mirror of
https://github.com/lua/lua
synced 2024-12-25 03:46:50 +03:00
471 lines
11 KiB
C
471 lines
11 KiB
C
char *rcs_lex = "$Id: lex.c,v 3.4 1997/06/11 18:56:02 roberto Exp roberto $";
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#include <ctype.h>
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#include <string.h>
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#include "auxlib.h"
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#include "luamem.h"
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#include "tree.h"
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#include "table.h"
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#include "lex.h"
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#include "inout.h"
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#include "luadebug.h"
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#include "parser.h"
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#define MINBUFF 250
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static int current; /* look ahead character */
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static ZIO *lex_z;
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#define next() (current = zgetc(lex_z))
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#define save(x) (yytext[tokensize++] = (x))
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#define save_and_next() (save(current), next())
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#define MAX_IFS 5
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/* "ifstate" keeps the state of each nested $if the lexical is dealing with. */
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static struct {
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int elsepart; /* true if its in the $else part */
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int condition; /* true if $if condition is true */
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int skip; /* true if part must be skiped */
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} ifstate[MAX_IFS];
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static int iflevel; /* level of nested $if's */
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void lua_setinput (ZIO *z)
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{
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current = '\n';
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lua_linenumber = 0;
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iflevel = 0;
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ifstate[0].skip = 0;
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ifstate[0].elsepart = 1; /* to avoid a free $else */
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lex_z = z;
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}
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static void luaI_auxsyntaxerror (char *s)
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{
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luaL_verror("%s;\n> at line %d in file %s",
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s, lua_linenumber, lua_parsedfile);
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}
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static void luaI_auxsynterrbf (char *s, char *token)
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{
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if (token[0] == 0)
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token = "<eof>";
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luaL_verror("%s;\n> last token read: \"%s\" at line %d in file %s",
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s, token, lua_linenumber, lua_parsedfile);
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}
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void luaI_syntaxerror (char *s)
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{
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luaI_auxsynterrbf(s, luaI_buffer(1));
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}
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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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void luaI_addReserved (void)
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{
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int i;
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for (i=0; i<RESERVEDSIZE; i++)
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{
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TaggedString *ts = lua_createstring(reserved[i].name);
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ts->marked = reserved[i].token; /* reserved word (always > 255) */
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}
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}
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/*
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** Pragma handling
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*/
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#define PRAGMASIZE 20
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static void skipspace (void)
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{
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while (current == ' ' || current == '\t') next();
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}
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static int checkcond (char *buff)
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{
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static char *opts[] = {"nil", "1"};
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int i = luaI_findstring(buff, opts);
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if (i >= 0) return i;
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else if (isalpha((unsigned char)buff[0]) || buff[0] == '_')
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return luaI_globaldefined(buff);
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else {
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luaI_auxsynterrbf("invalid $if condition", buff);
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return 0; /* to avoid warnings */
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}
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}
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static void readname (char *buff)
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{
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int i = 0;
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skipspace();
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while (isalnum((unsigned char)current) || current == '_') {
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if (i >= PRAGMASIZE) {
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buff[PRAGMASIZE] = 0;
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luaI_auxsynterrbf("pragma too long", buff);
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}
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buff[i++] = current;
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next();
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}
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buff[i] = 0;
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}
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static void inclinenumber (void);
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static void ifskip (void)
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{
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while (ifstate[iflevel].skip) {
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if (current == '\n')
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inclinenumber();
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else if (current == EOZ)
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luaI_auxsyntaxerror("input ends inside a $if");
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else next();
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}
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}
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static void inclinenumber (void)
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{
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static char *pragmas [] =
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{"debug", "nodebug", "endinput", "end", "ifnot", "if", "else", NULL};
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next(); /* skip '\n' */
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++lua_linenumber;
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if (current == '$') { /* is a pragma? */
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char buff[PRAGMASIZE+1];
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int ifnot = 0;
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int skip = ifstate[iflevel].skip;
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next(); /* skip $ */
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readname(buff);
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switch (luaI_findstring(buff, pragmas)) {
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case 0: /* debug */
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if (!skip) lua_debug = 1;
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break;
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case 1: /* nodebug */
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if (!skip) lua_debug = 0;
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break;
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case 2: /* endinput */
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if (!skip) {
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current = EOZ;
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iflevel = 0; /* to allow $endinput inside a $if */
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}
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break;
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case 3: /* end */
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if (iflevel-- == 0)
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luaI_auxsyntaxerror("unmatched $endif");
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break;
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case 4: /* ifnot */
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ifnot = 1;
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/* go through */
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case 5: /* if */
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if (iflevel == MAX_IFS-1)
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luaI_auxsyntaxerror("too many nested `$ifs'");
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readname(buff);
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iflevel++;
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ifstate[iflevel].elsepart = 0;
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ifstate[iflevel].condition = checkcond(buff) ? !ifnot : ifnot;
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ifstate[iflevel].skip = skip || !ifstate[iflevel].condition;
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break;
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case 6: /* else */
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if (ifstate[iflevel].elsepart)
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luaI_auxsyntaxerror("unmatched $else");
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ifstate[iflevel].elsepart = 1;
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ifstate[iflevel].skip =
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ifstate[iflevel-1].skip || ifstate[iflevel].condition;
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break;
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default:
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luaI_auxsynterrbf("invalid pragma", buff);
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}
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skipspace();
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if (current == '\n') /* pragma must end with a '\n' ... */
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inclinenumber();
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else if (current != EOZ) /* or eof */
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luaI_auxsyntaxerror("invalid pragma format");
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ifskip();
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}
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}
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static int read_long_string (char *yytext, int buffsize)
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{
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int cont = 0;
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int tokensize = 2; /* '[[' already stored */
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while (1)
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{
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if (buffsize-tokensize <= 2) /* may read more than 1 char in one cicle */
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yytext = luaI_buffer(buffsize *= 2);
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switch (current)
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{
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case EOZ:
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save(0);
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return WRONGTOKEN;
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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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cont++;
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save_and_next();
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}
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continue;
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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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if (cont == 0) goto endloop;
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cont--;
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save_and_next();
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}
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continue;
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case '\n':
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save('\n');
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inclinenumber();
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continue;
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default:
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save_and_next();
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}
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} endloop:
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save_and_next(); /* pass the second ']' */
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yytext[tokensize-2] = 0; /* erases ']]' */
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luaY_lval.vWord = luaI_findconstantbyname(yytext+2);
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yytext[tokensize-2] = ']'; /* restores ']]' */
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save(0);
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return STRING;
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}
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int luaY_lex (void)
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{
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static int linelasttoken = 0;
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double a;
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int buffsize = MINBUFF;
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char *yytext = luaI_buffer(buffsize);
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yytext[1] = yytext[2] = yytext[3] = 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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int tokensize = 0;
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switch (current)
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{
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case '\n':
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inclinenumber();
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linelasttoken = lua_linenumber;
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continue;
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case ' ': case '\t': case '\r': /* CR: to avoid problems with DOS */
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next();
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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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do { next(); } while (current != '\n' && current != EOZ);
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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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return read_long_string(yytext, buffsize);
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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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save_and_next();
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while (current != del)
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{
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if (buffsize-tokensize <= 2) /* may read more than 1 char in one cicle */
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yytext = luaI_buffer(buffsize *= 2);
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switch (current)
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{
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case EOZ:
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case '\n':
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save(0);
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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 '\n': save('\n'); inclinenumber(); break;
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default : save_and_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 delimiter */
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save(0);
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luaY_lval.vWord = luaI_findconstantbyname(yytext+1);
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tokensize--;
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save(del); save(0); /* restore delimiter */
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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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TaggedString *ts;
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do {
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save_and_next();
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} while (isalnum((unsigned char)current) || current == '_');
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save(0);
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ts = lua_createstring(yytext);
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if (ts->marked > 2)
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return ts->marked; /* reserved word */
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luaY_lval.pTStr = ts;
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ts->marked = 2; /* avoid GC */
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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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if (current == '.')
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{
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save_and_next();
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return DOTS; /* ... */
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}
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else return CONC; /* .. */
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}
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else if (!isdigit((unsigned char)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 {
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a=10.0*a+(current-'0');
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save_and_next();
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} while (isdigit((unsigned char)current));
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if (current == '.') {
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save_and_next();
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if (current == '.')
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luaI_syntaxerror(
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"ambiguous syntax (decimal point x string concatenation)");
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}
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fraction:
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{ double da=0.1;
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while (isdigit((unsigned char)current))
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{
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a+=(current-'0')*da;
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da/=10.0;
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save_and_next();
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}
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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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double 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((unsigned char)current)) {
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save(0); return WRONGTOKEN; }
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do {
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e=10.0*e+(current-'0');
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save_and_next();
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} while (isdigit((unsigned char)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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save(0);
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return NUMBER;
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}
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case EOZ:
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save(0);
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if (iflevel > 0)
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luaI_syntaxerror("missing $endif");
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return 0;
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default:
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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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