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[gforth] /
gforth /
look.fs
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1.27:
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Sat Mar 22 10:04:07 2003 UTC (21 years, 1 month ago) by
anton
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v0-6-2,
HEAD
added LATEST, replaced uses of LAST @ with uses of LATEST
renamed LASTXT to LATESTXT, and changed the uses
made >NAME the primary name for >HEAD
documentation changes
\ LOOK.FS xt -> lfa 22may93jaw
\ Copyright (C) 1995,1996,1997,2000,2003 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
\ vocabulary in the primitive area is beeing searched, meaning
\ creating for each word a xt and comparing it...
\ If a word is no primitive look searches backwards to find the nfa.
\ Problems: A compiled xt via compile, might be created with noname:
\ a noname: leaves now a empty name field
require stuff.fs
require environ.fs
decimal
\ look 17may93jaw
\ rename to discover!!!
: 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]
[ELSE]
: PrimStart ['] true >head-noprim ;
: prim>name ( xt -- nt|0 )
PrimStart search-name ;
: 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 ;
: >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 ;
' >name ALIAS >head \ gforth to-head
\G another name of @code{>name}
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