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Diffstat (limited to 'usr/src/common/ficl/prefix.c')
| -rw-r--r-- | usr/src/common/ficl/prefix.c | 182 |
1 files changed, 182 insertions, 0 deletions
diff --git a/usr/src/common/ficl/prefix.c b/usr/src/common/ficl/prefix.c new file mode 100644 index 0000000000..8e396d92cb --- /dev/null +++ b/usr/src/common/ficl/prefix.c @@ -0,0 +1,182 @@ +/* + * p r e f i x . c + * Forth Inspired Command Language + * Parser extensions for Ficl + * Authors: Larry Hastings & John Sadler (john_sadler@alum.mit.edu) + * Created: April 2001 + * $Id: prefix.c,v 1.8 2010/09/13 18:43:04 asau Exp $ + */ +/* + * Copyright (c) 1997-2001 John Sadler (john_sadler@alum.mit.edu) + * All rights reserved. + * + * Get the latest Ficl release at http://ficl.sourceforge.net + * + * I am interested in hearing from anyone who uses Ficl. If you have + * a problem, a success story, a defect, an enhancement request, or + * if you would like to contribute to the Ficl release, please + * contact me by email at the address above. + * + * L I C E N S E and D I S C L A I M E R + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * + * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF + * SUCH DAMAGE. + */ + +#include "ficl.h" + +/* + * (jws) revisions: + * A prefix is a word in a dedicated wordlist (name stored in list_name below) + * that is searched in a special way by the prefix parse step. When a prefix + * matches the beginning of an incoming token, push the non-prefix part of the + * token back onto the input stream and execute the prefix code. + * + * The parse step is called ficlParsePrefix. + * Storing prefix entries in the dictionary greatly simplifies + * the process of matching and dispatching prefixes, avoids the + * need to clean up a dynamically allocated prefix list when the system + * goes away, but still allows prefixes to be allocated at runtime. + */ + +static char list_name[] = "<prefixes>"; + +/* + * f i c l P a r s e P r e f i x + * This is the parse step for prefixes - it checks an incoming word + * to see if it starts with a prefix, and if so runs the corresponding + * code against the remainder of the word and returns true. + */ +int +ficlVmParsePrefix(ficlVm *vm, ficlString s) +{ + int i; + ficlHash *hash; + ficlWord *word = ficlSystemLookup(vm->callback.system, list_name); + + /* + * Make sure we found the prefix dictionary - otherwise silently fail + * If forth-wordlist is not in the search order, we won't find the + * prefixes. + */ + if (!word) + return (0); /* false */ + + hash = (ficlHash *)(word->param[0].p); + /* + * Walk the list looking for a match with the beginning of the + * incoming token + */ + for (i = 0; i < (int)hash->size; i++) { + word = hash->table[i]; + while (word != NULL) { + int n; + n = word->length; + /* + * If we find a match, adjust the TIB to give back + * the non-prefix characters and execute the prefix + * word. + */ + if (!ficlStrincmp(FICL_STRING_GET_POINTER(s), + word->name, (ficlUnsigned)n)) { + /* + * (sadler) fixed off-by-one error when the + * token has no trailing space in the TIB + */ + ficlVmSetTibIndex(vm, + s.text + n - vm->tib.text); + ficlVmExecuteWord(vm, word); + + return (1); /* true */ + } + word = word->link; + } + } + + return (0); /* false */ +} + +static void +ficlPrimitiveTempBase(ficlVm *vm) +{ + int oldbase = vm->base; + ficlString number = ficlVmGetWord0(vm); + int base = ficlStackPopInteger(vm->dataStack); + + vm->base = base; + if (!ficlVmParseNumber(vm, number)) + ficlVmThrowError(vm, "%.*s not recognized", + FICL_STRING_GET_LENGTH(number), + FICL_STRING_GET_POINTER(number)); + + vm->base = oldbase; +} + +/* + * f i c l C o m p i l e P r e f i x + * Build prefix support into the dictionary and the parser + * Note: since prefixes always execute, they are effectively IMMEDIATE. + * If they need to generate code in compile state you must add + * this code explicitly. + */ +void +ficlSystemCompilePrefix(ficlSystem *system) +{ + ficlDictionary *dictionary = system->dictionary; + ficlHash *hash; + + /* + * Create a named wordlist for prefixes to reside in... + * Since we're doing a special kind of search, make it + * a single bucket hashtable - hashing does not help here. + */ + hash = ficlDictionaryCreateWordlist(dictionary, 1); + hash->name = list_name; + ficlDictionaryAppendConstantPointer(dictionary, list_name, hash); + + /* + * Put __tempbase in the forth-wordlist + */ + ficlDictionarySetPrimitive(dictionary, "__tempbase", + ficlPrimitiveTempBase, FICL_WORD_DEFAULT); + + /* + * If you want to add some prefixes at compilation-time, copy this + * line to the top of this function: + * + * ficlHash *oldCompilationWordlist; + * + * then copy this code to the bottom, just above the return: + * + * + * oldCompilationWordlist = dictionary->compilationWordlist; + * dictionary->compilationWordlist = hash; + * ficlDictionarySetPrimitive(dictionary, YOUR WORD HERE, + * FICL_WORD_DEFAULT); + * dictionary->compilationWordlist = oldCompilationWordlist; + * + * and substitute in your own actual calls to + * ficlDictionarySetPrimitive() as needed. + * + * Or--better yet--do it in your own code, so you don't have + * to re-modify the Ficl source code every time we cut a new release! + */ +} |