This is a processor for GNU
arguments. It provides an alternative, less declarative interface
(see The (ice-9 getopt-long) Module). Unlike
getopt-long, it supports repeated options and any number of
short and long names per option. Access it with:
(use-modules (srfi srfi-37))
SRFI-37 principally provides an
option type and the
args-fold function. To use the library, create a set of
option and use it as a specification for invoking
Here is an example of a simple argument processor for the typical ‘--version’ and ‘--help’ options, which returns a backwards list of files given on the command line:
(args-fold (cdr (program-arguments)) (let ((display-and-exit-proc (lambda (msg) (lambda (opt name arg loads) (display msg) (quit))))) (list (option '(#\v "version") #f #f (display-and-exit-proc "Foo version 42.0\n")) (option '(#\h "help") #f #f (display-and-exit-proc "Usage: foo scheme-file ...")))) (lambda (opt name arg loads) (error "Unrecognized option `~A'" name)) (lambda (op loads) (cons op loads)) '())
Return an object that specifies a single kind of program option.
names is a list of command-line option names, and should consist of
characters for traditional
getopt short options and strings for
getopt_long-style long options.
required-arg? and optional-arg? are mutually exclusive;
one or both must be
#f. If required-arg?, the option
must be followed by an argument on the command line, such as
‘--opt=value’ for long options, or an error will be signalled.
If optional-arg?, an argument will be taken if available.
processor is a procedure that takes at least 3 arguments, called
args-fold encounters the option: the containing option
object, the name used on the command line, and the argument given for
the option (or
#f if none). The rest of the arguments are
args-fold “seeds”, and the processor should return
seeds as well.
Return the specified field of opt, an option object, as
described above for
Process args, a list of program arguments such as that returned by
(cdr (program-arguments)), in order against options, a list
of option objects as described above. All functions called take the
“seeds”, or the last multiple-values as multiple arguments, starting
with seed …, and must return the new seeds. Return the
unrecognized-option-proc, which is like an option object’s
processor, for any options not found in options.
operand-proc with any items on the command line that are
not named options. This includes arguments after ‘--’. It is
called with the argument in question, as well as the seeds.