28 lines
1.1 KiB
Plaintext
28 lines
1.1 KiB
Plaintext
// Option 3 — `xx <lvalue>` borrows the operand's storage instead of
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// heap-copying. The protocol value's `ctx` points directly at the local;
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// mutations through the protocol are visible to the original.
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//
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// The witness is TrackingAllocator: incrementing the parent allocator's
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// counter happens through the Allocator protocol value. If `xx tracker`
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// heap-copied the Tracker, the parent counter would land in the copy
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// and the local would stay at zero. With Option 3 the local sees the
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// increments because they ARE the local.
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#import "modules/std.sx";
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#import "modules/std/mem.sx";
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main :: () -> s32 {
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gpa := GPA.init();
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tracker := TrackingAllocator.init(xx gpa); // value, stack-local
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// xx tracker — operand is an identifier (lvalue), so the protocol
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// borrows tracker's storage. No heap copy. Mutations propagate.
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push Context.{ allocator = xx tracker, data = null } {
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p := context.allocator.alloc_bytes(128);
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context.allocator.dealloc_bytes(p);
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}
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print("alloc_count = {}\n", tracker.alloc_count);
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print("dealloc_count = {}\n", tracker.dealloc_count);
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return 0;
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}
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