[gforth] / gforth / look.fs  

gforth: gforth/look.fs


1 : anton 1.1 \ LOOK.FS xt -> lfa 22may93jaw
2 :    
3 : anton 1.14 \ Copyright (C) 1995,1996,1997,2000 Free Software Foundation, Inc.
4 : anton 1.3
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 : anton 1.15 \ Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111, USA.
20 : anton 1.3
21 : anton 1.1 \ 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 : jwilke 1.16 require stuff.fs
30 :     require environ.fs
31 :    
32 : anton 1.1 decimal
33 :    
34 : jwilke 1.8 \ look 17may93jaw
35 : anton 1.1
36 : jwilke 1.8 \ rename to discover!!!
37 : anton 1.1
38 : anton 1.18 : 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 : anton 1.1 : (look) ( xt startlfa -- lfa flag )
45 : anton 1.22 \ look up name of primitive with code at xt
46 : pazsan 1.20 swap
47 : pazsan 1.21 >r false swap
48 : anton 1.17 BEGIN
49 :     @ dup
50 :     WHILE
51 : anton 1.22 dup name>int
52 : pazsan 1.21 r@ = IF
53 : anton 1.17 nip dup
54 :     THEN
55 :     REPEAT
56 : pazsan 1.21 drop rdrop
57 : anton 1.17 dup 0<> ;
58 : anton 1.1
59 : anton 1.22 : 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 : jwilke 1.8
74 :     \ !!! nicht optimal!
75 :     [IFUNDEF] look
76 : jwilke 1.9 has? ec [IF]
77 :    
78 : jwilke 1.10 has? rom
79 : jwilke 1.8 [IF]
80 : anton 1.22 : prim>name ( xt -- nt flag )
81 :     forth-wordlist @ (look) ;
82 :    
83 : jwilke 1.9 : look
84 :     dup [ unlock rom-dictionary area lock ]
85 :     literal literal within
86 :     IF
87 : anton 1.13 >head-noprim dup ?? <>
88 : jwilke 1.9 ELSE
89 : anton 1.22 xt>threaded threaded>name
90 : jwilke 1.9 THEN ;
91 :     [ELSE]
92 : jwilke 1.8 : look ( cfa -- lfa flag )
93 : anton 1.13 >head-noprim dup ??? <> ;
94 : jwilke 1.9 [THEN]
95 : jwilke 1.8
96 :     [ELSE]
97 :    
98 : anton 1.13 : PrimStart ['] true >head-noprim ;
99 : jwilke 1.8
100 : anton 1.22 : prim>name ( xt -- lfa flag )
101 :     PrimStart (look) ;
102 :    
103 : anton 1.1 : look ( cfa -- lfa flag )
104 : anton 1.12 dup in-dictionary?
105 : jwilke 1.9 IF
106 : anton 1.13 >head-noprim dup ??? <>
107 : anton 1.12 ELSE
108 : anton 1.22 prim>name
109 : jwilke 1.9 THEN ;
110 : anton 1.1
111 : jwilke 1.8 [THEN]
112 :     [THEN]
113 : anton 1.22
114 :     : threaded>name ( ca -- lfa flag )
115 :     threaded>xt prim>name ;
116 : anton 1.13
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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