e3ca724bfa
Support destructuring in match arms:
- Tuple: (a, b) binds subject._0 / _1
- Struct: Point { x: px, y: py } and shorthand Point { x, y }
Bootstrap: matchPatternBindings for pkTuple/pkStruct; register local
tuple typedefs from function bodies. Selfhost: parse, Sema_BindPattern,
Lcx_PatternBindings with scope defines. Fix operator-overload path that
crashed when typeName was null after pattern binds.
Example: examples/struct_tuple_pat.bux. Selfhost-loop IDENTICAL.
54 lines
1.0 KiB
Plaintext
54 lines
1.0 KiB
Plaintext
// Struct and tuple patterns in match: (a, b), Point { x, y }
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import Std::Io::{PrintLine, PrintInt};
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import Std::Test::{Test_AssertEqInt, Test_Pass};
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struct Point {
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x: int,
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y: int,
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}
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func SumPair(t: (int, int)) -> int {
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match t {
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(a, b) => a + b,
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_ => 0
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}
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}
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func PointCode(p: Point) -> int {
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match p {
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Point { x: px, y: py } => px * 10 + py,
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_ => -1
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}
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}
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func PointShorthand(p: Point) -> int {
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// { x, y } means { x: x, y: y }
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match p {
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Point { x, y } => x + y,
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_ => 0
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}
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}
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func Main() -> int {
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let t: (int, int) = (10, 20);
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Test_AssertEqInt(SumPair(t), 30);
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let lit: (int, int) = (7, 8);
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let s: int = match lit {
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(a, b) => a * b,
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_ => 0
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};
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Test_AssertEqInt(s, 56);
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let p: Point = Point { x: 3, y: 4 };
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Test_AssertEqInt(PointCode(p), 34);
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Test_AssertEqInt(PointShorthand(p), 7);
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PrintInt(SumPair(t));
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PrintLine("");
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PrintInt(PointCode(p));
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PrintLine("");
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Test_Pass("struct_tuple_pat");
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return 0;
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}
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