mirror of https://github.com/lua/lua
314 lines
7.9 KiB
C
314 lines
7.9 KiB
C
char *rcs_lex = "$Id: lex.c,v 2.7 1994/10/17 19:01:53 celes Exp celes $";
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/*$Log: lex.c,v $
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* Revision 2.7 1994/10/17 19:01:53 celes
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* new algorithm for reading floats.
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* files end with EOF, instead of 0.
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*
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* Revision 2.6 1994/09/26 16:21:52 celes
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* Mudancas para tornar lex.c um modulo independente dos outros
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* modulos de Lua
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*
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* Revision 2.5 1994/09/22 12:44:00 lhf
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* added support for ugly tokens
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*
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* Revision 2.4 1994/09/05 19:14:40 celes
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* escapes \' e \" em strings; correcao do escape \\
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*
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* Revision 2.3 1994/08/17 17:41:50 celes
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* Implementacao da macro 'lua_strcmp'
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*
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* Revision 2.2 1994/08/05 19:27:41 celes
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* implementacao de dois buffer de 'yytext' para evitar bug
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* no look ahead do yacc
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*
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* Revision 2.1 1994/04/15 19:00:28 celes
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* Retirar chamada da funcao lua_findsymbol associada a cada
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* token NAME. A decisao de chamar lua_findsymbol ou lua_findconstant
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* fica a cargo do modulo "lua.stx".
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*
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* Revision 1.3 1993/12/28 16:42:29 roberto
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* "include"s de string.h e stdlib.h para evitar warnings
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*
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* Revision 1.2 1993/12/22 21:39:15 celes
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* Tratamento do token $debug e $nodebug
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*
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* Revision 1.1 1993/12/22 21:15:16 roberto
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* Initial revision
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**/
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#include <ctype.h>
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#include <math.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include "opcode.h"
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#include "inout.h"
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#include "y.tab.h"
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#include "ugly.h"
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#define lua_strcmp(a,b) (a[0]<b[0]?(-1):(a[0]>b[0]?(1):strcmp(a,b)))
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#define next() { current = input(); }
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#define save(x) { *yytextLast++ = (x); }
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#define save_and_next() { save(current); next(); }
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static int current;
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static char yytext[2][256];
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static char *yytextLast;
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static int currentText = 0;
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static Input input;
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void lua_setinput (Input fn)
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{
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current = ' ';
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input = fn;
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}
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char *lua_lasttext (void)
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{
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*yytextLast = 0;
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return yytext[currentText];
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}
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/* The reserved words must be listed in lexicographic order */
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static struct
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{
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char *name;
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int token;
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} reserved [] = {
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{"and", AND},
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{"do", DO},
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{"else", ELSE},
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{"elseif", ELSEIF},
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{"end", END},
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{"function", FUNCTION},
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{"if", IF},
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{"local", LOCAL},
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{"nil", NIL},
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{"not", NOT},
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{"or", OR},
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{"repeat", REPEAT},
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{"return", RETURN},
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{"then", THEN},
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{"until", UNTIL},
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{"while", WHILE} };
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#define RESERVEDSIZE (sizeof(reserved)/sizeof(reserved[0]))
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static int findReserved (char *name)
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{
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int l = 0;
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int h = RESERVEDSIZE - 1;
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while (l <= h)
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{
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int m = (l+h)/2;
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int comp = lua_strcmp(name, reserved[m].name);
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if (comp < 0)
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h = m-1;
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else if (comp == 0)
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return reserved[m].token;
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else
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l = m+1;
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}
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return 0;
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}
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int yylex ()
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{
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float a;
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currentText = !currentText;
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while (1)
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{
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yytextLast = yytext[currentText];
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#if 0
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fprintf(stderr,"'%c' %d\n",current,current);
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#endif
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switch (current)
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{
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case EOF:
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case 0:
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return 0;
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case '\n': lua_linenumber++;
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case ' ':
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case '\t':
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next();
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continue;
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case '$':
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next();
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while (isalnum(current) || current == '_')
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save_and_next();
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*yytextLast = 0;
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if (lua_strcmp(yytext[currentText], "debug") == 0)
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{
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yylval.vInt = 1;
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return DEBUG;
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}
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else if (lua_strcmp(yytext[currentText], "nodebug") == 0)
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{
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yylval.vInt = 0;
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return DEBUG;
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}
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return WRONGTOKEN;
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case '-':
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save_and_next();
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if (current != '-') return '-';
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do { next(); } while (current != '\n' && current != 0);
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continue;
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case '=':
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save_and_next();
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if (current != '=') return '=';
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else { save_and_next(); return EQ; }
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case '<':
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save_and_next();
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if (current != '=') return '<';
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else { save_and_next(); return LE; }
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case '>':
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save_and_next();
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if (current != '=') return '>';
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else { save_and_next(); return GE; }
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case '~':
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save_and_next();
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if (current != '=') return '~';
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else { save_and_next(); return NE; }
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case '"':
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case '\'':
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{
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int del = current;
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next(); /* skip the delimiter */
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while (current != del)
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{
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switch (current)
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{
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case EOF:
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case 0:
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case '\n':
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return WRONGTOKEN;
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case '\\':
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next(); /* do not save the '\' */
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switch (current)
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{
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case 'n': save('\n'); next(); break;
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case 't': save('\t'); next(); break;
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case 'r': save('\r'); next(); break;
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case '\'': save('\''); next(); break;
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case '"': save('"'); next(); break;
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default : save(current); next(); break;
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}
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break;
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default:
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save_and_next();
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}
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}
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next(); /* skip the delimiter */
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*yytextLast = 0;
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yylval.pChar = yytext[currentText];
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return STRING;
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}
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case 'a': case 'b': case 'c': case 'd': case 'e':
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case 'f': case 'g': case 'h': case 'i': case 'j':
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case 'k': case 'l': case 'm': case 'n': case 'o':
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case 'p': case 'q': case 'r': case 's': case 't':
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case 'u': case 'v': case 'w': case 'x': case 'y':
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case 'z':
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case 'A': case 'B': case 'C': case 'D': case 'E':
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case 'F': case 'G': case 'H': case 'I': case 'J':
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case 'K': case 'L': case 'M': case 'N': case 'O':
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case 'P': case 'Q': case 'R': case 'S': case 'T':
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case 'U': case 'V': case 'W': case 'X': case 'Y':
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case 'Z':
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case '_':
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{
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int res;
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do { save_and_next(); } while (isalnum(current) || current == '_');
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*yytextLast = 0;
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res = findReserved(yytext[currentText]);
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if (res) return res;
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yylval.pChar = yytext[currentText];
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return NAME;
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}
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case '.':
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save_and_next();
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if (current == '.')
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{
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save_and_next();
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return CONC;
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}
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else if (!isdigit(current)) return '.';
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/* current is a digit: goes through to number */
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a=0.0;
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goto fraction;
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case '0': case '1': case '2': case '3': case '4':
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case '5': case '6': case '7': case '8': case '9':
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a=0.0;
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do { a=10*a+current-'0'; save_and_next(); } while (isdigit(current));
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if (current == '.') save_and_next();
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fraction:
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{ float da=0.1;
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while (isdigit(current))
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{a+=(current-'0')*da; da/=10.0; save_and_next()};
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if (current == 'e' || current == 'E')
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{
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int e=0;
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int neg;
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float ea;
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save_and_next();
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neg=(current=='-');
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if (current == '+' || current == '-') save_and_next();
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if (!isdigit(current)) return WRONGTOKEN;
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do { e=10*e+current-'0'; save_and_next(); } while (isdigit(current));
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for (ea=neg?0.1:10.0; e>0; e>>=1)
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{
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if (e & 1) a*=ea;
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ea*=ea;
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}
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}
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yylval.vFloat = a;
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return NUMBER;
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}
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case U_and: next(); return AND;
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case U_do: next(); return DO;
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case U_else: next(); return ELSE;
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case U_elseif: next(); return ELSEIF;
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case U_end: next(); return END;
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case U_function: next(); return FUNCTION;
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case U_if: next(); return IF;
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case U_local: next(); return LOCAL;
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case U_nil: next(); return NIL;
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case U_not: next(); return NOT;
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case U_or: next(); return OR;
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case U_repeat: next(); return REPEAT;
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case U_return: next(); return RETURN;
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case U_then: next(); return THEN;
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case U_until: next(); return UNTIL;
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case U_while: next(); return WHILE;
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case U_eq: next(); return EQ;
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case U_le: next(); return LE;
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case U_ge: next(); return GE;
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case U_ne: next(); return NE;
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case U_sc: next(); return CONC;
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default: /* also end of file */
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{
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save_and_next();
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return yytext[currentText][0];
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}
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}
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}
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}
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