lua.lua/lex.c

char *rcs_lex = "$Id: lex.c,v 2.7 1994/10/17 19:01:53 celes Exp celes $";
/*$Log: lex.c,v $
 * Revision 2.7  1994/10/17  19:01:53  celes
 * new algorithm for reading floats.
 * files end with EOF, instead of 0.
 *
 * Revision 2.6  1994/09/26  16:21:52  celes
 * Mudancas para tornar lex.c um modulo independente dos outros
 * modulos de Lua
 *
 * Revision 2.5  1994/09/22  12:44:00  lhf
 * added support for ugly tokens
 *
 * Revision 2.4  1994/09/05  19:14:40  celes
 * escapes \' e \" em strings; correcao do escape \\
 *
 * Revision 2.3  1994/08/17  17:41:50  celes
 * Implementacao da macro 'lua_strcmp'
 *
 * Revision 2.2  1994/08/05  19:27:41  celes
 * implementacao de dois buffer de 'yytext' para evitar bug
 * no look ahead do yacc
 *
 * Revision 2.1  1994/04/15  19:00:28  celes
 * Retirar chamada da funcao lua_findsymbol associada a cada
 * token NAME. A decisao de chamar lua_findsymbol ou lua_findconstant
 * fica a cargo do modulo "lua.stx".
 *
 * Revision 1.3  1993/12/28  16:42:29  roberto
 * "include"s de string.h e stdlib.h para evitar warnings
 *
 * Revision 1.2  1993/12/22  21:39:15  celes
 * Tratamento do token $debug e $nodebug
 *
 * Revision 1.1  1993/12/22  21:15:16  roberto
 * Initial revision
 **/

#include <ctype.h>
#include <math.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "opcode.h"
#include "inout.h"
#include "y.tab.h"
#include "ugly.h"

#define lua_strcmp(a,b)	(a[0]<b[0]?(-1):(a[0]>b[0]?(1):strcmp(a,b)))

#define next() { current = input(); }
#define save(x) { *yytextLast++ = (x); }
#define save_and_next()  { save(current); next(); }

static int current;
static char yytext[2][256];
static char *yytextLast;
static int currentText = 0;

static Input input;

void lua_setinput (Input fn)
{
  current = ' ';
  input = fn;
}

char *lua_lasttext (void)
{
  *yytextLast = 0;
  return yytext[currentText];
}


/* The reserved words must be listed in lexicographic order */
static struct
  {
    char *name;
    int token;
  } reserved [] = {
      {"and", AND},
      {"do", DO},
      {"else", ELSE},
      {"elseif", ELSEIF},
      {"end", END},
      {"function", FUNCTION},
      {"if", IF},
      {"local", LOCAL},
      {"nil", NIL},
      {"not", NOT},
      {"or", OR},
      {"repeat", REPEAT},
      {"return", RETURN},
      {"then", THEN},
      {"until", UNTIL},
      {"while", WHILE} };


#define RESERVEDSIZE (sizeof(reserved)/sizeof(reserved[0]))


static int findReserved (char *name)
{
  int l = 0;
  int h = RESERVEDSIZE - 1;
  while (l <= h)
  {
    int m = (l+h)/2;
    int comp = lua_strcmp(name, reserved[m].name);
    if (comp < 0)
      h = m-1;
    else if (comp == 0)
      return reserved[m].token;
    else
      l = m+1;
  }
  return 0;
}


int yylex ()
{
  float a;
  currentText = !currentText;
  while (1)
  {
    yytextLast = yytext[currentText];
#if 0
    fprintf(stderr,"'%c' %d\n",current,current);
#endif
    switch (current)
    {
      case EOF:
      case 0:
       return 0;
      case '\n': lua_linenumber++;
      case ' ':
      case '\t':
        next();
        continue;

      case '$':
	next();
	while (isalnum(current) || current == '_')
          save_and_next();
        *yytextLast = 0;
	if (lua_strcmp(yytext[currentText], "debug") == 0)
	{
	  yylval.vInt = 1;
	  return DEBUG;
        }
	else if (lua_strcmp(yytext[currentText], "nodebug") == 0)
	{
	  yylval.vInt = 0;
	  return DEBUG;
        }
	return WRONGTOKEN;

      case '-':
        save_and_next();
        if (current != '-') return '-';
        do { next(); } while (current != '\n' && current != 0);
        continue;

      case '=':
        save_and_next();
        if (current != '=') return '=';
        else { save_and_next(); return EQ; }

      case '<':
        save_and_next();
        if (current != '=') return '<';
        else { save_and_next(); return LE; }

      case '>':
        save_and_next();
        if (current != '=') return '>';
        else { save_and_next(); return GE; }

      case '~':
        save_and_next();
        if (current != '=') return '~';
        else { save_and_next(); return NE; }

      case '"':
      case '\'':
      {
        int del = current;
        next();  /* skip the delimiter */
        while (current != del)
        {
          switch (current)
          {
            case EOF:
            case 0:
            case '\n':
              return WRONGTOKEN;
            case '\\':
              next();  /* do not save the '\' */
              switch (current)
              {
                case 'n': save('\n'); next(); break;
                case 't': save('\t'); next(); break;
                case 'r': save('\r'); next(); break;
                case '\'': save('\''); next(); break;
                case '"': save('"'); next(); break;
                default : save(current); next(); break;
              }
              break;
            default:
              save_and_next();
          }
        }
        next();  /* skip the delimiter */
        *yytextLast = 0;
        yylval.pChar = yytext[currentText];
        return STRING;
      }

      case 'a': case 'b': case 'c': case 'd': case 'e':
      case 'f': case 'g': case 'h': case 'i': case 'j':
      case 'k': case 'l': case 'm': case 'n': case 'o':
      case 'p': case 'q': case 'r': case 's': case 't':
      case 'u': case 'v': case 'w': case 'x': case 'y':
      case 'z':
      case 'A': case 'B': case 'C': case 'D': case 'E':
      case 'F': case 'G': case 'H': case 'I': case 'J':
      case 'K': case 'L': case 'M': case 'N': case 'O':
      case 'P': case 'Q': case 'R': case 'S': case 'T':
      case 'U': case 'V': case 'W': case 'X': case 'Y':
      case 'Z':
      case '_':
      {
        int res;
        do { save_and_next(); } while (isalnum(current) || current == '_');
        *yytextLast = 0;
        res = findReserved(yytext[currentText]);
        if (res) return res;
        yylval.pChar = yytext[currentText];
        return NAME;
      }

      case '.':
        save_and_next();
        if (current == '.')
        {
          save_and_next();
          return CONC;
        }
        else if (!isdigit(current)) return '.';
        /* current is a digit: goes through to number */
	a=0.0;
        goto fraction;

      case '0': case '1': case '2': case '3': case '4':
      case '5': case '6': case '7': case '8': case '9':
	a=0.0;
        do { a=10*a+current-'0'; save_and_next(); } while (isdigit(current));
        if (current == '.') save_and_next();
fraction:
	{ float da=0.1;
	  while (isdigit(current))
	  {a+=(current-'0')*da; da/=10.0; save_and_next()};
          if (current == 'e' || current == 'E')
          {
	    int e=0;
	    int neg;
	    float ea;
            save_and_next();
	    neg=(current=='-');
            if (current == '+' || current == '-') save_and_next();
            if (!isdigit(current)) return WRONGTOKEN;
            do { e=10*e+current-'0'; save_and_next(); } while (isdigit(current));
	    for (ea=neg?0.1:10.0; e>0; e>>=1) 
	    {
	      if (e & 1) a*=ea;
	      ea*=ea;
	    }
          }
          yylval.vFloat = a;
          return NUMBER;
        }
      case U_and:	next(); return AND;
      case U_do:	next(); return DO;
      case U_else:	next(); return ELSE;
      case U_elseif:	next(); return ELSEIF;
      case U_end:	next(); return END;
      case U_function:	next(); return FUNCTION;
      case U_if:	next(); return IF;
      case U_local:	next(); return LOCAL;
      case U_nil:	next(); return NIL;
      case U_not:	next(); return NOT;
      case U_or:	next(); return OR;
      case U_repeat:	next(); return REPEAT;
      case U_return:	next(); return RETURN;
      case U_then:	next(); return THEN;
      case U_until:	next(); return UNTIL;
      case U_while:	next(); return WHILE;
      case U_eq:	next(); return EQ;
      case U_le:	next(); return LE;
      case U_ge:	next(); return GE;
      case U_ne:	next(); return NE;
      case U_sc:	next(); return CONC;

      default: 		/* also end of file */
      {
        save_and_next();
        return yytext[currentText][0];
      }
    }
  }
}