6.3 Guile

Guile is an acronym for GNU’s Ubiquitous Intelligent Language for Extensions. It provides a Scheme interpreter conforming to the R5RS language specification and a number of convenience functions. For information about the language, refer to Revised(5) Report on the Algorithmic Language Scheme. For a detailed description of Guile and its features, see Overview in The Guile Reference Manual.

The guile module provides an interface to Guile which allows for writing Smap modules in Scheme. The module is loaded using the following configuration file statement:

module name guile [args]

Optional args are:

debug

Enable Guile debugging and stack traces.

nodebug

Disable Guile debugging and stack traces (default).

load-path=path

Append directories from path to the list of directories which should be searched for Scheme modules and libraries. The path must be a list of directory names, separated by colons.

This option modifies the value of Guile’s %load-path variable. See the section Configuration and Installation in the Guile Reference Manual.

init-script=script

Specifies the name of a Scheme source file that must be loaded in order to initialize the module. The file is looked up using ‘%load-path’ variable.

init-args

The init-args parameter supplies additional arguments to the module. They will be accessible to the script via the command-line function.

init-fun

This parameter specifies the name of a function that will be invoked to perform the initialization of the module and of particular databases. Default name is ‘init’. See Guile Initialization, for a description of initialization sequence.

Guile databases are declared using the following syntax:

database dbname modname [args] [cmdline]

where: dbname gives the name for this database and modname is the name given to Guile module in module statement (see above).

Optional args override global settings given in the module statement. The following options are understood: init-script, init-args, and init-fun. Their meaning is the same as for module statement (see above), except that they affect only this particular database.

Any additional arguments, referenced as cmdline above, are be passed to the Guile open-db callback function (see open-db).