Diff for /gforth/look.fs between versions 1.1 and 1.23

version 1.1, 1994/02/11 16:30:46 version 1.23, 2003/01/06 11:18:59
Line 1 Line 1
 \ LOOK.FS      xt -> lfa                               22may93jaw  \ LOOK.FS      xt -> lfa                               22may93jaw
   
   \ Copyright (C) 1995,1996,1997,2000 Free Software Foundation, Inc.
   
   \ This file is part of Gforth.
   
   \ Gforth is free software; you can redistribute it and/or
   \ modify it under the terms of the GNU General Public License
   \ as published by the Free Software Foundation; either version 2
   \ of the License, or (at your option) any later version.
   
   \ This program is distributed in the hope that it will be useful,
   \ but WITHOUT ANY WARRANTY; without even the implied warranty of
   \ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   \ GNU General Public License for more details.
   
   \ You should have received a copy of the GNU General Public License
   \ along with this program; if not, write to the Free Software
   \ Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111, USA.
   
 \ Look checks first if the word is a primitive. If yes then the  \ Look checks first if the word is a primitive. If yes then the
 \ vocabulary in the primitive area is beeing searched, meaning  \ vocabulary in the primitive area is beeing searched, meaning
 \ creating for each word a xt and comparing it...  \ creating for each word a xt and comparing it...
Line 8 Line 26
 \ Problems: A compiled xt via compile, might be created with noname:  \ Problems: A compiled xt via compile, might be created with noname:
 \           a noname: leaves now a empty name field  \           a noname: leaves now a empty name field
   
   require stuff.fs
   require environ.fs
   
 decimal  decimal
   
 \ >NAME PRIMSTART                                       22may93jaw  \ look                                                  17may93jaw
   
 \ : >name ( xt -- nfa )  \ rename to discover!!!
 \         BEGIN   1 chars -  
 \                 dup c@ 128 and  
 \         UNTIL ;  
   
 : PrimStart ['] true >name ;  : xt>threaded ( xt -- x )
   \G produces the threaded-code cell for the primitive xt
       threading-method 0= if
           @
       then ;
   
   : search-name  ( xt startlfa -- nt|0 )
       \ look up name of primitive with code at xt
       swap
       >r false swap
       BEGIN
           @ dup
       WHILE
               dup name>int
               r@ = IF
                   nip dup
               THEN
       REPEAT
       drop rdrop ;
   
   : threaded>xt ( ca -- xt|0 )
   \G For the code address ca of a primitive, find the xt (or 0).
       [IFDEF] decompile-prim
           decompile-prim
       [THEN]
        \ walk through the array of primitive CAs
       >r ['] noop begin
           dup @ while
               dup xt>threaded r@ = if
                   rdrop exit
               endif
               cell+
       repeat
       drop rdrop 0 ;
   
   \ !!! nicht optimal!
   [IFUNDEF] look
   has? ec [IF]
   
   has? rom 
   [IF]
   : prim>name ( xt -- nt|0 )
       forth-wordlist @ search-name ;
   
   : look ( xt -- lfa flag )
       dup [ unlock rom-dictionary area lock ] 
       literal literal within
       IF
           >head-noprim dup ?? <>
       ELSE
           prim>name dup 0<>
       THEN ;
   [ELSE]
   : look ( cfa -- lfa flag )
       >head-noprim dup ??? <> ;
   [THEN]
   
 \ look                                                  17may93jaw  [ELSE]
   
 : (look)  ( xt startlfa -- lfa flag )  : PrimStart ['] true >head-noprim ;
         false swap  
         BEGIN @ dup  
         WHILE dup cell+ name>  
               3 pick = IF nip dup THEN  
         REPEAT  
         drop nip  
         dup 0<> ;  
   
 : look ( cfa -- lfa flag )  : prim>name ( xt -- nt|0 )
         dup forthstart u<      PrimStart search-name ;
         IF PrimStart (look)  
         ELSE >name true THEN ;  : look ( xt -- lfa flag )
       dup in-dictionary?
       IF
           >head-noprim dup ??? <>
       ELSE
           prim>name dup 0<>
       THEN ;
   
   [THEN]
   [THEN]
   
   : threaded>name ( ca -- nt|0 )
       threaded>xt prim>name ;
   
   : >head ( cfa -- nt|0 ) \ gforth to-head
       \G tries to find the name token nt of the word represented by cfa;
       \G returns 0 if it fails.  This word is not absolutely reliable,
       \G it may give false positives and produce wrong nts.
       look and ;
   
   ' >head ALIAS >name \ gforth to-name
   \G old name of @code{>head}

Removed from v.1.1  
changed lines
  Added in v.1.23


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