File:  [gforth] / gforth / look.fs
Revision 1.14: download - view: text, annotated - select for diffs
Sat Sep 23 15:06:01 2000 UTC (19 years, 6 months ago) by anton
Branches: MAIN
CVS tags: HEAD
updated copyright dates in many files (not in ec-related files)

    1: \ LOOK.FS      xt -> lfa                               22may93jaw
    2: 
    3: \ Copyright (C) 1995,1996,1997,2000 Free Software Foundation, Inc.
    4: 
    5: \ This file is part of Gforth.
    6: 
    7: \ Gforth is free software; you can redistribute it and/or
    8: \ modify it under the terms of the GNU General Public License
    9: \ as published by the Free Software Foundation; either version 2
   10: \ of the License, or (at your option) any later version.
   11: 
   12: \ This program is distributed in the hope that it will be useful,
   13: \ but WITHOUT ANY WARRANTY; without even the implied warranty of
   14: \ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   15: \ GNU General Public License for more details.
   16: 
   17: \ You should have received a copy of the GNU General Public License
   18: \ along with this program; if not, write to the Free Software
   19: \ Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
   20: 
   21: \ Look checks first if the word is a primitive. If yes then the
   22: \ vocabulary in the primitive area is beeing searched, meaning
   23: \ creating for each word a xt and comparing it...
   24: 
   25: \ If a word is no primitive look searches backwards to find the nfa.
   26: \ Problems: A compiled xt via compile, might be created with noname:
   27: \           a noname: leaves now a empty name field
   28: 
   29: decimal
   30: 
   31: \ look                                                  17may93jaw
   32: 
   33: \ rename to discover!!!
   34: 
   35: : (look)  ( xt startlfa -- lfa flag )
   36:         false swap
   37:         BEGIN @ dup
   38:         WHILE dup name>int
   39:               3 pick = IF nip dup THEN
   40:         REPEAT
   41:         drop nip
   42:         dup 0<> ;
   43: 
   44: 
   45: \ !!! nicht optimal!
   46: [IFUNDEF] look
   47: has? ec [IF]
   48: 
   49: has? rom 
   50: [IF]
   51: : look
   52:     dup [ unlock rom-dictionary area lock ] 
   53:     literal literal within
   54:     IF
   55: 	>head-noprim dup ?? <>
   56:     ELSE
   57: 	forth-wordlist @ (look)
   58:     THEN ;
   59: [ELSE]
   60: : look ( cfa -- lfa flag )
   61:     >head-noprim dup ??? <> ;
   62: [THEN]
   63: 
   64: [ELSE]
   65: 
   66: : PrimStart ['] true >head-noprim ;
   67: 
   68: : look ( cfa -- lfa flag )
   69:     dup in-dictionary?
   70:     IF
   71: 	>head-noprim dup ??? <>
   72:     ELSE
   73: 	PrimStart (look)
   74:     THEN ;
   75: 
   76: [THEN]
   77: [THEN]
   78: 
   79: : >head ( cfa -- nt|0 ) \ gforth to-head
   80:     \G tries to find the name token nt of the word represented by cfa;
   81:     \G returns 0 if it fails.  This word is not absolutely reliable,
   82:     \G it may give false positives and produce wrong nts.
   83:     look and ;
   84: 
   85: ' >head ALIAS >name \ gforth to-name
   86: \G old name of @code{>head}

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