1 /*
2 * p r e f i x . c
3 * Forth Inspired Command Language
4 * Parser extensions for Ficl
5 * Authors: Larry Hastings & John Sadler (john_sadler@alum.mit.edu)
6 * Created: April 2001
7 * $Id: prefix.c,v 1.8 2010/09/13 18:43:04 asau Exp $
8 */
9 /*
10 * Copyright (c) 1997-2001 John Sadler (john_sadler@alum.mit.edu)
11 * All rights reserved.
12 *
13 * Get the latest Ficl release at http://ficl.sourceforge.net
14 *
15 * I am interested in hearing from anyone who uses Ficl. If you have
16 * a problem, a success story, a defect, an enhancement request, or
17 * if you would like to contribute to the Ficl release, please
18 * contact me by email at the address above.
19 *
20 * L I C E N S E and D I S C L A I M E R
21 *
22 * Redistribution and use in source and binary forms, with or without
23 * modification, are permitted provided that the following conditions
24 * are met:
25 * 1. Redistributions of source code must retain the above copyright
26 * notice, this list of conditions and the following disclaimer.
27 * 2. Redistributions in binary form must reproduce the above copyright
28 * notice, this list of conditions and the following disclaimer in the
29 * documentation and/or other materials provided with the distribution.
30 *
31 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
32 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
33 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
34 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
35 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
36 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
37 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
38 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
39 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
40 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
41 * SUCH DAMAGE.
42 */
43
44 #include "ficl.h"
45
46 /*
47 * (jws) revisions:
48 * A prefix is a word in a dedicated wordlist (name stored in list_name below)
49 * that is searched in a special way by the prefix parse step. When a prefix
50 * matches the beginning of an incoming token, push the non-prefix part of the
51 * token back onto the input stream and execute the prefix code.
52 *
53 * The parse step is called ficlParsePrefix.
54 * Storing prefix entries in the dictionary greatly simplifies
55 * the process of matching and dispatching prefixes, avoids the
56 * need to clean up a dynamically allocated prefix list when the system
57 * goes away, but still allows prefixes to be allocated at runtime.
58 */
59
60 static char list_name[] = "<prefixes>";
61
62 /*
63 * f i c l P a r s e P r e f i x
64 * This is the parse step for prefixes - it checks an incoming word
65 * to see if it starts with a prefix, and if so runs the corresponding
66 * code against the remainder of the word and returns true.
67 */
68 int
ficlVmParsePrefix(ficlVm * vm,ficlString s)69 ficlVmParsePrefix(ficlVm *vm, ficlString s)
70 {
71 int i;
72 ficlHash *hash;
73 ficlWord *word = ficlSystemLookup(vm->callback.system, list_name);
74
75 /*
76 * Make sure we found the prefix dictionary - otherwise silently fail
77 * If forth-wordlist is not in the search order, we won't find the
78 * prefixes.
79 */
80 if (!word)
81 return (0); /* false */
82
83 hash = (ficlHash *)(word->param[0].p);
84 /*
85 * Walk the list looking for a match with the beginning of the
86 * incoming token
87 */
88 for (i = 0; i < (int)hash->size; i++) {
89 word = hash->table[i];
90 while (word != NULL) {
91 int n;
92 n = word->length;
93 /*
94 * If we find a match, adjust the TIB to give back
95 * the non-prefix characters and execute the prefix
96 * word.
97 */
98 if (!ficlStrincmp(FICL_STRING_GET_POINTER(s),
99 word->name, (ficlUnsigned)n)) {
100 /*
101 * (sadler) fixed off-by-one error when the
102 * token has no trailing space in the TIB
103 */
104 ficlVmSetTibIndex(vm,
105 s.text + n - vm->tib.text);
106 ficlVmExecuteWord(vm, word);
107
108 return (1); /* true */
109 }
110 word = word->link;
111 }
112 }
113
114 return (0); /* false */
115 }
116
117 static void
ficlPrimitiveTempBase(ficlVm * vm)118 ficlPrimitiveTempBase(ficlVm *vm)
119 {
120 int oldbase = vm->base;
121 ficlString number = ficlVmGetWord0(vm);
122 int base = ficlStackPopInteger(vm->dataStack);
123
124 vm->base = base;
125 if (!ficlVmParseNumber(vm, number))
126 ficlVmThrowError(vm, "%.*s not recognized",
127 FICL_STRING_GET_LENGTH(number),
128 FICL_STRING_GET_POINTER(number));
129
130 vm->base = oldbase;
131 }
132
133 /*
134 * f i c l C o m p i l e P r e f i x
135 * Build prefix support into the dictionary and the parser
136 * Note: since prefixes always execute, they are effectively IMMEDIATE.
137 * If they need to generate code in compile state you must add
138 * this code explicitly.
139 */
140 void
ficlSystemCompilePrefix(ficlSystem * system)141 ficlSystemCompilePrefix(ficlSystem *system)
142 {
143 ficlDictionary *dictionary = system->dictionary;
144 ficlHash *hash;
145
146 /*
147 * Create a named wordlist for prefixes to reside in...
148 * Since we're doing a special kind of search, make it
149 * a single bucket hashtable - hashing does not help here.
150 */
151 hash = ficlDictionaryCreateWordlist(dictionary, 1);
152 hash->name = list_name;
153 ficlDictionaryAppendConstantPointer(dictionary, list_name, hash);
154
155 /*
156 * Put __tempbase in the forth-wordlist
157 */
158 (void) ficlDictionarySetPrimitive(dictionary, "__tempbase",
159 ficlPrimitiveTempBase, FICL_WORD_DEFAULT);
160
161 /*
162 * If you want to add some prefixes at compilation-time, copy this
163 * line to the top of this function:
164 *
165 * ficlHash *oldCompilationWordlist;
166 *
167 * then copy this code to the bottom, just above the return:
168 *
169 *
170 * oldCompilationWordlist = dictionary->compilationWordlist;
171 * dictionary->compilationWordlist = hash;
172 * ficlDictionarySetPrimitive(dictionary, YOUR WORD HERE,
173 * FICL_WORD_DEFAULT);
174 * dictionary->compilationWordlist = oldCompilationWordlist;
175 *
176 * and substitute in your own actual calls to
177 * ficlDictionarySetPrimitive() as needed.
178 *
179 * Or--better yet--do it in your own code, so you don't have
180 * to re-modify the Ficl source code every time we cut a new release!
181 */
182 }
183