mirror of
https://github.com/carbon-language/carbon-lang.git
synced 2026-10-02 06:05:46 +01:00
Geoff Romer
853360345e
* Make parentheses optional for alternatives with no arguments. * Use `,` instead of `;` as separator for alternatives, and make the trailing separator optional.
44 lines
910 B
Plaintext
44 lines
910 B
Plaintext
********** source program **********
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choice Ints {
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alt None ();
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alt One Int;
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alt Two (0 = Int, 1 = Int);
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}
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fn main () -> Int {
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var auto: x = Ints.None();
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var auto: y = Ints.One(0 = 42);
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var auto: n = 0;
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match (y) {
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case Ints.None =>
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n = (n + 2);
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case Ints.One(0 = auto: x) =>
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n = ((x + 1) - 42);
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case Ints.Two(0 = auto: a, 1 = auto: b) =>
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n = 2;
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}
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match (x) {
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case Ints.One(0 = auto: x) =>
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n = (x + 2);
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case Ints.None() =>
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n = (n - 1);
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case Ints.Two(0 = auto: x, 1 = auto: y) =>
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n = 5;
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}
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return n;
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}
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********** type checking **********
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--- step exp () --->
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--- step exp Int --->
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--- step exp (0 = Int, 1 = Int) --->
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--- step exp Int --->
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--- handle value Int with (0 = Int, 1 = Int)<1>(Int,) --->
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--- step exp Int --->
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--- handle value Int with (0 = Int, 1 = Int)<2>(Int,Int,) --->
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--- step exp Int --->
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--- step exp Int --->
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--- step exp auto --->
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13: type error in call
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expected: Int
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actual: Tuple(0 = Int)
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