989e18b760
Replace the bare-paren tuple grammar with explicit, position-unambiguous
forms, mirroring how structs work:
type `(A, B)` -> `Tuple(A, B)` (named keeps `:`)
value `(a, b)` -> `.(a, b)` (named uses `=`)
typed (new) -> `Tuple(A, B).(a, b)` (like `Point.{...}`)
failable `-> (T, !)` -> `-> T !`
`-> (T1, T2, !)`-> `-> Tuple(T1, T2) !` (channel outside Tuple)
Bare `(...)` is now grouping only, everywhere; a comma in bare parens is a
hard error with a migration hint. Grouping, function types `(A, B) -> R`,
param lists, lambdas, and match bindings are unaffected.
`Tuple(...)` is strictly a TYPE in every position (including `size_of` /
`type_info` args); a tuple VALUE comes only from `.(...)` (anonymous) or
`Tuple(...).(...)` (explicitly typed). A bare `Tuple(1, 2)` is a tuple
type with non-type elements -> rejected.
The ~110 tuple-bearing corpus files were migrated with a one-shot
AST-aware migrator (the `sx migrate` tool from the prior commit, removed
here). New examples: 0130 (new syntax), 0131 (typed construction), 1060
(named-tuple failable return). 1116 golden updated for the new hint text.
61 lines
2.1 KiB
Plaintext
61 lines
2.1 KiB
Plaintext
// Path-sensitive value-slot liveness (ERR step E1.8). After `v, err := f()`, the
|
|
// value slot `v` is "live only where `err` is proven absent". Every read of `v`
|
|
// below sits on a path where the compiler can prove `err == null`:
|
|
//
|
|
// • `if !err { … v … }` — proven inside the guard
|
|
// • `if err { return } … v …` — proven on the fall-through
|
|
// • `if err { raise } … v …` — fall-through in a failable function
|
|
// • `if err { … } else { … v … }` — proven in the else branch
|
|
// • `!err and <reads v>` — short-circuit keeps the proof
|
|
//
|
|
// A bare tag-compare (`if err == error.X`) proves NOTHING about absence — see the
|
|
// rejection regression in 1047. (Regression for the E1.8 path-sensitive slice.)
|
|
|
|
#import "modules/std.sx";
|
|
|
|
E :: error { Bad, Empty }
|
|
|
|
parse :: (n: i32) -> i32 !E {
|
|
if n < 0 { raise error.Bad; }
|
|
if n == 0 { raise error.Empty; }
|
|
return n * 10;
|
|
}
|
|
|
|
// Early-return guard: the fall-through proves `err` absent.
|
|
guarded :: (n: i32) -> i32 {
|
|
v, err := parse(n);
|
|
if err { return -1; }
|
|
return v; // err proven absent here
|
|
}
|
|
|
|
// `if err { raise }` in a failable function: same fall-through proof.
|
|
relay :: (n: i32) -> i32 !E {
|
|
v, err := parse(n);
|
|
if err { raise err; }
|
|
return v + 1; // err proven absent here
|
|
}
|
|
|
|
main :: () -> i32 {
|
|
total : i32 = 0;
|
|
|
|
// (1) proven inside `if !err`
|
|
v1, e1 := parse(5);
|
|
if !e1 { total = total + v1; } // +50
|
|
|
|
// (2) proven in the else branch
|
|
v2, e2 := parse(7);
|
|
if e2 { total = total + 1; } else { total = total + v2; } // +70
|
|
|
|
// (3) short-circuit `&&` keeps the proof for the rhs
|
|
v3, e3 := parse(3);
|
|
if !e3 and v3 > 0 { total = total + v3; } // +30
|
|
|
|
// (4) early-return / raise helpers
|
|
total = total + guarded(4); // +40
|
|
total = total + guarded(-1); // -1
|
|
total = total + (relay(2) catch (e) 0); // parse(2)=20 → +1 = 21
|
|
|
|
print("liveness total: {}\n", total); // 50+70+30+40-1+21 = 210
|
|
return total;
|
|
}
|