Node:Using Guile Modules, Next:Creating Guile Modules, Previous:General Information about Modules, Up:The Guile module system
To use a Guile module is to access either its public interface or a
custom interface (see General Information about Modules). Both
types of access are handled by the syntactic form
which accepts one or more interface specifications and, upon evaluation,
arranges for those interfaces to be available to the current module.
This process may include locating and loading code for a given module if
that code has not yet been loaded, following %load-path (see Build Config).
An interface specification has one of two forms. The first
variation is simply to name the module, in which case its public
interface is the one accessed. For example:
(use-modules (ice-9 popen))
Here, the interface specification is
(ice-9 popen), and the
result is that the current module now has access to
open-input-pipe, and so on (see Included Guile Modules).
Note in the previous example that if the current module had already
open-pipe, that definition would be overwritten by the
(ice-9 popen). For this reason (and others), there
is a second variation of interface specification that not only names a
module to be accessed, but also selects bindings from it and renames
them to suit the current module's needs. For example:
(use-modules ((ice-9 popen) :select ((open-pipe . pipe-open) close-pipe) :renamer (symbol-prefix-proc 'unixy:)))
Here, the interface specification is more complex than before, and the
result is that a custom interface with only two bindings is created and
subsequently accessed by the current module. The mapping of old to new
names is as follows:
(ice-9 popen) sees: current module sees: open-pipe unixy:pipe-open close-pipe unixy:close-pipe
This example also shows how to use the convenience procedure
|symbol-prefix-proc prefix-sym||Scheme Procedure|
|Return a procedure that prefixes its arg (a symbol) with prefix-sym.|
|use-modules spec ...||syntax|
Resolve each interface specification spec into an interface and
arrange for these to be accessible by the current module. The return
value is unspecified.
spec can be a list of symbols, in which case it names a module whose public interface is found and used.
spec can also be of the form:
(MODULE-NAME [:select SELECTION] [:renamer RENAMER])
in which case a custom interface is newly created and used.
module-name is a list of symbols, as above; selection is a
list of selection-specs; and renamer is a procedure that takes a
symbol and returns its new name. A selection-spec is either a symbol or
a pair of symbols
Signal error if module name is not resolvable.
Load the module |