mirror of
https://github.com/lua/lua
synced 2024-12-14 06:47:15 +03:00
350 lines
8.9 KiB
C
350 lines
8.9 KiB
C
/*
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** $Id: llex.c,v 1.67 2000/08/09 19:16:57 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 <stdio.h>
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#include <string.h>
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#include "lua.h"
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#include "lauxlib.h"
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#include "llex.h"
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#include "lmem.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 "luadebug.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 save(L, c) luaL_addchar(L, c)
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#define save_and_next(L, LS) (save(L, LS->current), next(LS))
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/* ORDER RESERVED */
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static const char *const token2string [] = {
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"and", "break", "do", "else", "elseif", "end", "for",
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"function", "if", "local", "nil", "not", "or", "repeat", "return", "then",
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"until", "while", "", "..", "...", "==", ">=", "<=", "~=", "", "", "<eof>"};
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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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ts->marked = (unsigned char)(RESERVEDMARK+i); /* 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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char buff[100];
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sprintf(buff, "too many %.50s (limit=%d)", msg, limit);
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luaX_error(ls, buff, ls->t.token);
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}
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}
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void luaX_syntaxerror (LexState *ls, const char *s, const char *token) {
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char buff[MAXSRC];
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luaL_chunkid(buff, ls->source->str, sizeof(buff));
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luaL_verror(ls->L, "%.100s;\n last token read: `%.50s' at line %d in %.80s",
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s, token, ls->linenumber, buff);
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}
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void luaX_error (LexState *ls, const char *s, int token) {
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char buff[TOKEN_LEN];
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luaX_token2str(token, buff);
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if (buff[0] == '\0') {
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save(ls->L, '\0');
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luaX_syntaxerror(ls, s, luaL_buffer(ls->L));
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}
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else
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luaX_syntaxerror(ls, s, buff);
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}
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void luaX_token2str (int token, char *s) {
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if (token < 256) {
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s[0] = (char)token;
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s[1] = '\0';
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}
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else
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strcpy(s, token2string[token-FIRST_RESERVED]);
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}
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static void luaX_invalidchar (LexState *ls, int c) {
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char buff[8];
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sprintf(buff, "0x%02X", c);
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luaX_syntaxerror(ls, "invalid control char", buff);
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}
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static const char *readname (lua_State *L, LexState *LS) {
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luaL_resetbuffer(L);
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do {
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save_and_next(L, LS);
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} while (isalnum(LS->current) || LS->current == '_');
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save(L, '\0');
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return L->Mbuffer+L->Mbuffbase;
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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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static void read_long_string (lua_State *L, LexState *LS) {
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int cont = 0;
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for (;;) {
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switch (LS->current) {
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case EOZ:
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luaX_error(LS, "unfinished long string", TK_STRING);
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break; /* to avoid warnings */
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case '[':
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save_and_next(L, LS);
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if (LS->current == '[') {
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cont++;
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save_and_next(L, LS);
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}
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continue;
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case ']':
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save_and_next(L, LS);
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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(L, LS);
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}
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continue;
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case '\n':
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save(L, '\n');
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inclinenumber(LS);
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continue;
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default:
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save_and_next(L, LS);
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}
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} endloop:
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save_and_next(L, LS); /* skip the second ']' */
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LS->t.seminfo.ts = luaS_newlstr(L, L->Mbuffer+(L->Mbuffbase+2),
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L->Mbuffnext-L->Mbuffbase-4);
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}
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static void read_string (lua_State *L, LexState *LS, int del) {
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save_and_next(L, LS);
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while (LS->current != del) {
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switch (LS->current) {
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case EOZ: case '\n':
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luaX_error(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(L, '\a'); next(LS); break;
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case 'b': save(L, '\b'); next(LS); break;
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case 'f': save(L, '\f'); next(LS); break;
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case 'n': save(L, '\n'); next(LS); break;
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case 'r': save(L, '\r'); next(LS); break;
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case 't': save(L, '\t'); next(LS); break;
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case 'v': save(L, '\v'); next(LS); break;
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case '\n': save(L, '\n'); inclinenumber(LS); break;
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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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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 != (unsigned char)c)
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luaX_error(LS, "escape sequence too large", TK_STRING);
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save(L, c);
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break;
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}
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default: /* handles \\, \", \', and \? */
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save(L, LS->current);
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next(LS);
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}
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break;
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default:
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save_and_next(L, LS);
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}
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}
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save_and_next(L, LS); /* skip delimiter */
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LS->t.seminfo.ts = luaS_newlstr(L, L->Mbuffer+(L->Mbuffbase+1),
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L->Mbuffnext-L->Mbuffbase-2);
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}
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int luaX_lex (LexState *LS) {
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lua_State *L = LS->L;
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for (;;) {
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switch (LS->current) {
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case ' ': case '\t': case '\r': /* `\r' to avoid problems with DOS */
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next(LS);
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continue;
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case '\n':
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inclinenumber(LS);
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continue;
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case '$':
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luaX_error(LS, "unexpected `$' (pragmas are no longer supported)", '$');
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break;
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case '-':
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next(LS);
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if (LS->current != '-') return '-';
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do { next(LS); } while (LS->current != '\n' && LS->current != EOZ);
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continue;
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case '[':
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luaL_resetbuffer(L);
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save_and_next(L, LS);
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if (LS->current != '[') return '[';
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else {
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save_and_next(L, LS); /* pass the second '[' */
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read_long_string(L, LS);
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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 != '=') return '=';
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else { next(LS); return TK_EQ; }
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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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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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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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case '"':
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case '\'':
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luaL_resetbuffer(L);
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read_string(L, LS, LS->current);
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return TK_STRING;
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case '.':
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luaL_resetbuffer(L);
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save_and_next(L, 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 goto fraction; /* LS->current is a digit */
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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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luaL_resetbuffer(L);
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do {
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save_and_next(L, LS);
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} while (isdigit(LS->current));
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if (LS->current == '.') {
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save_and_next(L, LS);
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if (LS->current == '.') {
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save(L, '.');
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luaX_error(LS, "ambiguous syntax"
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" (decimal point x string concatenation)", TK_NUMBER);
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}
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}
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fraction: /* LUA_NUMBER */
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while (isdigit(LS->current))
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save_and_next(L, LS);
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if (LS->current == 'e' || LS->current == 'E') {
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save_and_next(L, LS); /* read 'E' */
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if (LS->current == '+' || LS->current == '-')
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save_and_next(L, LS); /* optional exponent sign */
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while (isdigit(LS->current))
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save_and_next(L, LS);
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}
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save(L, '\0');
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if (!luaO_str2d(L->Mbuffer+L->Mbuffbase, &LS->t.seminfo.r))
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luaX_error(LS, "malformed number", TK_NUMBER);
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return TK_NUMBER;
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case EOZ:
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return TK_EOS;
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case '_': goto tname;
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default:
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if (!isalpha(LS->current)) {
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int c = LS->current;
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if (iscntrl(c))
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luaX_invalidchar(LS, c);
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next(LS);
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return c;
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}
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tname: { /* identifier or reserved word */
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TString *ts = luaS_new(L, readname(L, LS));
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if (ts->marked >= RESERVEDMARK) /* reserved word? */
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return ts->marked-RESERVEDMARK+FIRST_RESERVED;
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LS->t.seminfo.ts = ts;
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return TK_NAME;
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}
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}
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}
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}
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