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    1: /* Lexer for formula answers
    2:    Copyright (C) 1992-2000 Michigan State University
    3: 
    4:    The CAPA system is free software; you can redistribute it and/or
    5:    modify it under the terms of the GNU Library General Public License as
    6:    published by the Free Software Foundation; either version 2 of the
    7:    License, or (at your option) any later version.
    8: 
    9:    The CAPA system is distributed in the hope that it will be useful,
   10:    but WITHOUT ANY WARRANTY; without even the implied warranty of
   11:    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   12:    Library General Public License for more details.
   13: 
   14:    You should have received a copy of the GNU Library General Public
   15:    License along with the CAPA system; see the file COPYING.  If not,
   16:    write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
   17:    Boston, MA 02111-1307, USA.
   18: 
   19:    As a special exception, you have permission to link this program
   20:    with the TtH/TtM library and distribute executables, as long as you
   21:    follow the requirements of the GNU GPL in regard to all of the
   22:    software in the executable aside from TtH/TtM.
   23: */
   24: 
   25: /* =========================================================== */
   26: /*      capaFormulaLexer.c  created by Isaac Tsai @ Feb 1999   */
   27: /* =========================================================== */
   28: 
   29: #include <ctype.h>    /* isspace() */
   30: #include <stdio.h>    /* sscanf()  */
   31: #include "capaParser.h"
   32: #define YYSTYPE  Symbol_p
   33: #include "capaFormula.h"
   34: #include "capaToken.h"
   35: 
   36: /* ---------------  Global variables ------------------------- */
   37: extern      int         Func_idx;
   38: extern      Symbol      FuncStack[MAX_FUNC_NEST];
   39: 
   40: 
   41: extern      char        Fbuf[ONE_K];          /* lexer input buffer */
   42: extern      int         Fidx;                 /* lexer input char index */
   43: 
   44: extern      Symbol_p    fml_lval;  /* lexical variable used in parser */
   45: 
   46: /* ---- Token value returned from this lexer ---------------- */
   47: 
   48: /* ---------------  Global variables ------------------------ */
   49: 
   50: 
   51: /* scan a F_NUMBER token */
   52: double
   53: f_get_float()
   54: {
   55:   double   num; 
   56:   int      ii=0, len;
   57:   char     num_str[QUARTER_K];
   58:   
   59:   num_str[ii]=0;
   60:   while( isspace(Fbuf[Fidx]) ) { Fidx++; }
   61:   if( Fbuf[Fidx] == '+' || Fbuf[Fidx] == '-' ) {
   62:     num_str[ii++] = Fbuf[Fidx++];
   63:   }
   64:   while( isdigit(Fbuf[Fidx]) || Fbuf[Fidx] == '.' ) {
   65:       num_str[ii++] = Fbuf[Fidx++];
   66:   }
   67:   if( Fbuf[Fidx] == 'E' || Fbuf[Fidx] == 'e' ) {  /* a number followed immediately by e or E */
   68:     if( Fbuf[Fidx+1] == '+' || Fbuf[Fidx+1] == '-' || isdigit(Fbuf[Fidx+1]) ) {  
   69:     /* e or E followed immediately by a digit */
   70:       num_str[ii++] = Fbuf[Fidx++];
   71:       num_str[ii++] = Fbuf[Fidx++];
   72:       while( isdigit(Fbuf[Fidx]) ) {
   73:         num_str[ii++] = Fbuf[Fidx++];
   74:       }
   75:     }
   76:   }
   77:   num_str[ii] = 0; /* terminate the str */
   78:   len = strlen(num_str);
   79:   if(len > 0 ) {
   80:     sscanf(num_str,"%lg", &num);
   81:   } else {
   82:     num = 1.0;
   83:   }
   84:   return (num);
   85: }
   86: 
   87: char *
   88: f_get_id()
   89: {
   90:   char    *var_p; 
   91:   int      ii=0, len;
   92:   char     id_str[QUARTER_K];
   93:   
   94:   id_str[ii]=0;
   95:   while( isspace(Fbuf[Fidx]) ) { Fidx++; }
   96:   if( isalpha( Fbuf[Fidx] ) ) {
   97:     id_str[ii++] = Fbuf[Fidx++];
   98:   }
   99:   while( isalnum(Fbuf[Fidx]) || Fbuf[Fidx] == '_' ) {
  100:       id_str[ii++] = Fbuf[Fidx++];
  101:   }
  102:   id_str[ii] = 0; /* terminate the str */
  103:   len = strlen(id_str);
  104:   var_p = (char *)capa_malloc( (len+1), sizeof(char));
  105:   strcpy(var_p,id_str);
  106:   return (var_p);
  107: }
  108: 
  109: int
  110: f_peek_next_token()
  111: {
  112:   int   idx;
  113:   
  114:   idx = Fidx;
  115:   while( isspace(Fbuf[idx]) ) { idx++; }
  116:   return (Fbuf[idx]); 
  117: }
  118: 
  119: 
  120: /* ======================================================= */
  121: 
  122: int
  123: fml_lex()
  124: {
  125:   char    *id_p;
  126:   int      c;
  127:   
  128:   if( Fbuf[Fidx] == 0 )  { /* printf("EoI\n"); */ return (EOF); }
  129:   while( isspace(Fbuf[Fidx]) ) { Fidx++; }
  130:   if( isalpha(Fbuf[Fidx]) ) {
  131:     id_p = f_get_id();
  132:     c = f_peek_next_token();
  133:     if( c == '(' ) {
  134:       (FuncStack[Func_idx]).s_type = FUNCTION_ID;
  135:       (FuncStack[Func_idx]).s_name = id_p;
  136:        Func_idx++;
  137:        
  138:        return (F_ID);
  139:     } else {
  140:       fml_lval = find_formula_id(id_p); capa_mfree((char *)id_p);
  141:       if( fml_lval == NULL) {
  142:         return (F_ERROR);
  143:       } else {
  144:         return (V_ID);
  145:       }
  146:     } 
  147:   }
  148:   if( isdigit(Fbuf[Fidx]) || Fbuf[Fidx] == '.' ) {
  149:     
  150:     fml_lval = (Symbol *) capa_malloc(1, sizeof(Symbol)); /* *** */
  151:     fml_lval->s_real = f_get_float();
  152:     fml_lval->s_type = R_CONSTANT;
  153:     
  154:     return (F_NUMBER);
  155:   }
  156:   if( Fbuf[Fidx] == '(' ) {
  157:     Fidx++;
  158:     return (F_LPAR);
  159:   }
  160:   if( Fbuf[Fidx] == ')' ) {
  161:     Fidx++;
  162:     return (F_RPAR);
  163:   }
  164:   if( Fbuf[Fidx] == '+' ) {
  165:     Fidx++;
  166:     return (F_PLUS);
  167:   }
  168:   if( Fbuf[Fidx] == '-' ) {
  169:     Fidx++;
  170:     return (F_MINUS);
  171:   }
  172:   if( Fbuf[Fidx] == '*' ) {
  173:     Fidx++;
  174:     return (F_MULT);
  175:   }
  176:   if( Fbuf[Fidx] == '/' ) {
  177:     Fidx++;
  178:     return (F_DIV);
  179:   }
  180:   if( Fbuf[Fidx] == '%' ) {
  181:     Fidx++;
  182:     return (F_MOD);
  183:   }
  184:   if( Fbuf[Fidx] == '^' ) {
  185:     Fidx++;
  186:     return (F_POW);
  187:   }
  188:   if( Fbuf[Fidx] == ',' ) {
  189:     Fidx++;
  190:     return (F_COMMA);
  191:   }
  192:   return (F_ERROR);
  193:   
  194: }