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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 ** Lexical Analyzer
** See Copyright Notice in lua.h ** 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; ** Check whether current char is in set 'set' (with two chars) and
save_and_next(ls); ** saves it
return 1; */
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; int first = ls->current;
lua_assert(lisdigit(ls->current)); lua_assert(lisdigit(ls->current));
save_and_next(ls); save_and_next(ls);
if (first == '0' && check_next(ls, "Xx")) /* hexadecimal? */ if (first == '0' && check_next2(ls, "xX")) /* hexadecimal? */
expo = "Pp"; expo = "Pp";
for (;;) { for (;;) {
if (check_next(ls, expo)) /* exponent part? */ if (check_next2(ls, expo)) /* exponent part? */
check_next(ls, "+-"); /* optional exponent sign */ check_next2(ls, "-+"); /* optional exponent sign */
if (lisxdigit(ls->current)) if (lisxdigit(ls->current))
save_and_next(ls); save_and_next(ls);
else if (ls->current == '.') else if (ls->current == '.')
@@ -490,35 +504,35 @@ static int llex (LexState *ls, SemInfo *seminfo) {
} }
case '=': { case '=': {
next(ls); next(ls);
if (ls->current != '=') return '='; if (check_next1(ls, '=')) return TK_EQ;
else { next(ls); return TK_EQ; } else return '=';
} }
case '<': { case '<': {
next(ls); next(ls);
if (ls->current == '=') { next(ls); return TK_LE; } if (check_next1(ls, '=')) return TK_LE;
if (ls->current == '<') { next(ls); return TK_SHL; } else if (check_next1(ls, '<')) return TK_SHL;
return '<'; else return '<';
} }
case '>': { case '>': {
next(ls); next(ls);
if (ls->current == '=') { next(ls); return TK_GE; } if (check_next1(ls, '=')) return TK_GE;
if (ls->current == '>') { next(ls); return TK_SHR; } else if (check_next1(ls, '>')) return TK_SHR;
return '>'; else return '>';
} }
case '/': { case '/': {
next(ls); next(ls);
if (ls->current != '/') return '/'; if (check_next1(ls, '/')) return TK_IDIV;
else { next(ls); return TK_IDIV; } else return '/';
} }
case '~': { case '~': {
next(ls); next(ls);
if (ls->current != '=') return '~'; if (check_next1(ls, '=')) return TK_NE;
else { next(ls); return TK_NE; } else return '~';
} }
case ':': { case ':': {
next(ls); next(ls);
if (ls->current != ':') return ':'; if (check_next1(ls, ':')) return TK_DBCOLON;
else { next(ls); return TK_DBCOLON; } else return ':';
} }
case '"': case '\'': { /* short literal strings */ case '"': case '\'': { /* short literal strings */
read_string(ls, ls->current, seminfo); read_string(ls, ls->current, seminfo);
@@ -526,8 +540,8 @@ static int llex (LexState *ls, SemInfo *seminfo) {
} }
case '.': { /* '.', '..', '...', or number */ case '.': { /* '.', '..', '...', or number */
save_and_next(ls); save_and_next(ls);
if (check_next(ls, ".")) { if (check_next1(ls, '.')) {
if (check_next(ls, ".")) if (check_next1(ls, '.'))
return TK_DOTS; /* '...' */ return TK_DOTS; /* '...' */
else return TK_CONCAT; /* '..' */ else return TK_CONCAT; /* '..' */
} }