[gforth] / gforth / look.fs  

gforth: gforth/look.fs

Diff for /gforth/look.fs between version 1.19 and 1.28

version 1.19, Fri Dec 13 21:20:39 2002 UTC version 1.28, Mon Dec 31 18:40:24 2007 UTC
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 \ LOOK.FS      xt -> lfa                               22may93jaw  \ LOOK.FS      xt -> lfa                               22may93jaw
   
 \ Copyright (C) 1995,1996,1997,2000 Free Software Foundation, Inc.  \ Copyright (C) 1995,1996,1997,2000,2003 Free Software Foundation, Inc.
   
 \ This file is part of Gforth.  \ This file is part of Gforth.
   
 \ Gforth is free software; you can redistribute it and/or  \ Gforth is free software; you can redistribute it and/or
 \ modify it under the terms of the GNU General Public License  \ modify it under the terms of the GNU General Public License
 \ as published by the Free Software Foundation; either version 2  \ as published by the Free Software Foundation, either version 3
 \ of the License, or (at your option) any later version.  \ of the License, or (at your option) any later version.
   
 \ This program is distributed in the hope that it will be useful,  \ This program is distributed in the hope that it will be useful,
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 \ GNU General Public License for more details.  \ GNU General Public License for more details.
   
 \ You should have received a copy of the GNU General Public License  \ You should have received a copy of the GNU General Public License
 \ along with this program; if not, write to the Free Software  \ along with this program. If not, see http://www.gnu.org/licenses/.
 \ 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
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         @          @
     then ;      then ;
   
 : (look)  ( xt startlfa -- lfa flag )  : search-name  ( xt startlfa -- nt|0 )
     swap decompile-prim false rot      \ look up name of primitive with code at xt
       swap
       >r false swap
     BEGIN      BEGIN
         @ dup          @ dup
     WHILE      WHILE
             dup name>int xt>threaded              dup name>int
             3 pick = IF              r@ = IF
                 nip dup                  nip dup
             THEN              THEN
     REPEAT      REPEAT
     drop nip      drop rdrop ;
     dup 0<> ;  
   
   : 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!  \ !!! nicht optimal!
 [IFUNDEF] look  [IFUNDEF] look
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 has? rom  has? rom
 [IF]  [IF]
 : look  : prim>name ( xt -- nt|0 )
       forth-wordlist @ search-name ;
   
   : look ( xt -- lfa flag )
     dup [ unlock rom-dictionary area lock ]      dup [ unlock rom-dictionary area lock ]
     literal literal within      literal literal within
     IF      IF
         >head-noprim dup ?? <>          >head-noprim dup ?? <>
     ELSE      ELSE
         forth-wordlist @ (look)          prim>name dup 0<>
     THEN ;      THEN ;
 [ELSE]  [ELSE]
 : look ( cfa -- lfa flag )  : look ( cfa -- lfa flag )
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 : PrimStart ['] true >head-noprim ;  : PrimStart ['] true >head-noprim ;
   
 : look ( cfa -- lfa flag )  : prim>name ( xt -- nt|0 )
       PrimStart search-name ;
   
   : look ( xt -- lfa flag )
     dup in-dictionary?      dup in-dictionary?
     IF      IF
         >head-noprim dup ??? <>          >head-noprim dup ??? <>
     ELSE      ELSE
         PrimStart (look)          prim>name dup 0<>
     THEN ;      THEN ;
   
 [THEN]  [THEN]
 [THEN]  [THEN]
   
 : >head ( cfa -- nt|0 ) \ gforth to-head  : threaded>name ( ca -- nt|0 )
     \G tries to find the name token nt of the word represented by cfa;      threaded>xt prim>name ;
     \G returns 0 if it fails.  This word is not absolutely reliable,  
     \G it may give false positives and produce wrong nts.  : >name ( xt -- nt|0 ) \ gforth to-name
       \G tries to find the name token @var{nt} of the word represented
       \G by @var{xt}; returns 0 if it fails.  This word is not
       \G absolutely reliable, it may give false positives and produce
       \G wrong nts.
     look and ;      look and ;
   
 ' >head ALIAS >name \ gforth to-name  ' >name ALIAS >head \ gforth to-head
 \G old name of @code{>head}  \G another name of @code{>name}

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  Added in v.1.28
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