MIRROR: javascript for 🐜's, a tiny runtime with big ambitions
preserve TCO behavior in semicolon-free style
+52
-4
+14
-4
src/ant.c
+14
-4
src/ant.c
···
5157
5157
static inline uint8_t lookahead(struct js *js) {
5158
5158
uint8_t old = js->tok, tok = 0;
5159
5159
uint8_t old_consumed = js->consumed;
5160
+
5160
5161
jsoff_t pos = js->pos;
5162
+
jsoff_t toff = js->toff;
5163
+
jsoff_t tlen = js->tlen;
5164
+
5165
+
bool had_newline = js->had_newline;
5161
5166
int stream_pos = js->token_stream_pos;
5162
5167
5163
5168
js->consumed = 1;
5164
5169
tok = next(js);
5170
+
5165
5171
js->pos = pos;
5166
5172
js->tok = old;
5173
+
js->toff = toff;
5174
+
js->tlen = tlen;
5175
+
5176
+
js->had_newline = had_newline;
5167
5177
js->consumed = old_consumed;
5168
5178
js->token_stream_pos = stream_pos;
5169
5179
···
10928
10938
uint8_t flags = js->flags;
10929
10939
js->consumed = 1;
10930
10940
if (js_truthy(js, resolveprop(js, res))) {
10931
-
res = js_ternary(js);
10941
+
res = js_assignment(js);
10932
10942
js->flags |= F_NOEXEC;
10933
10943
EXPECT(TOK_COLON, js->flags = flags);
10934
-
js_ternary(js);
10944
+
js_assignment(js);
10935
10945
js->flags = flags;
10936
10946
} else {
10937
10947
js->flags |= F_NOEXEC;
10938
-
js_ternary(js);
10948
+
js_assignment(js);
10939
10949
EXPECT(TOK_COLON, js->flags = flags);
10940
10950
js->flags = flags;
10941
-
res = js_ternary(js);
10951
+
res = js_assignment(js);
10942
10952
}
10943
10953
}
10944
10954
return res;
+38
tests/test_tco_asi.js
+38
tests/test_tco_asi.js
···
1
+
// Regression: verify TCO behavior is preserved with semicolon-free (ASI) style
2
+
// and that newline-after-return keeps standard ASI semantics.
3
+
4
+
function fail(msg) {
5
+
console.log("FAIL:", msg)
6
+
process.exit(1)
7
+
}
8
+
9
+
function assertEq(actual, expected, msg) {
10
+
if (actual !== expected) fail(msg + " (got " + actual + ", expected " + expected + ")")
11
+
}
12
+
13
+
console.log("=== TCO + ASI Regression ===")
14
+
15
+
// Semicolon-free style: this should still be optimized as a tail call.
16
+
function countDownAsi(n) {
17
+
if (n === 0) return 0
18
+
return countDownAsi(n - 1)
19
+
}
20
+
21
+
assertEq(countDownAsi(100000), 0, "tail recursion with ASI should complete")
22
+
23
+
// Tail recursion in ternary form with no trailing semicolons.
24
+
function sumAsi(n, acc = 0) {
25
+
return n === 0 ? acc : sumAsi(n - 1, acc + n)
26
+
}
27
+
28
+
assertEq(sumAsi(100000), 5000050000, "tail recursion in ternary should complete")
29
+
30
+
// ASI rule check: newline after `return` ends the statement.
31
+
function returnNewlineAsi() {
32
+
return
33
+
42
34
+
}
35
+
36
+
if (returnNewlineAsi() !== undefined) fail("newline after return must produce undefined")
37
+
38
+
console.log("PASS")