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1087
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1 /*
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2 ** $Id: llex.c,v 2.61 2012/01/23 23:05:51 roberto Exp $
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3 ** Lexical Analyzer
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4 ** See Copyright Notice in lua.h
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5 */
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6
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7
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8 #include <locale.h>
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9 #include <string.h>
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10
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11 #define llex_c
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12 #define LUA_CORE
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13
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14 #include "lua.h"
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15
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16 #include "lctype.h"
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17 #include "ldo.h"
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18 #include "llex.h"
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19 #include "lobject.h"
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20 #include "lparser.h"
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21 #include "lstate.h"
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22 #include "lstring.h"
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23 #include "ltable.h"
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24 #include "lzio.h"
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25
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26
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27
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28 #define next(ls) (ls->current = zgetc(ls->z))
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29
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30
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31
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32 #define currIsNewline(ls) (ls->current == '\n' || ls->current == '\r')
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33
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34
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35 /* ORDER RESERVED */
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36 static const char *const luaX_tokens [] = {
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37 "and", "break", "do", "else", "elseif",
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38 "end", "false", "for", "function", "goto", "if",
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39 "in", "local", "nil", "not", "or", "repeat",
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40 "return", "then", "true", "until", "while",
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41 "..", "...", "==", ">=", "<=", "~=", "::", "<eof>",
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42 "<number>", "<name>", "<string>"
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43 };
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44
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45
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46 #define save_and_next(ls) (save(ls, ls->current), next(ls))
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47
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48
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49 static l_noret lexerror (LexState *ls, const char *msg, int token);
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50
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51
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52 static void save (LexState *ls, int c) {
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53 Mbuffer *b = ls->buff;
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54 if (luaZ_bufflen(b) + 1 > luaZ_sizebuffer(b)) {
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55 size_t newsize;
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56 if (luaZ_sizebuffer(b) >= MAX_SIZET/2)
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57 lexerror(ls, "lexical element too long", 0);
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58 newsize = luaZ_sizebuffer(b) * 2;
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59 luaZ_resizebuffer(ls->L, b, newsize);
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60 }
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61 b->buffer[luaZ_bufflen(b)++] = cast(char, c);
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62 }
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63
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64
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65 void luaX_init (lua_State *L) {
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66 int i;
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67 for (i=0; i<NUM_RESERVED; i++) {
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68 TString *ts = luaS_new(L, luaX_tokens[i]);
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69 luaS_fix(ts); /* reserved words are never collected */
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70 ts->tsv.extra = cast_byte(i+1); /* reserved word */
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71 }
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72 }
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73
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74
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75 const char *luaX_token2str (LexState *ls, int token) {
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76 if (token < FIRST_RESERVED) {
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77 lua_assert(token == cast(unsigned char, token));
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78 return (lisprint(token)) ? luaO_pushfstring(ls->L, LUA_QL("%c"), token) :
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79 luaO_pushfstring(ls->L, "char(%d)", token);
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80 }
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81 else {
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82 const char *s = luaX_tokens[token - FIRST_RESERVED];
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83 if (token < TK_EOS)
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84 return luaO_pushfstring(ls->L, LUA_QS, s);
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85 else
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86 return s;
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87 }
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88 }
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89
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90
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91 static const char *txtToken (LexState *ls, int token) {
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92 switch (token) {
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93 case TK_NAME:
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94 case TK_STRING:
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95 case TK_NUMBER:
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96 save(ls, '\0');
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97 return luaO_pushfstring(ls->L, LUA_QS, luaZ_buffer(ls->buff));
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98 default:
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99 return luaX_token2str(ls, token);
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100 }
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101 }
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102
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103
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104 static l_noret lexerror (LexState *ls, const char *msg, int token) {
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105 char buff[LUA_IDSIZE];
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106 luaO_chunkid(buff, getstr(ls->source), LUA_IDSIZE);
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107 msg = luaO_pushfstring(ls->L, "%s:%d: %s", buff, ls->linenumber, msg);
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108 if (token)
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109 luaO_pushfstring(ls->L, "%s near %s", msg, txtToken(ls, token));
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110 luaD_throw(ls->L, LUA_ERRSYNTAX);
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111 }
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112
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113
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114 l_noret luaX_syntaxerror (LexState *ls, const char *msg) {
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115 lexerror(ls, msg, ls->t.token);
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116 }
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117
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118
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119 /*
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120 ** creates a new string and anchors it in function's table so that
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121 ** it will not be collected until the end of the function's compilation
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122 ** (by that time it should be anchored in function's prototype)
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123 */
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124 TString *luaX_newstring (LexState *ls, const char *str, size_t l) {
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125 lua_State *L = ls->L;
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126 TValue *o; /* entry for `str' */
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127 TString *ts = luaS_newlstr(L, str, l); /* create new string */
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128 setsvalue2s(L, L->top++, ts); /* temporarily anchor it in stack */
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129 o = luaH_set(L, ls->fs->h, L->top - 1);
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130 if (ttisnil(o)) { /* not in use yet? (see 'addK') */
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131 /* boolean value does not need GC barrier;
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132 table has no metatable, so it does not need to invalidate cache */
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133 setbvalue(o, 1); /* t[string] = true */
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134 luaC_checkGC(L);
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135 }
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136 L->top--; /* remove string from stack */
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137 return ts;
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138 }
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139
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140
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141 /*
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142 ** increment line number and skips newline sequence (any of
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143 ** \n, \r, \n\r, or \r\n)
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144 */
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145 static void inclinenumber (LexState *ls) {
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146 int old = ls->current;
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147 lua_assert(currIsNewline(ls));
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148 next(ls); /* skip `\n' or `\r' */
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149 if (currIsNewline(ls) && ls->current != old)
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150 next(ls); /* skip `\n\r' or `\r\n' */
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151 if (++ls->linenumber >= MAX_INT)
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152 luaX_syntaxerror(ls, "chunk has too many lines");
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153 }
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154
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155
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156 void luaX_setinput (lua_State *L, LexState *ls, ZIO *z, TString *source,
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157 int firstchar) {
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158 ls->decpoint = '.';
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159 ls->L = L;
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160 ls->current = firstchar;
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161 ls->lookahead.token = TK_EOS; /* no look-ahead token */
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162 ls->z = z;
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163 ls->fs = NULL;
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164 ls->linenumber = 1;
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165 ls->lastline = 1;
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166 ls->source = source;
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167 ls->envn = luaS_new(L, LUA_ENV); /* create env name */
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168 luaS_fix(ls->envn); /* never collect this name */
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169 luaZ_resizebuffer(ls->L, ls->buff, LUA_MINBUFFER); /* initialize buffer */
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170 }
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171
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172
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173
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174 /*
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175 ** =======================================================
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176 ** LEXICAL ANALYZER
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177 ** =======================================================
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178 */
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179
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180
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181
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182 static int check_next (LexState *ls, const char *set) {
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183 if (ls->current == '\0' || !strchr(set, ls->current))
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184 return 0;
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185 save_and_next(ls);
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186 return 1;
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187 }
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188
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189
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190 /*
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191 ** change all characters 'from' in buffer to 'to'
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192 */
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193 static void buffreplace (LexState *ls, char from, char to) {
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194 size_t n = luaZ_bufflen(ls->buff);
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195 char *p = luaZ_buffer(ls->buff);
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196 while (n--)
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197 if (p[n] == from) p[n] = to;
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198 }
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199
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200
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201 #if !defined(getlocaledecpoint)
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202 #define getlocaledecpoint() (localeconv()->decimal_point[0])
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203 #endif
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204
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205
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206 #define buff2d(b,e) luaO_str2d(luaZ_buffer(b), luaZ_bufflen(b) - 1, e)
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207
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208 /*
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209 ** in case of format error, try to change decimal point separator to
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210 ** the one defined in the current locale and check again
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211 */
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212 static void trydecpoint (LexState *ls, SemInfo *seminfo) {
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213 char old = ls->decpoint;
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214 ls->decpoint = getlocaledecpoint();
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215 buffreplace(ls, old, ls->decpoint); /* try new decimal separator */
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216 if (!buff2d(ls->buff, &seminfo->r)) {
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217 /* format error with correct decimal point: no more options */
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218 buffreplace(ls, ls->decpoint, '.'); /* undo change (for error message) */
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219 lexerror(ls, "malformed number", TK_NUMBER);
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220 }
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221 }
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222
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223
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224 /* LUA_NUMBER */
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225 /*
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226 ** this function is quite liberal in what it accepts, as 'luaO_str2d'
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227 ** will reject ill-formed numerals.
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228 */
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229 static void read_numeral (LexState *ls, SemInfo *seminfo) {
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230 const char *expo = "Ee";
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231 int first = ls->current;
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232 lua_assert(lisdigit(ls->current));
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233 save_and_next(ls);
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234 if (first == '0' && check_next(ls, "Xx")) /* hexadecimal? */
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235 expo = "Pp";
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236 for (;;) {
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237 if (check_next(ls, expo)) /* exponent part? */
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238 check_next(ls, "+-"); /* optional exponent sign */
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239 if (lisxdigit(ls->current) || ls->current == '.')
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240 save_and_next(ls);
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241 else break;
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242 }
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243 save(ls, '\0');
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244 buffreplace(ls, '.', ls->decpoint); /* follow locale for decimal point */
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245 if (!buff2d(ls->buff, &seminfo->r)) /* format error? */
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246 trydecpoint(ls, seminfo); /* try to update decimal point separator */
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247 }
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248
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249
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250 /*
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251 ** skip a sequence '[=*[' or ']=*]' and return its number of '='s or
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252 ** -1 if sequence is malformed
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253 */
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254 static int skip_sep (LexState *ls) {
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255 int count = 0;
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256 int s = ls->current;
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257 lua_assert(s == '[' || s == ']');
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258 save_and_next(ls);
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259 while (ls->current == '=') {
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260 save_and_next(ls);
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261 count++;
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262 }
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263 return (ls->current == s) ? count : (-count) - 1;
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264 }
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265
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266
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267 static void read_long_string (LexState *ls, SemInfo *seminfo, int sep) {
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268 save_and_next(ls); /* skip 2nd `[' */
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269 if (currIsNewline(ls)) /* string starts with a newline? */
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270 inclinenumber(ls); /* skip it */
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271 for (;;) {
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272 switch (ls->current) {
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273 case EOZ:
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274 lexerror(ls, (seminfo) ? "unfinished long string" :
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275 "unfinished long comment", TK_EOS);
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276 break; /* to avoid warnings */
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277 case ']': {
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278 if (skip_sep(ls) == sep) {
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279 save_and_next(ls); /* skip 2nd `]' */
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280 goto endloop;
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281 }
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282 break;
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283 }
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284 case '\n': case '\r': {
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285 save(ls, '\n');
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286 inclinenumber(ls);
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287 if (!seminfo) luaZ_resetbuffer(ls->buff); /* avoid wasting space */
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288 break;
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289 }
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290 default: {
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291 if (seminfo) save_and_next(ls);
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292 else next(ls);
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293 }
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294 }
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295 } endloop:
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296 if (seminfo)
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297 seminfo->ts = luaX_newstring(ls, luaZ_buffer(ls->buff) + (2 + sep),
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298 luaZ_bufflen(ls->buff) - 2*(2 + sep));
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299 }
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300
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301
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302 static void escerror (LexState *ls, int *c, int n, const char *msg) {
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303 int i;
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304 luaZ_resetbuffer(ls->buff); /* prepare error message */
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305 save(ls, '\\');
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306 for (i = 0; i < n && c[i] != EOZ; i++)
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307 save(ls, c[i]);
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308 lexerror(ls, msg, TK_STRING);
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309 }
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310
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311
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312 static int readhexaesc (LexState *ls) {
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313 int c[3], i; /* keep input for error message */
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314 int r = 0; /* result accumulator */
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315 c[0] = 'x'; /* for error message */
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316 for (i = 1; i < 3; i++) { /* read two hexa digits */
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317 c[i] = next(ls);
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318 if (!lisxdigit(c[i]))
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319 escerror(ls, c, i + 1, "hexadecimal digit expected");
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320 r = (r << 4) + luaO_hexavalue(c[i]);
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321 }
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322 return r;
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323 }
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324
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325
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326 static int readdecesc (LexState *ls) {
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327 int c[3], i;
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328 int r = 0; /* result accumulator */
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329 for (i = 0; i < 3 && lisdigit(ls->current); i++) { /* read up to 3 digits */
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330 c[i] = ls->current;
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331 r = 10*r + c[i] - '0';
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332 next(ls);
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333 }
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334 if (r > UCHAR_MAX)
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335 escerror(ls, c, i, "decimal escape too large");
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336 return r;
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337 }
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338
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339
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340 static void read_string (LexState *ls, int del, SemInfo *seminfo) {
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341 save_and_next(ls); /* keep delimiter (for error messages) */
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342 while (ls->current != del) {
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343 switch (ls->current) {
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344 case EOZ:
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345 lexerror(ls, "unfinished string", TK_EOS);
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346 break; /* to avoid warnings */
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347 case '\n':
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348 case '\r':
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349 lexerror(ls, "unfinished string", TK_STRING);
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350 break; /* to avoid warnings */
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351 case '\\': { /* escape sequences */
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352 int c; /* final character to be saved */
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353 next(ls); /* do not save the `\' */
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354 switch (ls->current) {
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355 case 'a': c = '\a'; goto read_save;
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356 case 'b': c = '\b'; goto read_save;
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357 case 'f': c = '\f'; goto read_save;
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358 case 'n': c = '\n'; goto read_save;
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359 case 'r': c = '\r'; goto read_save;
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360 case 't': c = '\t'; goto read_save;
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361 case 'v': c = '\v'; goto read_save;
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362 case 'x': c = readhexaesc(ls); goto read_save;
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363 case '\n': case '\r':
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364 inclinenumber(ls); c = '\n'; goto only_save;
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365 case '\\': case '\"': case '\'':
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366 c = ls->current; goto read_save;
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367 case EOZ: goto no_save; /* will raise an error next loop */
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368 case 'z': { /* zap following span of spaces */
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369 next(ls); /* skip the 'z' */
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370 while (lisspace(ls->current)) {
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371 if (currIsNewline(ls)) inclinenumber(ls);
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372 else next(ls);
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373 }
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374 goto no_save;
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375 }
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376 default: {
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377 if (!lisdigit(ls->current))
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378 escerror(ls, &ls->current, 1, "invalid escape sequence");
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379 /* digital escape \ddd */
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380 c = readdecesc(ls);
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381 goto only_save;
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382 }
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383 }
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384 read_save: next(ls); /* read next character */
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385 only_save: save(ls, c); /* save 'c' */
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386 no_save: break;
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387 }
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388 default:
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389 save_and_next(ls);
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390 }
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391 }
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392 save_and_next(ls); /* skip delimiter */
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393 seminfo->ts = luaX_newstring(ls, luaZ_buffer(ls->buff) + 1,
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394 luaZ_bufflen(ls->buff) - 2);
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395 }
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396
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397
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398 static int llex (LexState *ls, SemInfo *seminfo) {
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399 luaZ_resetbuffer(ls->buff);
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400 for (;;) {
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401 switch (ls->current) {
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402 case '\n': case '\r': { /* line breaks */
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403 inclinenumber(ls);
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404 break;
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405 }
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406 case ' ': case '\f': case '\t': case '\v': { /* spaces */
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407 next(ls);
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408 break;
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409 }
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410 case '-': { /* '-' or '--' (comment) */
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411 next(ls);
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412 if (ls->current != '-') return '-';
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413 /* else is a comment */
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414 next(ls);
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415 if (ls->current == '[') { /* long comment? */
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416 int sep = skip_sep(ls);
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417 luaZ_resetbuffer(ls->buff); /* `skip_sep' may dirty the buffer */
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418 if (sep >= 0) {
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419 read_long_string(ls, NULL, sep); /* skip long comment */
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420 luaZ_resetbuffer(ls->buff); /* previous call may dirty the buff. */
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421 break;
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422 }
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423 }
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424 /* else short comment */
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425 while (!currIsNewline(ls) && ls->current != EOZ)
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426 next(ls); /* skip until end of line (or end of file) */
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427 break;
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428 }
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429 case '[': { /* long string or simply '[' */
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430 int sep = skip_sep(ls);
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431 if (sep >= 0) {
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432 read_long_string(ls, seminfo, sep);
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433 return TK_STRING;
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434 }
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435 else if (sep == -1) return '[';
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436 else lexerror(ls, "invalid long string delimiter", TK_STRING);
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437 }
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438 case '=': {
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439 next(ls);
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440 if (ls->current != '=') return '=';
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441 else { next(ls); return TK_EQ; }
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442 }
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443 case '<': {
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444 next(ls);
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445 if (ls->current != '=') return '<';
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446 else { next(ls); return TK_LE; }
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447 }
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448 case '>': {
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449 next(ls);
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450 if (ls->current != '=') return '>';
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451 else { next(ls); return TK_GE; }
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452 }
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453 case '~': {
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454 next(ls);
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455 if (ls->current != '=') return '~';
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456 else { next(ls); return TK_NE; }
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457 }
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458 case ':': {
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459 next(ls);
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460 if (ls->current != ':') return ':';
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461 else { next(ls); return TK_DBCOLON; }
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462 }
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463 case '"': case '\'': { /* short literal strings */
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464 read_string(ls, ls->current, seminfo);
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465 return TK_STRING;
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466 }
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467 case '.': { /* '.', '..', '...', or number */
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468 save_and_next(ls);
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469 if (check_next(ls, ".")) {
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470 if (check_next(ls, "."))
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471 return TK_DOTS; /* '...' */
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472 else return TK_CONCAT; /* '..' */
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473 }
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474 else if (!lisdigit(ls->current)) return '.';
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475 /* else go through */
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476 }
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477 case '0': case '1': case '2': case '3': case '4':
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478 case '5': case '6': case '7': case '8': case '9': {
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479 read_numeral(ls, seminfo);
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480 return TK_NUMBER;
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481 }
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482 case EOZ: {
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483 return TK_EOS;
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484 }
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485 default: {
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486 if (lislalpha(ls->current)) { /* identifier or reserved word? */
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487 TString *ts;
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488 do {
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489 save_and_next(ls);
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490 } while (lislalnum(ls->current));
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491 ts = luaX_newstring(ls, luaZ_buffer(ls->buff),
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|
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492 luaZ_bufflen(ls->buff));
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493 seminfo->ts = ts;
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494 if (isreserved(ts)) /* reserved word? */
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495 return ts->tsv.extra - 1 + FIRST_RESERVED;
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496 else {
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497 return TK_NAME;
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498 }
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499 }
|
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500 else { /* single-char tokens (+ - / ...) */
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501 int c = ls->current;
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|
502 next(ls);
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503 return c;
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504 }
|
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505 }
|
|
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506 }
|
|
|
507 }
|
|
|
508 }
|
|
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509
|
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510
|
|
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511 void luaX_next (LexState *ls) {
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512 ls->lastline = ls->linenumber;
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|
513 if (ls->lookahead.token != TK_EOS) { /* is there a look-ahead token? */
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514 ls->t = ls->lookahead; /* use this one */
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515 ls->lookahead.token = TK_EOS; /* and discharge it */
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516 }
|
|
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517 else
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|
518 ls->t.token = llex(ls, &ls->t.seminfo); /* read next token */
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|
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519 }
|
|
|
520
|
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521
|
|
|
522 int luaX_lookahead (LexState *ls) {
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|
|
523 lua_assert(ls->lookahead.token == TK_EOS);
|
|
|
524 ls->lookahead.token = llex(ls, &ls->lookahead.seminfo);
|
|
|
525 return ls->lookahead.token;
|
|
|
526 }
|
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527
|
