3c4305f78f
A comptime value param whose constraint is a plain enum ($o: Ord) now binds its enum-literal argument to the variant tag during inlined comptime-call lowering. The tag is recorded in comptime_value_bindings (readable downstream via comptimeIntNamed / direct map lookup, and as an array-dim style const-int leaf) AND the param is bound into scope as an enum_init value so body comparisons like 'if o == .a' lower as ordinary enum comparisons. Distinct ordering args monomorphize the inlined body per value. A non-constant argument or an unknown variant emits a loud diagnostic and binds nothing — never a silent default. Locked by examples/0627-comptime-enum-value-param.sx.
28 lines
978 B
Plaintext
28 lines
978 B
Plaintext
// Comptime ENUM value parameter: `$o: <EnumType>` binds the enum-literal
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// argument to its variant tag, monomorphizes the inlined body per distinct
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// ordering value, and resolves `o` in the body as a compile-time-known enum
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// constant — usable both in `if o == .a` comparisons AND as a comptime-readable
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// variant tag during lowering (a downstream lowerer reads it via
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// `comptime_value_bindings`, exercised here as the `[o]i64` array dimension).
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#import "modules/std.sx";
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Ord :: enum { a; b; c; }
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pick :: ($o: Ord) -> i64 {
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if o == .a { return 10; }
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if o == .b { return 20; }
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return 30;
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}
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// `o` read as a compile-time integer (its variant tag) in a TYPE position.
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tag_dim :: ($o: Ord) -> i64 {
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arr : [o]i64 = ---;
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return arr.len;
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}
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main :: () {
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print("{}\n", pick(.b)); // 20
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print("{} {} {}\n", pick(.a), pick(.b), pick(.c)); // 10 20 30
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print("{} {} {}\n", tag_dim(.a), tag_dim(.b), tag_dim(.c)); // 0 1 2
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}
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