------
Usage: (string->c-name! str)
Change all the graphic characters that are invalid in a C name token
into underscores. Whitespace characters are ignored. Any other
character type (i.e. non-graphic and non-white) will cause a failure.
Arguments:
str - input/output string
3.5.58 `string-tr' - convert characters with new result
-------------------------------------------------------
Usage: (string-tr source match translation)
This is identical to `string-tr!', except that it does not over-write
the previous value.
Arguments:
source - string to transform
match - characters to be converted
translation - conversion list
3.5.59 `string-tr!' - convert characters
----------------------------------------
Usage: (string-tr! source match translation)
This is the same as the `tr(1)' program, except the string to
transform is the first argument. The second and third arguments are
used to construct mapping arrays for the transformation of the first
argument.
It is too bad this little program has so many different and
incompatible implementations!
Arguments:
source - string to transform
match - characters to be converted
translation - conversion list
3.5.60 `string-upcase' - upper case a new string
------------------------------------------------
Usage: (string-upcase str)
Create a new SCM string containing the same text as the original,
only all the lower case letters are changed to upper case.
Arguments:
str - input string
3.5.61 `string-upcase!' - make a string be upper case
-----------------------------------------------------
Usage: (string-upcase! str)
Change to upper case all the characters in an SCM string.
Arguments:
str - input/output string
3.5.62 `sub-shell-str' - back quoted (sub-)shell string
-------------------------------------------------------
Usage: (sub-shell-str string)
This function is substantially identical to `shell-str', except that
the quoting character is ``' and the "leave the escape alone"
character is `"'.
Arguments:
string - string to transform
3.5.63 `sum' - sum of values in list
------------------------------------
Usage: (sum list ...)
Compute the sum of the list of expressions.
Arguments:
list - list of values. Strings are converted to numbers
3.5.64 `version-compare' - compare two version numbers
------------------------------------------------------
Usage: (version-compare op v1 v2)
Converts v1 and v2 strings into 64 bit values and returns the result
of running 'op' on those values. It assumes that the version is a 1
to 4 part dot-separated series of numbers. Suffixes like, "5pre4" or
"5-pre4" will be interpreted as two numbers. The first number ("5"
in this case) will be decremented and the number after the "pre" will
be added to 0xC000. (Unless your platform is unable to support 64
bit integer arithmetic. Then it will be added to 0xC0.)
Consequently, these yield true:
(version-compare > "5.8.5" "5.8.5-pre4")
(version-compare > "5.8.5-pre10" "5.8.5-pre4")
Arguments:
op - comparison operator
v1 - first version
v2 - compared-to version
3.6 AutoGen Native Macros
=========================
This section describes the various AutoGen natively defined macros.
Unlike the Scheme functions, some of these macros are "block macros"
with a scope that extends through a terminating macro. Block macros
must not overlap. That is to say, a block macro started within the
scope of an encompassing block macro must have its matching end macro
appear before the encompassing block macro is either ended or
subdivided.
The block macros are these:
`CASE'
This macro has scope through the `ESAC' macro. The scope is
subdivided by `SELECT' macros. You must have at least one
`SELECT' macro.
`DEFINE'
This macro has scope through the `ENDDEF' macro. The defined
user macro can never be a block macro. This macro is extracted
from the template before the template is processed.
Consequently, you cannot select a definition based on context.
You can, however, place them all at the end of the file.
`FOR'
This macro has scope through the `ENDFOR' macro.
`IF'
This macro has scope through the `ENDIF' macro. The scope may
be subdivided by `ELIF' and `ELSE' macros. Obviously, there may
be only one `ELSE' macro and it must be the last of these
subdivisions.
`INCLUDE'
This macro has the scope of the included file. It is a block
macro in the sense that the included file must not contain any
incomplete block macros.
`WHILE'
This macro has scope through the `ENDWHILE' macro.
3.6.1 AutoGen Macro Syntax
--------------------------
The general syntax is:
[ { | } ] [ ... ]
The syntax for `' depends on the particular macro, but is
generally a full expression (*note expression syntax::). Here are
the exceptions to that general rule:
1. `INVOKE' macros, implicit or explicit, must be followed by a
list of name/string value pairs. The string values are simple
expressions, as described above.
That is, the `INVOKE' syntax is one of these two:
[ [ = ] ... ]
INVOKE [ [ = ] ... ]
2. AutoGen FOR macros must be in one of three forms:
FOR [ ]
FOR (...Scheme expression list)
FOR IN [ ... ]
where:
`'
must be a simple name.
`'
is inserted between copies of the enclosed block. Do not
try to use "IN" as your separator string. It won't work.
`'
is an entry in a list of strings. "`'" is assigned
each value from the "`IN'" list before expanding the `FOR'
block.
`(...Scheme expression list)'
is expected to contain one or more of the `for-from',
`for-to', `for-by', and `for-sep' functions. (*Note FOR::,
and *Note AutoGen Functions::)
The first two forms iterate over the `FOR' block if `' is
found in the AutoGen values. The last form will create the
AutoGen value named `'.
3. AutoGen `DEFINE' macros must be followed by a simple name.
Anything after that is ignored. Consequently, that "comment
space" may be used to document any named values the macro
expects to have set up as arguments. *Note DEFINE::.
4. The AutoGen `COMMENT', `ELSE', `ESAC' and the `END*' macros take
no arguments and ignore everything after the macro name (e.g.
see *Note COMMENT::)
3.6.2 CASE - Select one of several template blocks
--------------------------------------------------
The arguments are evaluated and converted to a string, if necessary.
A simple name will be interpreted as an AutoGen value name and its
value will be used by the `SELECT' macros (see the example below and
the expression evaluation function, *note EXPR::). The scope of the
macro is up to the matching `ESAC' macro. Within the scope of a
`CASE', this string is matched against case selection macros. There
are sixteen match macros that are derived from four different ways
matches may be performed, plus an "always true", "true if the AutoGen
value was found", and "true if no AutoGen value was found" matches.
The codes for the nineteen match macros are formed as follows:
1. Must the match start matching from the beginning of the string?
If not, then the match macro code starts with an asterisk (`*').
2. Must the match finish matching at the end of the string? If
not, then the match macro code ends with an asterisk (`*').
3. Is the match a pattern match or a string comparison? If a
comparison, use an equal sign (`='). If a pattern match, use a
tilde (`~').
4. Is the match case sensitive? If alphabetic case is important,
double the tilde or equal sign.
5. Do you need a default match when none of the others match? Use
a single asterisk (`*').
6. Do you need to distinguish between an empty string value and a
value that was not found? Use the non-existence test (`!E')
before testing a full match against an empty string (`== ''').
There is also an existence test (`+E'), more for symmetry than
for practical use.
For example:
[+ CASE +]
[+ ~~* "[Tt]est" +]reg exp must match at start, not at end
[+ == "TeSt" +]a full-string, case sensitive compare
[+ = "TEST" +]a full-string, case insensitive compare
[+ !E +]not exists - matches if no AutoGen value found
[+ == "" +]expression yielded a zero-length string
[+ +E +]exists - matches if there is any value result
[+ * +]always match - no testing
[+ ESAC +]
`' (*note expression syntax::) may be any expression,
including the use of apply-codes and value-names. If the expression
yields a number, it is converted to a decimal string.
These case selection codes have also been implemented as Scheme
expression functions using the same codes. They are documented in
this texi doc as "string-*?" predicates (*note Common Functions::).
3.6.3 COMMENT - A block of comment to be ignored
------------------------------------------------
This function can be specified by the user, but there will never be a
situation where it will be invoked at emit time. The macro is
actually removed from the internal representation.
If the native macro name code is `#', then the entire macro function
is treated as a comment and ignored.
[+ # say what you want, but no '+' before any ']' chars +]
3.6.4 DEBUG - Print debug message to trace output
-------------------------------------------------
If the tracing level is at "debug-message" or above (*note autogen
trace::), this macro prints a debug message to trace output. This
message is not evaluated. This macro can also be used to set useful
debugger breakpoints. By inserting [+DEBUG n+] into your template,
you can set a debugger breakpoint on the #n case element below (in
the AutoGen source) and step through the processing of interesting
parts of your template.
To be useful, you have to have access to the source tree where autogen
was built and the template being processed. The definitions are also
helpful, but not crucial. Please contact the author if you think you
might actually want to use this.
3.6.5 DEFINE - Define a user AutoGen macro
------------------------------------------
This function will define a new macro. You must provide a name for
the macro. You do not specify any arguments, though the invocation
may specify a set of name/value pairs that are to be active during the
processing of the macro.
[+ define foo +]
... macro body with macro functions ...
[+ enddef +]
... [+ foo bar='raw text' baz=<> +]
Once the macro has been defined, this new macro can be invoked by
specifying the macro name as the first token after the start macro
marker. Alternatively, you may make the invocation explicitly invoke
a defined macro by specifying `INVOKE' (*note INVOKE::) in the macro
invocation. If you do that, the macro name can be computed with an
expression that gets evaluated every time the INVOKE macro is
encountered.
Any remaining text in the macro invocation will be used to create new
name/value pairs that only persist for the duration of the processing
of the macro. The expressions are evaluated the same way basic
expressions are evaluated. *Note expression syntax::.
The resulting definitions are handled much like regular definitions,
except:
1. The values may not be compound. That is, they may not contain
nested name/value pairs.
2. The bindings go away when the macro is complete.
3. The name/value pairs are separated by whitespace instead of
semi-colons.
4. Sequences of strings are not concatenated.
*NB:* The macro is extracted from the template as the template is
scanned. You cannot conditionally define a macro by enclosing
it in an `IF'/`ENDIF' (*note IF::) macro pair. If you need to
dynamically select the format of a `DEFINE'd macro, then put the
flavors into separate template files that simply define macros.
`INCLUDE' (*note INCLUDE::) the appropriate template when you
have computed which you need.
Due to this, it is acceptable and even a good idea to place all the
`DEFINE' macros at the end of the template. That puts the main body
of the template at the beginning of the file.
3.6.6 ELIF - Alternate Conditional Template Block
-------------------------------------------------
This macro must only appear after an `IF' function, and before any
associated `ELSE' or `ENDIF' functions. It denotes the start of an
alternate template block for the `IF' function. Its expression
argument is evaluated as are the arguments to `IF'. For a complete
description *Note IF::.
3.6.7 ELSE - Alternate Template Block
-------------------------------------
This macro must only appear after an `IF' function, and before the
associated `ENDIF' function. It denotes the start of an alternate
template block for the `IF' function. For a complete description
*Note IF::.
3.6.8 ENDDEF - Ends a macro definition.
---------------------------------------
This macro ends the `DEFINE' function template block. For a complete
description *Note DEFINE::.
3.6.9 ENDFOR - Terminates the `FOR' function template block
-----------------------------------------------------------
This macro ends the `FOR' function template block. For a complete
description *Note FOR::.
3.6.10 ENDIF - Terminate the `IF' Template Block
------------------------------------------------
This macro ends the `IF' function template block. For a complete
description *Note IF::.
3.6.11 ENDWHILE - Terminate the `WHILE' Template Block
------------------------------------------------------
This macro ends the `WHILE' function template block. For a complete
description *Note WHILE::.
3.6.12 ESAC - Terminate the `CASE' Template Block
-------------------------------------------------
This macro ends the `CASE' function template block. For a complete
description, *Note CASE::.
3.6.13 EXPR - Evaluate and emit an Expression
---------------------------------------------
This macro does not have a name to cause it to be invoked explicitly,
though if a macro starts with one of the apply codes or one of the
simple expression markers, then an expression macro is inferred. The
result of the expression evaluation (*note expression syntax::) is
written to the current output.
3.6.14 FOR - Emit a template block multiple times
-------------------------------------------------
This macro has a slight variation on the standard syntax:
FOR [ ]