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., 59 Temple Place, Suite 330, Boston, MA 02111, 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: require stuff.fs
30: require environ.fs
31:
32: decimal
33:
34: \ look 17may93jaw
35:
36: \ rename to discover!!!
37:
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:
44: : (look) ( xt startlfa -- lfa flag )
45: \ look up name of primitive with code at xt
46: swap
47: >r false swap
48: BEGIN
49: @ dup
50: WHILE
51: dup name>int
52: r@ = IF
53: nip dup
54: THEN
55: REPEAT
56: drop rdrop
57: dup 0<> ;
58:
59: : threaded>xt ( ca -- xt|0 )
60: \G For the code address ca of a primitive, find the xt (or 0).
61: [IFDEF] decompile-prim
62: decompile-prim
63: [THEN]
64: \ walk through the array of primitive CAs
65: >r ['] noop begin
66: dup @ while
67: dup xt>threaded r@ = if
68: rdrop exit
69: endif
70: cell+
71: repeat
72: drop rdrop 0 ;
73:
74: \ !!! nicht optimal!
75: [IFUNDEF] look
76: has? ec [IF]
77:
78: has? rom
79: [IF]
80: : prim>name ( xt -- nt flag )
81: forth-wordlist @ (look) ;
82:
83: : look
84: dup [ unlock rom-dictionary area lock ]
85: literal literal within
86: IF
87: >head-noprim dup ?? <>
88: ELSE
89: xt>threaded threaded>name
90: THEN ;
91: [ELSE]
92: : look ( cfa -- lfa flag )
93: >head-noprim dup ??? <> ;
94: [THEN]
95:
96: [ELSE]
97:
98: : PrimStart ['] true >head-noprim ;
99:
100: : prim>name ( xt -- lfa flag )
101: PrimStart (look) ;
102:
103: : look ( cfa -- lfa flag )
104: dup in-dictionary?
105: IF
106: >head-noprim dup ??? <>
107: ELSE
108: prim>name
109: THEN ;
110:
111: [THEN]
112: [THEN]
113:
114: : threaded>name ( ca -- lfa flag )
115: threaded>xt prim>name ;
116:
117: : >head ( cfa -- nt|0 ) \ gforth to-head
118: \G tries to find the name token nt of the word represented by cfa;
119: \G returns 0 if it fails. This word is not absolutely reliable,
120: \G it may give false positives and produce wrong nts.
121: look and ;
122:
123: ' >head ALIAS >name \ gforth to-name
124: \G old name of @code{>head}
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