Annotation of gforth/look.fs, revision 1.26
1.1 anton 1: \ LOOK.FS xt -> lfa 22may93jaw
2:
1.26 ! anton 3: \ Copyright (C) 1995,1996,1997,2000,2003 Free Software Foundation, Inc.
1.3 anton 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
1.15 anton 19: \ Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111, USA.
1.3 anton 20:
1.1 anton 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:
1.16 jwilke 29: require stuff.fs
30: require environ.fs
31:
1.1 anton 32: decimal
33:
1.8 jwilke 34: \ look 17may93jaw
1.1 anton 35:
1.8 jwilke 36: \ rename to discover!!!
1.1 anton 37:
1.18 anton 38: : xt>threaded ( xt -- x )
39: \G produces the threaded-code cell for the primitive xt
40: threading-method 0= if
41: @
42: then ;
43:
1.23 anton 44: : search-name ( xt startlfa -- nt|0 )
1.22 anton 45: \ look up name of primitive with code at xt
1.20 pazsan 46: swap
1.21 pazsan 47: >r false swap
1.17 anton 48: BEGIN
49: @ dup
50: WHILE
1.22 anton 51: dup name>int
1.21 pazsan 52: r@ = IF
1.17 anton 53: nip dup
54: THEN
55: REPEAT
1.23 anton 56: drop rdrop ;
1.1 anton 57:
1.22 anton 58: : threaded>xt ( ca -- xt|0 )
59: \G For the code address ca of a primitive, find the xt (or 0).
60: [IFDEF] decompile-prim
61: decompile-prim
62: [THEN]
63: \ walk through the array of primitive CAs
64: >r ['] noop begin
65: dup @ while
66: dup xt>threaded r@ = if
67: rdrop exit
68: endif
69: cell+
70: repeat
71: drop rdrop 0 ;
1.8 jwilke 72:
73: \ !!! nicht optimal!
74: [IFUNDEF] look
1.9 jwilke 75: has? ec [IF]
76:
1.10 jwilke 77: has? rom
1.8 jwilke 78: [IF]
1.23 anton 79: : prim>name ( xt -- nt|0 )
80: forth-wordlist @ search-name ;
1.22 anton 81:
1.23 anton 82: : look ( xt -- lfa flag )
1.9 jwilke 83: dup [ unlock rom-dictionary area lock ]
84: literal literal within
85: IF
1.13 anton 86: >head-noprim dup ?? <>
1.9 jwilke 87: ELSE
1.23 anton 88: prim>name dup 0<>
1.9 jwilke 89: THEN ;
90: [ELSE]
1.8 jwilke 91: : look ( cfa -- lfa flag )
1.13 anton 92: >head-noprim dup ??? <> ;
1.9 jwilke 93: [THEN]
1.8 jwilke 94:
95: [ELSE]
96:
1.13 anton 97: : PrimStart ['] true >head-noprim ;
1.8 jwilke 98:
1.23 anton 99: : prim>name ( xt -- nt|0 )
100: PrimStart search-name ;
1.22 anton 101:
1.23 anton 102: : look ( xt -- lfa flag )
1.12 anton 103: dup in-dictionary?
1.9 jwilke 104: IF
1.13 anton 105: >head-noprim dup ??? <>
1.12 anton 106: ELSE
1.23 anton 107: prim>name dup 0<>
1.9 jwilke 108: THEN ;
1.1 anton 109:
1.8 jwilke 110: [THEN]
111: [THEN]
1.22 anton 112:
1.23 anton 113: : threaded>name ( ca -- nt|0 )
1.22 anton 114: threaded>xt prim>name ;
1.13 anton 115:
116: : >head ( cfa -- nt|0 ) \ gforth to-head
117: \G tries to find the name token nt of the word represented by cfa;
118: \G returns 0 if it fails. This word is not absolutely reliable,
119: \G it may give false positives and produce wrong nts.
120: look and ;
121:
122: ' >head ALIAS >name \ gforth to-name
123: \G old name of @code{>head}
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