85 lines
2.0 KiB
Plaintext
85 lines
2.0 KiB
Plaintext
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#define unify
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///unify(a, b)
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/**
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* unify :: TypeConLink -> TypeConLink -> ()
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*
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* Unifies types `a` and `b`.
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*
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* @param a the first type con
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* @param b the second type con
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*/
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var a = argument0;
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var b = argument1;
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assertInstanceof(a, TypeConLink);
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assertInstanceof(b, TypeConLink);
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if (instanceof(a, TypeCon1Link) && instanceof(b, TypeCon1Link))
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unifyType(a, b);
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else if (instanceof(a, TypeCon1Link) && !instanceof(b, TypeCon1Link))
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unify(b, a);
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else if (!instanceof(a, TypeCon1Link) && instanceof(b, TypeCon1Link)) {
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while (!ds_set_empty(b.from))
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replaceLink(ds_set_first(b.from), b, a);
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delete(b.type);
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delete(b);
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exit;
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}
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else if (!instanceof(a, TypeCon1Link) && !instanceof(b, TypeCon1Link)) {
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for (var i = 0; i < ds_list_size(a.to); i++)
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unify(a.to[|i], b.to[|i]);
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}
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#define unifyType
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///unifyType(a, b)
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/**
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* unifyType :: TypeConLink -> TypeConLink -> ()
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*
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* Unifies types `a` and `b`.
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*
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* @param a the first type con
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* @param b the second type con
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*/
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var a = argument0;
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var b = argument1;
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assertInstanceof(a, TypeCon1Link);
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assertInstanceof(b, TypeCon1Link);
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assertInstanceof(a.type, Type);
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assertInstanceof(b.type, Type);
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if (a == b)
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exit;
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//unify free types by taking the union of their traits and destroying the second type
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if (instanceof(a.type, FreeType) && instanceof(b.type, FreeType)) {
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ds_set_add_all(a.type.traits, b.type.traits);
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for (var trait = ds_set_first(b.type.traits); ds_set_exists(b.type.traits, trait); trait = ds_set_next(b.type.traits, trait))
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ds_set_add(a.type.traits, trait);
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while (!ds_set_empty(b.from))
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replaceLink(ds_set_first(b.from), b, a);
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delete(b.type);
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delete(b);
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exit;
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}
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//unify free type with concrete type by replacing all occurrences with the concrete type
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if (instanceof(a.type, FreeType) && !instanceof(b.type, FreeType)) {
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unify(b, a);
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exit;
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}
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if (!instanceof(a.type, FreeType) && instanceof(b.type, FreeType)) {
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while (!ds_set_empty(b.from))
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replaceLink(ds_set_first(b.from), b, a);
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delete(b.type);
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delete(b);
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exit;
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}
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