(C) 2000 - 2001 Guido Draheim

@see LGPL for licensedescription: this wordset implements a simple module-system. the basic module-system is based on the three words MODULE/END-MODULE/EXPORT - these three were present TEK' mforth, here the MPE' forth is used as an example for the naming scheme. This implementation has also mpe's EXPOSE-MODULE, and it has a serious form of mpe's REQUIRES under the name ALSO-MODULE which clarifies that the search-order is modified. Note also that pfe defines a REQUIRES in require-ext that works like INCLUDE-ONCE

create a new WORDLIST with the given name. It will also have an implicit hidden vocabulary just as well and all DEFINITIONS will go into that hidden wordlist. Therefore the old CURRENT is memorized on the cs-stack.

effectivly, CONTEXT[1] will have the wordlist-id of the public wordlist "name" and CONTEXT[0] will have the hidden wordlist contained in "name" - the hidden wordlist will always be known as HIDDEN' so that it can be re-referenced without need to use ALSO just to access a single definition from just another vocabulary. Note that HIDDEN' is defined immediate (a VOCABULARY' ) to modify the ORDER inside a colon definition.

 : MODULE
   CURRENT @ ( -- old-current )
   VOCABULARY
   ALSO LATEST NAME> EXECUTE ALSO DEFINITIONS
   C" HIDDEN'" $CREATE WORDLIST CONTEXT !
 ;
 

clean up the cs-stack from the last MODULE definition. Effectivly, MODULE definitions can be nested.

 : END-MODULE ( old-current )
   PREVIOUS PREVIOUS CURRENT ! 
 

the named word in the hidden dictionary (i.e. the wordlist referenced in CURRENT) is exported into the public wordlist of it (i.e. which is in this implementation CONTEXT[1]). The actual implemenation will create a DEFER-word in the public wordlist withits parameter area pointing to the cfa of the hidden implementation.

 : EXPORT
   CURRENT @ CONTEXT CELL+ @ CURRENT !
   DEFER CURRENT !
   LATEST COUNT CURRENT @ SEARCH-WORDLIST
   IF LATEST NAME> >BODY ! ELSE ABORT" can't find word to export" THEN
 ;
 

affects the search order, ALSO module-wid CONTEXT ! hidden'

 : EXPOSE-MODULE 
    ALSO S" HIDDEN'" 
    ' DUP VOC? ABORT?" is no vocabulary" >VOC 
    SEARCH-WORDLIST 0= IF " no hidden vocabulary found" THEN
    DUP VOC? ABORT?" hidden is no vocabulary" EXECUTE
 ;
 

affects the search-order, ALSO module-wid CONTEXT !

 : ALSO-MODULE
   ' DUP VOC? ABORT?" is no vocabulary" 
   ALSO EXECUTE
 ;