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small improvements concerning 'check_next'

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This commit is contained in:
Roberto Ierusalimschy 2014-05-21 12:22:02 -03:00
parent 8a0acf0898
commit c4eff10322
1 changed files with 39 additions and 25 deletions
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64
llex.c
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@ -1,5 +1,5 @@
/*
** $Id: llex.c,v 2.76 2014/05/01 18:18:06 roberto Exp roberto $
** $Id: llex.c,v 2.77 2014/05/11 14:45:43 roberto Exp roberto $
** Lexical Analyzer
** See Copyright Notice in lua.h
*/
@ -183,12 +183,26 @@ void luaX_setinput (lua_State *L, LexState *ls, ZIO *z, TString *source,
*/
static int check_next1 (LexState *ls, int c) {
if (ls->current == c) {
next(ls);
return 1;
}
else return 0;
}
static int check_next (LexState *ls, const char *set) {
if (ls->current == '\0' || !strchr(set, ls->current))
return 0;
save_and_next(ls);
return 1;
/*
** Check whether current char is in set 'set' (with two chars) and
** saves it
*/
static int check_next2 (LexState *ls, const char *set) {
lua_assert(set[2] == '\0');
if (ls->current == set[0] || ls->current == set[1]) {
save_and_next(ls);
return 1;
}
else return 0;
}
@ -239,11 +253,11 @@ static int read_numeral (LexState *ls, SemInfo *seminfo) {
int first = ls->current;
lua_assert(lisdigit(ls->current));
save_and_next(ls);
if (first == '0' && check_next(ls, "Xx")) /* hexadecimal? */
if (first == '0' && check_next2(ls, "xX")) /* hexadecimal? */
expo = "Pp";
for (;;) {
if (check_next(ls, expo)) /* exponent part? */
check_next(ls, "+-"); /* optional exponent sign */
if (check_next2(ls, expo)) /* exponent part? */
check_next2(ls, "-+"); /* optional exponent sign */
if (lisxdigit(ls->current))
save_and_next(ls);
else if (ls->current == '.')
@ -490,35 +504,35 @@ static int llex (LexState *ls, SemInfo *seminfo) {
}
case '=': {
next(ls);
if (ls->current != '=') return '=';
else { next(ls); return TK_EQ; }
if (check_next1(ls, '=')) return TK_EQ;
else return '=';
}
case '<': {
next(ls);
if (ls->current == '=') { next(ls); return TK_LE; }
if (ls->current == '<') { next(ls); return TK_SHL; }
return '<';
if (check_next1(ls, '=')) return TK_LE;
else if (check_next1(ls, '<')) return TK_SHL;
else return '<';
}
case '>': {
next(ls);
if (ls->current == '=') { next(ls); return TK_GE; }
if (ls->current == '>') { next(ls); return TK_SHR; }
return '>';
if (check_next1(ls, '=')) return TK_GE;
else if (check_next1(ls, '>')) return TK_SHR;
else return '>';
}
case '/': {
next(ls);
if (ls->current != '/') return '/';
else { next(ls); return TK_IDIV; }
if (check_next1(ls, '/')) return TK_IDIV;
else return '/';
}
case '~': {
next(ls);
if (ls->current != '=') return '~';
else { next(ls); return TK_NE; }
if (check_next1(ls, '=')) return TK_NE;
else return '~';
}
case ':': {
next(ls);
if (ls->current != ':') return ':';
else { next(ls); return TK_DBCOLON; }
if (check_next1(ls, ':')) return TK_DBCOLON;
else return ':';
}
case '"': case '\'': { /* short literal strings */
read_string(ls, ls->current, seminfo);
@ -526,8 +540,8 @@ static int llex (LexState *ls, SemInfo *seminfo) {
}
case '.': { /* '.', '..', '...', or number */
save_and_next(ls);
if (check_next(ls, ".")) {
if (check_next(ls, "."))
if (check_next1(ls, '.')) {
if (check_next1(ls, '.'))
return TK_DOTS; /* '...' */
else return TK_CONCAT; /* '..' */
}