6.3.3 Guile Initialization

The module configuration statement causes loading and initialization of the guile module:

module modname guile [init-script=script] \
                           [init-fun=function"]

Upon module initialization stage, the module attempts to load the file named script. The file is loaded using primitive-load-path call (see Loading in The Guile Reference Manual), i.e. it is searched in the Guile load path. The init-fun parameter supplies the name of the initialization function. This Scheme function returns virtual function tables for the module itself and for each database that uses this module. It must be declared as follows:

(define (function arg)
  …)

This function is called several times. First of all, it is called after script is loaded. This time it is given #f as its argument, and its return value is saved as a global function table. Then, it is called for each database statement that uses module modname (defined in the module statement above), e.g.:

database dbname modname …

This time, it is given dbname as its argument and its return is stored as the virtual function table for this particular database.

The following example function returns a complete virtual function table:

(define (my-smap-init arg)
  (list (cons "init" db-init)
        (cons "done" db-done)
        (cons "open" db-open)
        (cons "close" db-close)
        (cons "query" db-query)
        (cons "xform" db-xform)))