e395a08331
Parser now accepts a `..` spread in a parameterized-type arg list; in instantiateGenericStruct a spread arg bound to the variadic type-param expands via packTypeElems (so `..sources.T` projects each source pack element protocol type-arg into ..$Ts). `Combined(s64, ..sources.T)` for a VL(s64) source instantiates Combined(s64, s64). examples/209 (with explicit per-element xx erase). 244 examples + unit green. Next: (..sources) whole-pack materialization with per-element erasure into the protocol-typed field (c.sources = (..sources) currently segfaults).
28 lines
950 B
Plaintext
28 lines
950 B
Plaintext
// Phase 6 — pack-spread in a parameterized-type's arg list:
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// `Combined($R, ..sources.T)`. Inside a pack-fn, `..sources.T` projects each
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// source's protocol type-arg and spreads them into the generic struct's pack
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// type-param `..$Ts`, so `Combined(s64, ..sources.T)` for a single `VL(s64)`
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// source instantiates `Combined(s64, s64)` (field `sources: (VL(s64))`).
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#import "modules/std.sx";
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VL :: protocol(T: Type) { get :: () -> T; }
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IntCell :: struct { v: s64; }
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impl VL(s64) for IntCell { get :: (self: *IntCell) -> s64 => self.v; }
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Combined :: struct($R: Type, ..$Ts: []Type) {
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sources: (..VL(Ts));
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value: $R;
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}
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make :: (..sources: VL) -> s64 {
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c : Combined(s64, ..sources.T) = ---; // instantiate with the spread type-arg
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c.sources.0 = xx sources[0]; // erase the concrete source to VL(s64)
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return c.sources.0.get();
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}
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main :: () -> s32 {
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print("{}\n", make(IntCell.{ v = 7 })); // 7
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0;
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}
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