mirror of
https://github.com/lua/lua
synced 2024-12-29 05:39:52 +03:00
357 lines
8.4 KiB
C
357 lines
8.4 KiB
C
char *rcs_lex = "$Id: lex.c,v 2.21 1995/11/16 20:46:24 roberto Exp roberto $";
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#include <ctype.h>
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#include <string.h>
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#include <stdio.h>
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#include "mem.h"
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#include "tree.h"
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#include "table.h"
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#include "opcode.h"
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#include "inout.h"
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#include "parser.h"
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#include "ugly.h"
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#define MINBUFF 260
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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 = NULL;
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static int textsize = 0;
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static char *yytextLast;
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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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if (yytext == NULL)
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{
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textsize = MINBUFF;
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yytext = newvector(textsize, char);
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}
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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;
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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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static void growtext (void)
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{
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int size = yytextLast - yytext;
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textsize *= 2;
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yytext = growvector(yytext, textsize, char);
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yytextLast = yytext + size;
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}
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static int read_long_string (void)
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{
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int cont = 0;
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int spaceleft = textsize - (yytextLast - yytext);
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while (1)
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{
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if (spaceleft <= 2) /* may read more than 1 char in one cicle */
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{
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growtext();
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spaceleft = textsize - (yytextLast - yytext);
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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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return WRONGTOKEN;
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case '[':
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save_and_next(); spaceleft--;
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if (current == '[')
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{
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cont++;
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save_and_next(); spaceleft--;
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}
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continue;
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case ']':
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save_and_next(); spaceleft--;
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if (current == ']')
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{
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if (cont == 0) return STRING;
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cont--;
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save_and_next(); spaceleft--;
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}
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continue;
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case '\n':
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lua_linenumber++; /* goes through */
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default:
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save_and_next(); spaceleft--;
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}
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}
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}
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int luaY_lex (void)
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{
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float a;
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static int linelasttoken = 0;
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if (lua_debug)
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luaI_codedebugline(linelasttoken);
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linelasttoken = lua_linenumber;
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while (1)
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{
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yytextLast = yytext;
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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': linelasttoken = ++lua_linenumber;
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case ' ':
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case '\r': /* CR: to avoid problems with DOS/Windows */
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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, "debug") == 0)
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{
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luaY_lval.vInt = 1;
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return DEBUG;
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}
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else if (lua_strcmp(yytext, "nodebug") == 0)
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{
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luaY_lval.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 '-'; /* else goes through */
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case '#':
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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
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{
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save_and_next(); /* pass the second '[' */
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if (read_long_string() == WRONGTOKEN)
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return WRONGTOKEN;
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save_and_next(); /* pass the second ']' */
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*(yytextLast-2) = 0; /* erases ']]' */
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luaY_lval.vWord = luaI_findconstantbyname(yytext+2);
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return STRING;
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}
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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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int spaceleft = textsize - (yytextLast - yytext);
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next(); /* skip the delimiter */
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while (current != del)
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{
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if (spaceleft <= 2) /* may read more than 1 char in one cicle */
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{
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growtext();
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spaceleft = textsize - (yytextLast - yytext);
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}
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spaceleft--;
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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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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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luaY_lval.vWord = luaI_findconstantbyname(yytext);
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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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Word 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);
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if (res) return res;
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luaY_lval.pNode = lua_constcreate(yytext);
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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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luaY_lval.vFloat = a;
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return NUMBER;
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}
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case U_and: case U_do: case U_else: case U_elseif: case U_end:
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case U_function: case U_if: case U_local: case U_nil: case U_not:
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case U_or: case U_repeat: case U_return: case U_then:
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case U_until: case U_while:
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{
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int old = current;
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next();
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return reserved[old-U_and].token;
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}
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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[0];
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}
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}
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}
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}
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