Annotation of gforth/look.fs, revision 1.18
1.1 anton 1: \ LOOK.FS xt -> lfa 22may93jaw
2:
1.14 anton 3: \ Copyright (C) 1995,1996,1997,2000 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:
1.1 anton 44: : (look) ( xt startlfa -- lfa flag )
1.17 anton 45: false swap
46: BEGIN
47: @ dup
48: WHILE
1.18 ! anton 49: dup name>int xt>threaded
1.17 anton 50: 3 pick = IF
51: nip dup
52: THEN
53: REPEAT
54: drop nip
55: dup 0<> ;
1.1 anton 56:
1.8 jwilke 57:
58: \ !!! nicht optimal!
59: [IFUNDEF] look
1.9 jwilke 60: has? ec [IF]
61:
1.10 jwilke 62: has? rom
1.8 jwilke 63: [IF]
1.9 jwilke 64: : look
65: dup [ unlock rom-dictionary area lock ]
66: literal literal within
67: IF
1.13 anton 68: >head-noprim dup ?? <>
1.9 jwilke 69: ELSE
70: forth-wordlist @ (look)
71: THEN ;
72: [ELSE]
1.8 jwilke 73: : look ( cfa -- lfa flag )
1.13 anton 74: >head-noprim dup ??? <> ;
1.9 jwilke 75: [THEN]
1.8 jwilke 76:
77: [ELSE]
78:
1.13 anton 79: : PrimStart ['] true >head-noprim ;
1.8 jwilke 80:
1.1 anton 81: : look ( cfa -- lfa flag )
1.12 anton 82: dup in-dictionary?
1.9 jwilke 83: IF
1.13 anton 84: >head-noprim dup ??? <>
1.12 anton 85: ELSE
1.9 jwilke 86: PrimStart (look)
87: THEN ;
1.1 anton 88:
1.8 jwilke 89: [THEN]
90: [THEN]
1.13 anton 91:
92: : >head ( cfa -- nt|0 ) \ gforth to-head
93: \G tries to find the name token nt of the word represented by cfa;
94: \G returns 0 if it fails. This word is not absolutely reliable,
95: \G it may give false positives and produce wrong nts.
96: look and ;
97:
98: ' >head ALIAS >name \ gforth to-name
99: \G old name of @code{>head}
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