mirror of
https://github.com/lua/lua
synced 2024-11-27 15:19:36 +03:00
411 lines
11 KiB
C
411 lines
11 KiB
C
/*
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** $Id: llex.c,v 1.115 2002/10/22 16:45:52 roberto Exp roberto $
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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 <ctype.h>
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#include <string.h>
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#include "lua.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 "lzio.h"
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#define next(LS) (LS->current = zgetc(LS->z))
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/* ORDER RESERVED */
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static const char *const token2string [] = {
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"and", "break", "do", "else", "elseif",
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"end", "false", "for", "function", "if",
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"in", "local", "nil", "not", "or", "repeat",
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"return", "then", "true", "until", "while", "*name",
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"..", "...", "==", ">=", "<=", "~=",
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"*number", "*string", "<eof>"
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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, token2string[i]);
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luaS_fix(ts); /* reserved words are never collected */
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lua_assert(strlen(token2string[i])+1 <= TOKEN_LEN);
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ts->tsv.reserved = cast(lu_byte, i+1); /* reserved word */
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}
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}
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#define MAXSRC 80
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void luaX_checklimit (LexState *ls, int val, int limit, const char *msg) {
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if (val > limit) {
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msg = luaO_pushfstring(ls->L, "too many %s (limit=%d)", msg, limit);
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luaX_syntaxerror(ls, msg);
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}
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}
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static void luaX_error (LexState *ls, const char *s, const char *token) {
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lua_State *L = ls->L;
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char buff[MAXSRC];
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luaO_chunkid(buff, getstr(ls->source), MAXSRC);
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luaO_pushfstring(L, "%s:%d: %s near `%s'", buff, ls->linenumber, s, token);
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luaD_throw(L, LUA_ERRSYNTAX);
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}
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void luaX_syntaxerror (LexState *ls, const char *msg) {
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const char *lasttoken;
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switch (ls->t.token) {
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case TK_NAME:
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lasttoken = getstr(ls->t.seminfo.ts);
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break;
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case TK_STRING:
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case TK_NUMBER:
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lasttoken = luaZ_buffer(ls->buff);
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break;
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default:
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lasttoken = luaX_token2str(ls, ls->t.token);
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break;
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}
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luaX_error(ls, msg, lasttoken);
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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 == (char)token);
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return luaO_pushfstring(ls->L, "%c", token);
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}
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else
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return token2string[token-FIRST_RESERVED];
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}
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static void luaX_lexerror (LexState *ls, const char *s, int token) {
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if (token == TK_EOS)
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luaX_error(ls, s, luaX_token2str(ls, token));
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else
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luaX_error(ls, s, luaZ_buffer(ls->buff));
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}
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static void inclinenumber (LexState *LS) {
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next(LS); /* skip `\n' */
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++LS->linenumber;
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luaX_checklimit(LS, LS->linenumber, MAX_INT, "lines in a chunk");
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}
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void luaX_setinput (lua_State *L, LexState *LS, ZIO *z, TString *source) {
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LS->L = L;
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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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next(LS); /* read first char */
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if (LS->current == '#') {
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do { /* skip first line */
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next(LS);
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} while (LS->current != '\n' && LS->current != EOZ);
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}
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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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/* use buffer to store names, literal strings and numbers */
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/* extra space to allocate when growing buffer */
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#define EXTRABUFF 32
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/* maximum number of chars that can be read without checking buffer size */
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#define MAXNOCHECK 5
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#define checkbuffer(LS, len) \
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if (((len)+MAXNOCHECK)*sizeof(char) > luaZ_sizebuffer((LS)->buff)) \
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luaZ_openspace((LS)->L, (LS)->buff, (len)+EXTRABUFF)
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#define save(LS, c, l) \
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(luaZ_buffer((LS)->buff)[l++] = cast(char, c))
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#define save_and_next(LS, l) (save(LS, LS->current, l), next(LS))
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static size_t readname (LexState *LS) {
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size_t l = 0;
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checkbuffer(LS, l);
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do {
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checkbuffer(LS, l);
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save_and_next(LS, l);
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} while (isalnum(LS->current) || LS->current == '_');
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save(LS, '\0', l);
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return l-1;
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}
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/* LUA_NUMBER */
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static void read_numeral (LexState *LS, int comma, SemInfo *seminfo) {
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size_t l = 0;
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checkbuffer(LS, l);
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if (comma) save(LS, '.', l);
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while (isdigit(LS->current)) {
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checkbuffer(LS, l);
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save_and_next(LS, l);
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}
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if (LS->current == '.') {
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save_and_next(LS, l);
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if (LS->current == '.') {
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save_and_next(LS, l);
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save(LS, '\0', l);
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luaX_lexerror(LS,
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"ambiguous syntax (decimal point x string concatenation)",
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TK_NUMBER);
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}
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}
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while (isdigit(LS->current)) {
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checkbuffer(LS, l);
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save_and_next(LS, l);
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}
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if (LS->current == 'e' || LS->current == 'E') {
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save_and_next(LS, l); /* read `E' */
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if (LS->current == '+' || LS->current == '-')
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save_and_next(LS, l); /* optional exponent sign */
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while (isdigit(LS->current)) {
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checkbuffer(LS, l);
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save_and_next(LS, l);
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}
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}
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save(LS, '\0', l);
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if (!luaO_str2d(luaZ_buffer(LS->buff), &seminfo->r))
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luaX_lexerror(LS, "malformed number", TK_NUMBER);
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}
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static void read_long_string (LexState *LS, SemInfo *seminfo) {
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int cont = 0;
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size_t l = 0;
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checkbuffer(LS, l);
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save(LS, '[', l); /* save first `[' */
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save_and_next(LS, l); /* pass the second `[' */
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if (LS->current == '\n') /* string starts with a newline? */
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inclinenumber(LS); /* skip it */
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for (;;) {
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checkbuffer(LS, l);
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switch (LS->current) {
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case EOZ:
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save(LS, '\0', l);
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luaX_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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save_and_next(LS, l);
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if (LS->current == '[') {
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cont++;
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save_and_next(LS, l);
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}
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continue;
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case ']':
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save_and_next(LS, l);
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if (LS->current == ']') {
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if (cont == 0) goto endloop;
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cont--;
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save_and_next(LS, l);
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}
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continue;
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case '\n':
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save(LS, '\n', l);
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inclinenumber(LS);
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if (!seminfo) l = 0; /* reset buffer to avoid wasting space */
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continue;
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default:
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save_and_next(LS, l);
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}
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} endloop:
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save_and_next(LS, l); /* skip the second `]' */
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save(LS, '\0', l);
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if (seminfo)
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seminfo->ts = luaS_newlstr(LS->L, luaZ_buffer(LS->buff) + 2, l - 5);
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}
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static void read_string (LexState *LS, int del, SemInfo *seminfo) {
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size_t l = 0;
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checkbuffer(LS, l);
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save_and_next(LS, l);
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while (LS->current != del) {
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checkbuffer(LS, l);
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switch (LS->current) {
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case EOZ:
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save(LS, '\0', l);
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luaX_lexerror(LS, "unfinished string", TK_EOS);
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break; /* to avoid warnings */
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case '\n':
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save(LS, '\0', l);
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luaX_lexerror(LS, "unfinished string", TK_STRING);
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break; /* to avoid warnings */
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case '\\':
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next(LS); /* do not save the `\' */
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switch (LS->current) {
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case 'a': save(LS, '\a', l); next(LS); break;
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case 'b': save(LS, '\b', l); next(LS); break;
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case 'f': save(LS, '\f', l); next(LS); break;
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case 'n': save(LS, '\n', l); next(LS); break;
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case 'r': save(LS, '\r', l); next(LS); break;
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case 't': save(LS, '\t', l); next(LS); break;
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case 'v': save(LS, '\v', l); next(LS); break;
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case '\n': save(LS, '\n', l); inclinenumber(LS); break;
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case EOZ: break; /* will raise an error next loop */
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default: {
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if (!isdigit(LS->current))
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save_and_next(LS, l); /* handles \\, \", \', and \? */
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else { /* \xxx */
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int c = 0;
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int i = 0;
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do {
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c = 10*c + (LS->current-'0');
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next(LS);
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} while (++i<3 && isdigit(LS->current));
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if (c > UCHAR_MAX) {
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save(LS, '\0', l);
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luaX_lexerror(LS, "escape sequence too large", TK_STRING);
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}
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save(LS, c, l);
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}
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}
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}
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break;
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default:
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save_and_next(LS, l);
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}
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}
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save_and_next(LS, l); /* skip delimiter */
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save(LS, '\0', l);
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seminfo->ts = luaS_newlstr(LS->L, luaZ_buffer(LS->buff) + 1, l - 3);
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}
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int luaX_lex (LexState *LS, SemInfo *seminfo) {
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for (;;) {
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switch (LS->current) {
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case '\n': {
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inclinenumber(LS);
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continue;
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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 is a comment */
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next(LS);
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if (LS->current == '[' && (next(LS), LS->current == '['))
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read_long_string(LS, NULL); /* long comment */
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else /* short comment */
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while (LS->current != '\n' && LS->current != EOZ)
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next(LS);
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continue;
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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 {
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read_long_string(LS, seminfo);
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return TK_STRING;
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}
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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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case '\'': {
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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 '.': {
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next(LS);
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if (LS->current == '.') {
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next(LS);
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if (LS->current == '.') {
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next(LS);
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return TK_DOTS; /* ... */
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}
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else return TK_CONCAT; /* .. */
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}
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else if (!isdigit(LS->current)) return '.';
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else {
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read_numeral(LS, 1, seminfo);
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return TK_NUMBER;
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}
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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 (isspace(LS->current)) {
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next(LS);
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continue;
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}
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else if (isdigit(LS->current)) {
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read_numeral(LS, 0, seminfo);
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return TK_NUMBER;
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}
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else if (isalpha(LS->current) || LS->current == '_') {
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/* identifier or reserved word */
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size_t l = readname(LS);
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TString *ts = luaS_newlstr(LS->L, luaZ_buffer(LS->buff), l);
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if (ts->tsv.reserved > 0) /* reserved word? */
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return ts->tsv.reserved - 1 + FIRST_RESERVED;
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seminfo->ts = ts;
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return TK_NAME;
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}
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else {
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int c = LS->current;
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if (iscntrl(c))
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luaX_error(LS, "invalid control char",
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luaO_pushfstring(LS->L, "char(%d)", c));
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next(LS);
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return c; /* single-char tokens (+ - / ...) */
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}
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}
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}
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}
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}
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#undef next
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