commit 0810bc707f98f05a2d598e6a00cb33280d16cf89
parent c3b73cbeb8c1f5588b0f516264ae34778975e6d6
Author: Roberto Ierusalimschy <roberto@inf.puc-rio.br>
Date: Mon, 10 Apr 2000 16:20:52 -0300
new syntax: |label|
Diffstat:
| M | lparser.c | | | 143 | ++++++++++++++++++++++++++++++++++++++++++++++++++++--------------------------- |
1 file changed, 94 insertions(+), 49 deletions(-)
diff --git a/lparser.c b/lparser.c
@@ -1,5 +1,5 @@
/*
-** $Id: lparser.c,v 1.78 2000/04/07 13:13:11 roberto Exp roberto $
+** $Id: lparser.c,v 1.79 2000/04/07 19:35:20 roberto Exp roberto $
** LL(1) Parser and code generator for Lua
** See Copyright Notice in lua.h
*/
@@ -36,6 +36,7 @@ typedef struct Constdesc {
typedef struct Breaklabel {
struct Breaklabel *previous; /* chain */
+ TString *label;
int breaklist;
int stacklevel;
} Breaklabel;
@@ -171,6 +172,14 @@ static TString *str_checkname (LexState *ls) {
}
+static TString *optionalname (LexState *ls) {
+ if (ls->token == TK_NAME)
+ return str_checkname(ls);
+ else
+ return NULL;
+}
+
+
static void luaI_registerlocalvar (LexState *ls, TString *varname,
int line) {
FuncState *fs = ls->fs;
@@ -317,6 +326,7 @@ static int getvarname (LexState *ls, expdesc *var) {
static void enterbreak (FuncState *fs, Breaklabel *bl) {
bl->stacklevel = fs->stacklevel;
+ bl->label = NULL;
bl->breaklist = NO_JUMP;
bl->previous = fs->bl;
fs->bl = bl;
@@ -330,6 +340,20 @@ static void leavebreak (FuncState *fs, Breaklabel *bl) {
}
+static Breaklabel *findlabel (FuncState *fs, TString *name) {
+ Breaklabel *bl;
+ for (bl=fs->bl; bl; bl=bl->previous) {
+ if (bl->label == name)
+ return bl;
+ }
+ if (name) /* label not found: choose appropriate error message */
+ luaX_syntaxerror(fs->ls, "break not inside given label", name->str);
+ else
+ luaK_error(fs->ls, "break not inside while or repeat loop");
+ return NULL; /* to avoid warnings */
+}
+
+
static void func_onstack (LexState *ls, FuncState *func) {
FuncState *fs = ls->fs;
Proto *f = fs->f;
@@ -419,7 +443,7 @@ static int explist1 (LexState *ls) {
expr(ls, &v);
n++;
}
- luaK_tostack(ls, &v, 0);
+ luaK_tostack(ls, &v, 0); /* keep open number of values of last expression */
return n;
}
@@ -427,12 +451,12 @@ static int explist1 (LexState *ls) {
static int explist (LexState *ls) {
/* explist -> [ explist1 ] */
switch (ls->token) {
- case TK_ELSE: case TK_ELSEIF: case TK_END: case TK_UNTIL:
- case TK_EOS: case ';': case ')':
- return 0; /* empty list */
-
- default:
+ case TK_NUMBER: case TK_STRING: case TK_NIL: case '{':
+ case TK_FUNCTION: case '(': case TK_NAME: case '%':
+ case TK_NOT: case '-': /* first `expr' */
return explist1(ls);
+ default:
+ return 0; /* empty list */
}
}
@@ -998,44 +1022,73 @@ static void namestat (LexState *ls) {
}
+static void retstat (LexState *ls) {
+ /* stat -> RETURN explist */
+ FuncState *fs = ls->fs;
+ setline_and_next(ls); /* skip RETURN */
+ explist(ls);
+ luaK_code1(fs, OP_RETURN, ls->fs->nlocalvar);
+ fs->stacklevel = fs->nlocalvar; /* removes all temp values */
+}
+
+
+static void breakstat (LexState *ls) {
+ /* stat -> BREAK [NAME] */
+ FuncState *fs = ls->fs;
+ Breaklabel *bl;
+ int currentlevel = fs->stacklevel;
+ setline_and_next(ls); /* skip BREAK */
+ bl = findlabel(fs, optionalname(ls));
+ luaK_adjuststack(fs, currentlevel - bl->stacklevel);
+ luaK_concat(fs, &bl->breaklist, luaK_jump(fs));
+ fs->stacklevel = currentlevel;
+}
+
+
static int stat (LexState *ls) {
int line = ls->linenumber; /* may be needed for error messages */
switch (ls->token) {
case TK_IF: /* stat -> ifstat */
ifstat(ls, line);
- break;
+ return 1;
case TK_WHILE: /* stat -> whilestat */
whilestat(ls, line);
- break;
+ return 1;
- case TK_DO: { /* stat -> DO block END */
+ case TK_DO: /* stat -> DO block END */
setline_and_next(ls); /* skip DO */
block(ls);
check_END(ls, TK_DO, line);
- break;
- }
+ return 1;
case TK_REPEAT: /* stat -> repeatstat */
repeatstat(ls, line);
- break;
+ return 1;
case TK_FUNCTION: /* stat -> funcstat */
funcstat(ls, line);
- break;
+ return 1;
case TK_LOCAL: /* stat -> localstat */
localstat(ls);
- break;
+ return 1;
case TK_NAME: case '%': /* stat -> namestat */
namestat(ls);
- break;
+ return 1;
+
+ case TK_RETURN: /* stat -> retstat */
+ retstat(ls);
+ return 2; /* must be last statement */
+
+ case TK_BREAK: /* stat -> breakstat */
+ breakstat(ls);
+ return 2; /* must be last statement */
default:
return 0; /* no statement */
}
- return 1;
}
@@ -1092,44 +1145,36 @@ static void body (LexState *ls, int needself, int line) {
}
-static void ret (LexState *ls) {
- /* ret -> [RETURN explist sc | BREAK sc] */
- FuncState *fs = ls->fs;
- switch (ls->token) {
- case TK_RETURN: {
- setline_and_next(ls); /* skip RETURN */
- explist(ls);
- luaK_code1(fs, OP_RETURN, ls->fs->nlocalvar);
- fs->stacklevel = fs->nlocalvar; /* removes all temp values */
- optional(ls, ';');
- break;
- }
- case TK_BREAK: {
- Breaklabel *bl = fs->bl;
- int currentlevel = fs->stacklevel;
- if (bl == NULL)
- luaK_error(ls, "break not inside while or repeat loop");
-
- setline_and_next(ls); /* skip BREAK */
- luaK_adjuststack(fs, currentlevel - bl->stacklevel);
- luaK_concat(fs, &bl->breaklist, luaK_jump(fs));
- optional(ls, ';');
- fs->stacklevel = currentlevel;
- break;
- }
+/* }====================================================================== */
+
+
+static void label (LexState *ls, Breaklabel *bl) {
+ /* label -> [ '|' NAME '|' ] */
+ if (optional(ls, '|')) {
+ enterbreak(ls->fs, bl);
+ bl->label = str_checkname(ls);
+ check(ls, '|');
}
+ else
+ bl->label = NULL; /* there is no label */
}
-/* }====================================================================== */
-
static void chunk (LexState *ls) {
- /* chunk -> { stat [;] } ret */
- while (stat(ls)) {
+ /* chunk -> { [label] stat [';'] } */
+ Breaklabel bl;
+ int a;
+ do {
+ label(ls, &bl);
+ a = stat(ls);
+ if (a != 0)
+ optional(ls, ';');
+ else if (bl.label)
+ luaK_error(ls, "label without a statement");
LUA_ASSERT(ls->L, ls->fs->stacklevel == ls->fs->nlocalvar,
"stack size != # local vars");
- optional(ls, ';');
- }
- ret(ls); /* optional return */
+ if (bl.label)
+ leavebreak(ls->fs, &bl);
+ } while (a == 1);
}
