cleaner code for 'if' construct

This commit is contained in:
Roberto Ierusalimschy 2011-08-25 10:45:24 -03:00
parent a8675966ec
commit 121dc8af66
1 changed files with 14 additions and 20 deletions

View File

@ -1,5 +1,5 @@
/*
** $Id: lparser.c,v 2.115 2011/07/27 18:09:01 roberto Exp roberto $
** $Id: lparser.c,v 2.116 2011/08/23 17:24:34 roberto Exp roberto $
** Lua Parser
** See Copyright Notice in lua.h
*/
@ -1360,38 +1360,32 @@ static void forstat (LexState *ls, int line) {
}
static int test_then_block (LexState *ls) {
static void test_then_block (LexState *ls, int *escapelist) {
/* test_then_block -> [IF | ELSEIF] cond THEN block */
FuncState *fs = ls->fs;
int condexit;
luaX_next(ls); /* skip IF or ELSEIF */
condexit = cond(ls);
condexit = cond(ls); /* 'if' condition */
checknext(ls, TK_THEN);
block(ls); /* `then' part */
return condexit;
if (ls->t.token == TK_ELSE ||
ls->t.token == TK_ELSEIF) /* followed by 'else'/'elseif'? */
luaK_concat(fs, escapelist, luaK_jump(fs)); /* must jump over it */
luaK_patchtohere(fs, condexit); /* 'if' condition jumps to here */
}
static void ifstat (LexState *ls, int line) {
/* ifstat -> IF cond THEN block {ELSEIF cond THEN block} [ELSE block] END */
FuncState *fs = ls->fs;
int flist;
int escapelist = NO_JUMP;
flist = test_then_block(ls); /* IF cond THEN block */
while (ls->t.token == TK_ELSEIF) {
luaK_concat(fs, &escapelist, luaK_jump(fs));
luaK_patchtohere(fs, flist);
flist = test_then_block(ls); /* ELSEIF cond THEN block */
}
if (ls->t.token == TK_ELSE) {
luaK_concat(fs, &escapelist, luaK_jump(fs));
luaK_patchtohere(fs, flist);
luaX_next(ls); /* skip ELSE (after patch, for correct line info) */
int escapelist = NO_JUMP; /* exit list for finished parts */
test_then_block(ls, &escapelist); /* IF cond THEN block */
while (ls->t.token == TK_ELSEIF)
test_then_block(ls, &escapelist); /* ELSEIF cond THEN block */
if (testnext(ls, TK_ELSE))
block(ls); /* `else' part */
}
else
luaK_concat(fs, &escapelist, flist);
luaK_patchtohere(fs, escapelist);
check_match(ls, TK_END, TK_IF, line);
luaK_patchtohere(fs, escapelist); /* patch escape list to 'if' end */
}