ref: 7e8060a09c49aabd3a65154d30639456c7326053
dir: /prefix.c/
/*******************************************************************
** 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 1.0 2001/04/25 18:39:00 jsadler Exp $
*******************************************************************/
/*
** Get the latest Ficl release at http://ficl.sourceforge.net
**
** L I C E N S E and D I S C L A I M E R
**
** Ficl is free software; you can redistribute it and/or
** modify it under the terms of the GNU Lesser General Public
** License as published by the Free Software Foundation; either
** version 2.1 of the License, or (at your option) any later version.
**
** The ficl software code is provided on an "as is" basis without
** warranty of any kind, including, without limitation, the implied
** warranties of merchantability and fitness for a particular purpose
** and their equivalents under the laws of any jurisdiction.
** See the GNU Lesser General Public License for more details.
**
** To view the GNU Lesser General Public License, visit this URL:
** http://www.fsf.org/copyleft/lesser.html
**
** Any third party may reproduce, distribute, or modify the ficl
** software code or any derivative works thereof without any
** compensation or license, provided that the author information
** and this license text are retained in the source code files.
**
** 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 (yay!), please
** send me email at the address above.
*/
#include <string.h>
#include <ctype.h>
#include "ficl.h"
#include "math64.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 corrseponding
** code against the remainder of the word and returns true.
**************************************************************************/
int ficlParsePrefix(FICL_VM *pVM, STRINGINFO si)
{
int i;
FICL_HASH *pHash;
FICL_WORD *pFW = ficlLookup(list_name);
assert(pFW);
pHash = (FICL_HASH *)(pFW->param[0].p);
/*
** Walk the list looking for a match with the beginning of the incoming token
*/
for (i = 0; i < (int)pHash->size; i++)
{
pFW = pHash->table[i];
while (pFW != NULL)
{
int n;
n = pFW->nName;
/*
** If we find a match, adjust the TIB to give back the non-prefix characters
** and execute the prefix word.
*/
if (!strincmp(SI_PTR(si), pFW->name, (FICL_UNS)n))
{
vmSetTibIndex(pVM, vmGetTibIndex(pVM) - 1 - SI_COUNT(si) + n);
vmExecute(pVM, pFW);
return FICL_TRUE;
}
pFW = pFW->link;
}
}
return FICL_FALSE;
}
static void tempBase(FICL_VM *pVM, int base)
{
int oldbase = pVM->base;
STRINGINFO si = vmGetWord0(pVM);
pVM->base = base;
if (!ficlParseNumber(pVM, si))
{
int i = SI_COUNT(si);
vmThrowErr(pVM, "0x%.*s is not a valid hex value", i, SI_PTR(si));
}
pVM->base = oldbase;
return;
}
static void fTempBase(FICL_VM *pVM)
{
int base = stackPopINT(pVM->pStack);
tempBase(pVM, base);
return;
}
static void prefixHex(FICL_VM *pVM)
{
tempBase(pVM, 16);
}
static void prefixTen(FICL_VM *pVM)
{
tempBase(pVM, 10);
}
/**************************************************************************
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 ficlCompilePrefix(FICL_SYSTEM *pSys)
{
FICL_DICT *dp = pSys->dp;
FICL_HASH *pHash;
FICL_HASH *pPrevCompile = dp->pCompile;
#if (FICL_EXTENDED_PREFIX)
FICL_WORD *pFW;
#endif
/*
** 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.
*/
pHash = dictCreateWordlist(dp, 1);
pHash->name = list_name;
dictAppendWord(dp, list_name, constantParen, FW_DEFAULT);
dictAppendCell(dp, LVALUEtoCELL(pHash));
dictAppendWord(dp, "__tempbase", fTempBase, FW_DEFAULT);
/*
** Temporarily make the prefix list the compile wordlist so that
** we can create some precompiled prefixes.
*/
dp->pCompile = pHash;
dictAppendWord(dp, "0x", prefixHex, FW_DEFAULT);
dictAppendWord(dp, "0d", prefixTen, FW_DEFAULT);
#if (FICL_EXTENDED_PREFIX)
pFW = ficlLookup("\\");
if (pFW)
{
dictAppendWord(dp, "//", pFW->code, FW_DEFAULT);
}
#endif
dp->pCompile = pPrevCompile;
ficlAddPrecompiledParseStep(pSys, "prefix?", ficlParsePrefix);
return;
}