528 lines
15 KiB
C
528 lines
15 KiB
C
/*
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** $Id: llex.c,v 2.61 2012/01/23 23:05:51 roberto Exp $
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** Lexical Analyzer
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** See Copyright Notice in lua.h
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*/
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#include <locale.h>
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#include <string.h>
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#define llex_c
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#define LUA_CORE
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#include "lua.h"
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#include "lctype.h"
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#include "ldo.h"
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#include "llex.h"
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#include "lobject.h"
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#include "lparser.h"
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#include "lstate.h"
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#include "lstring.h"
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#include "ltable.h"
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#include "lzio.h"
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#define next(ls) (ls->current = zgetc(ls->z))
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#define currIsNewline(ls) (ls->current == '\n' || ls->current == '\r')
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/* ORDER RESERVED */
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static const char *const luaX_tokens [] = {
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"and", "break", "do", "else", "elseif",
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"end", "false", "for", "function", "goto", "if",
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"in", "local", "nil", "not", "or", "repeat",
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"return", "then", "true", "until", "while",
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"..", "...", "==", ">=", "<=", "~=", "::", "<eof>",
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"<number>", "<name>", "<string>"
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};
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#define save_and_next(ls) (save(ls, ls->current), next(ls))
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static l_noret lexerror (LexState *ls, const char *msg, int token);
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static void save (LexState *ls, int c) {
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Mbuffer *b = ls->buff;
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if (luaZ_bufflen(b) + 1 > luaZ_sizebuffer(b)) {
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size_t newsize;
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if (luaZ_sizebuffer(b) >= MAX_SIZET/2)
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lexerror(ls, "lexical element too long", 0);
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newsize = luaZ_sizebuffer(b) * 2;
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luaZ_resizebuffer(ls->L, b, newsize);
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}
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b->buffer[luaZ_bufflen(b)++] = cast(char, c);
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}
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void luaX_init (lua_State *L) {
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int i;
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for (i=0; i<NUM_RESERVED; i++) {
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TString *ts = luaS_new(L, luaX_tokens[i]);
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luaS_fix(ts); /* reserved words are never collected */
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ts->tsv.extra = cast_byte(i+1); /* reserved word */
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}
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}
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const char *luaX_token2str (LexState *ls, int token) {
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if (token < FIRST_RESERVED) {
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lua_assert(token == cast(unsigned char, token));
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return (lisprint(token)) ? luaO_pushfstring(ls->L, LUA_QL("%c"), token) :
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luaO_pushfstring(ls->L, "char(%d)", token);
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}
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else {
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const char *s = luaX_tokens[token - FIRST_RESERVED];
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if (token < TK_EOS)
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return luaO_pushfstring(ls->L, LUA_QS, s);
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else
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return s;
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}
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}
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static const char *txtToken (LexState *ls, int token) {
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switch (token) {
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case TK_NAME:
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case TK_STRING:
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case TK_NUMBER:
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save(ls, '\0');
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return luaO_pushfstring(ls->L, LUA_QS, luaZ_buffer(ls->buff));
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default:
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return luaX_token2str(ls, token);
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}
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}
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static l_noret lexerror (LexState *ls, const char *msg, int token) {
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char buff[LUA_IDSIZE];
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luaO_chunkid(buff, getstr(ls->source), LUA_IDSIZE);
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msg = luaO_pushfstring(ls->L, "%s:%d: %s", buff, ls->linenumber, msg);
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if (token)
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luaO_pushfstring(ls->L, "%s near %s", msg, txtToken(ls, token));
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luaD_throw(ls->L, LUA_ERRSYNTAX);
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}
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l_noret luaX_syntaxerror (LexState *ls, const char *msg) {
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lexerror(ls, msg, ls->t.token);
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}
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/*
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** creates a new string and anchors it in function's table so that
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** it will not be collected until the end of the function's compilation
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** (by that time it should be anchored in function's prototype)
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*/
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TString *luaX_newstring (LexState *ls, const char *str, size_t l) {
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lua_State *L = ls->L;
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TValue *o; /* entry for `str' */
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TString *ts = luaS_newlstr(L, str, l); /* create new string */
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setsvalue2s(L, L->top++, ts); /* temporarily anchor it in stack */
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o = luaH_set(L, ls->fs->h, L->top - 1);
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if (ttisnil(o)) { /* not in use yet? (see 'addK') */
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/* boolean value does not need GC barrier;
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table has no metatable, so it does not need to invalidate cache */
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setbvalue(o, 1); /* t[string] = true */
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luaC_checkGC(L);
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}
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L->top--; /* remove string from stack */
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return ts;
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}
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/*
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** increment line number and skips newline sequence (any of
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** \n, \r, \n\r, or \r\n)
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*/
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static void inclinenumber (LexState *ls) {
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int old = ls->current;
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lua_assert(currIsNewline(ls));
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next(ls); /* skip `\n' or `\r' */
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if (currIsNewline(ls) && ls->current != old)
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next(ls); /* skip `\n\r' or `\r\n' */
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if (++ls->linenumber >= MAX_INT)
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luaX_syntaxerror(ls, "chunk has too many lines");
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}
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void luaX_setinput (lua_State *L, LexState *ls, ZIO *z, TString *source,
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int firstchar) {
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ls->decpoint = '.';
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ls->L = L;
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ls->current = firstchar;
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ls->lookahead.token = TK_EOS; /* no look-ahead token */
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ls->z = z;
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ls->fs = NULL;
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ls->linenumber = 1;
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ls->lastline = 1;
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ls->source = source;
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ls->envn = luaS_new(L, LUA_ENV); /* create env name */
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luaS_fix(ls->envn); /* never collect this name */
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luaZ_resizebuffer(ls->L, ls->buff, LUA_MINBUFFER); /* initialize buffer */
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}
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/*
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** =======================================================
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** LEXICAL ANALYZER
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** =======================================================
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*/
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static int check_next (LexState *ls, const char *set) {
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if (ls->current == '\0' || !strchr(set, ls->current))
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return 0;
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save_and_next(ls);
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return 1;
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}
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/*
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** change all characters 'from' in buffer to 'to'
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*/
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static void buffreplace (LexState *ls, char from, char to) {
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size_t n = luaZ_bufflen(ls->buff);
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char *p = luaZ_buffer(ls->buff);
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while (n--)
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if (p[n] == from) p[n] = to;
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}
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#if !defined(getlocaledecpoint)
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#define getlocaledecpoint() (localeconv()->decimal_point[0])
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#endif
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#define buff2d(b,e) luaO_str2d(luaZ_buffer(b), luaZ_bufflen(b) - 1, e)
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/*
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** in case of format error, try to change decimal point separator to
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** the one defined in the current locale and check again
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*/
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static void trydecpoint (LexState *ls, SemInfo *seminfo) {
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char old = ls->decpoint;
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ls->decpoint = getlocaledecpoint();
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buffreplace(ls, old, ls->decpoint); /* try new decimal separator */
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if (!buff2d(ls->buff, &seminfo->r)) {
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/* format error with correct decimal point: no more options */
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buffreplace(ls, ls->decpoint, '.'); /* undo change (for error message) */
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lexerror(ls, "malformed number", TK_NUMBER);
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}
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}
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/* LUA_NUMBER */
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/*
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** this function is quite liberal in what it accepts, as 'luaO_str2d'
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** will reject ill-formed numerals.
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*/
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static void read_numeral (LexState *ls, SemInfo *seminfo) {
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const char *expo = "Ee";
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int first = ls->current;
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lua_assert(lisdigit(ls->current));
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save_and_next(ls);
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if (first == '0' && check_next(ls, "Xx")) /* hexadecimal? */
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expo = "Pp";
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for (;;) {
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if (check_next(ls, expo)) /* exponent part? */
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check_next(ls, "+-"); /* optional exponent sign */
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if (lisxdigit(ls->current) || ls->current == '.')
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save_and_next(ls);
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else break;
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}
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save(ls, '\0');
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buffreplace(ls, '.', ls->decpoint); /* follow locale for decimal point */
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if (!buff2d(ls->buff, &seminfo->r)) /* format error? */
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trydecpoint(ls, seminfo); /* try to update decimal point separator */
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}
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/*
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** skip a sequence '[=*[' or ']=*]' and return its number of '='s or
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** -1 if sequence is malformed
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*/
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static int skip_sep (LexState *ls) {
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int count = 0;
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int s = ls->current;
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lua_assert(s == '[' || s == ']');
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save_and_next(ls);
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while (ls->current == '=') {
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save_and_next(ls);
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count++;
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}
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return (ls->current == s) ? count : (-count) - 1;
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}
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static void read_long_string (LexState *ls, SemInfo *seminfo, int sep) {
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save_and_next(ls); /* skip 2nd `[' */
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if (currIsNewline(ls)) /* string starts with a newline? */
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inclinenumber(ls); /* skip it */
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for (;;) {
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switch (ls->current) {
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case EOZ:
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lexerror(ls, (seminfo) ? "unfinished long string" :
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"unfinished long comment", TK_EOS);
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break; /* to avoid warnings */
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case ']': {
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if (skip_sep(ls) == sep) {
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save_and_next(ls); /* skip 2nd `]' */
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goto endloop;
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}
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break;
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}
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case '\n': case '\r': {
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save(ls, '\n');
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inclinenumber(ls);
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if (!seminfo) luaZ_resetbuffer(ls->buff); /* avoid wasting space */
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break;
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}
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default: {
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if (seminfo) save_and_next(ls);
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else next(ls);
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}
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}
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} endloop:
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if (seminfo)
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seminfo->ts = luaX_newstring(ls, luaZ_buffer(ls->buff) + (2 + sep),
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luaZ_bufflen(ls->buff) - 2*(2 + sep));
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}
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static void escerror (LexState *ls, int *c, int n, const char *msg) {
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int i;
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luaZ_resetbuffer(ls->buff); /* prepare error message */
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save(ls, '\\');
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for (i = 0; i < n && c[i] != EOZ; i++)
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save(ls, c[i]);
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lexerror(ls, msg, TK_STRING);
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}
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static int readhexaesc (LexState *ls) {
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int c[3], i; /* keep input for error message */
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int r = 0; /* result accumulator */
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c[0] = 'x'; /* for error message */
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for (i = 1; i < 3; i++) { /* read two hexa digits */
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c[i] = next(ls);
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if (!lisxdigit(c[i]))
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escerror(ls, c, i + 1, "hexadecimal digit expected");
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r = (r << 4) + luaO_hexavalue(c[i]);
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}
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return r;
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}
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static int readdecesc (LexState *ls) {
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int c[3], i;
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int r = 0; /* result accumulator */
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for (i = 0; i < 3 && lisdigit(ls->current); i++) { /* read up to 3 digits */
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c[i] = ls->current;
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r = 10*r + c[i] - '0';
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next(ls);
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}
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if (r > UCHAR_MAX)
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escerror(ls, c, i, "decimal escape too large");
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return r;
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}
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static void read_string (LexState *ls, int del, SemInfo *seminfo) {
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save_and_next(ls); /* keep delimiter (for error messages) */
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while (ls->current != del) {
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switch (ls->current) {
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case EOZ:
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lexerror(ls, "unfinished string", TK_EOS);
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break; /* to avoid warnings */
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case '\n':
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case '\r':
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lexerror(ls, "unfinished string", TK_STRING);
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break; /* to avoid warnings */
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case '\\': { /* escape sequences */
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int c; /* final character to be saved */
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next(ls); /* do not save the `\' */
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switch (ls->current) {
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case 'a': c = '\a'; goto read_save;
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case 'b': c = '\b'; goto read_save;
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case 'f': c = '\f'; goto read_save;
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case 'n': c = '\n'; goto read_save;
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case 'r': c = '\r'; goto read_save;
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case 't': c = '\t'; goto read_save;
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case 'v': c = '\v'; goto read_save;
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case 'x': c = readhexaesc(ls); goto read_save;
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case '\n': case '\r':
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inclinenumber(ls); c = '\n'; goto only_save;
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case '\\': case '\"': case '\'':
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c = ls->current; goto read_save;
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case EOZ: goto no_save; /* will raise an error next loop */
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case 'z': { /* zap following span of spaces */
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next(ls); /* skip the 'z' */
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while (lisspace(ls->current)) {
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if (currIsNewline(ls)) inclinenumber(ls);
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else next(ls);
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}
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goto no_save;
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}
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default: {
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if (!lisdigit(ls->current))
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escerror(ls, &ls->current, 1, "invalid escape sequence");
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/* digital escape \ddd */
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c = readdecesc(ls);
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goto only_save;
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}
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}
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read_save: next(ls); /* read next character */
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only_save: save(ls, c); /* save 'c' */
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no_save: break;
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}
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default:
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save_and_next(ls);
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}
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}
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save_and_next(ls); /* skip delimiter */
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seminfo->ts = luaX_newstring(ls, luaZ_buffer(ls->buff) + 1,
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luaZ_bufflen(ls->buff) - 2);
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}
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static int llex (LexState *ls, SemInfo *seminfo) {
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luaZ_resetbuffer(ls->buff);
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for (;;) {
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switch (ls->current) {
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case '\n': case '\r': { /* line breaks */
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inclinenumber(ls);
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break;
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}
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case ' ': case '\f': case '\t': case '\v': { /* spaces */
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next(ls);
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break;
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}
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case '-': { /* '-' or '--' (comment) */
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next(ls);
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if (ls->current != '-') return '-';
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/* else is a comment */
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next(ls);
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if (ls->current == '[') { /* long comment? */
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int sep = skip_sep(ls);
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luaZ_resetbuffer(ls->buff); /* `skip_sep' may dirty the buffer */
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if (sep >= 0) {
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read_long_string(ls, NULL, sep); /* skip long comment */
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luaZ_resetbuffer(ls->buff); /* previous call may dirty the buff. */
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break;
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}
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}
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/* else short comment */
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while (!currIsNewline(ls) && ls->current != EOZ)
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next(ls); /* skip until end of line (or end of file) */
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break;
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}
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case '[': { /* long string or simply '[' */
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int sep = skip_sep(ls);
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if (sep >= 0) {
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read_long_string(ls, seminfo, sep);
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return TK_STRING;
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}
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else if (sep == -1) return '[';
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else lexerror(ls, "invalid long string delimiter", TK_STRING);
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}
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case '=': {
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next(ls);
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if (ls->current != '=') return '=';
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else { next(ls); return TK_EQ; }
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}
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case '<': {
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next(ls);
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if (ls->current != '=') return '<';
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else { next(ls); return TK_LE; }
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}
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case '>': {
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next(ls);
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if (ls->current != '=') return '>';
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else { next(ls); return TK_GE; }
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}
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case '~': {
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next(ls);
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if (ls->current != '=') return '~';
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else { next(ls); return TK_NE; }
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}
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case ':': {
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next(ls);
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if (ls->current != ':') return ':';
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else { next(ls); return TK_DBCOLON; }
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}
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case '"': case '\'': { /* short literal strings */
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read_string(ls, ls->current, seminfo);
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return TK_STRING;
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}
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case '.': { /* '.', '..', '...', or number */
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save_and_next(ls);
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if (check_next(ls, ".")) {
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if (check_next(ls, "."))
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return TK_DOTS; /* '...' */
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else return TK_CONCAT; /* '..' */
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}
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else if (!lisdigit(ls->current)) return '.';
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/* else go through */
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}
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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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read_numeral(ls, seminfo);
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return TK_NUMBER;
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}
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case EOZ: {
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return TK_EOS;
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}
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default: {
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if (lislalpha(ls->current)) { /* identifier or reserved word? */
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TString *ts;
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do {
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save_and_next(ls);
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} while (lislalnum(ls->current));
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ts = luaX_newstring(ls, luaZ_buffer(ls->buff),
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luaZ_bufflen(ls->buff));
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seminfo->ts = ts;
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if (isreserved(ts)) /* reserved word? */
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return ts->tsv.extra - 1 + FIRST_RESERVED;
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else {
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return TK_NAME;
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}
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}
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else { /* single-char tokens (+ - / ...) */
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int c = ls->current;
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|
next(ls);
|
|
return c;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
|
|
void luaX_next (LexState *ls) {
|
|
ls->lastline = ls->linenumber;
|
|
if (ls->lookahead.token != TK_EOS) { /* is there a look-ahead token? */
|
|
ls->t = ls->lookahead; /* use this one */
|
|
ls->lookahead.token = TK_EOS; /* and discharge it */
|
|
}
|
|
else
|
|
ls->t.token = llex(ls, &ls->t.seminfo); /* read next token */
|
|
}
|
|
|
|
|
|
int luaX_lookahead (LexState *ls) {
|
|
lua_assert(ls->lookahead.token == TK_EOS);
|
|
ls->lookahead.token = llex(ls, &ls->lookahead.seminfo);
|
|
return ls->lookahead.token;
|
|
}
|
|
|