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01a0b8278f
Estimated hours taken: 15 Branches: main, release Implement superclass reduction in the style of CHRs rather than as a top down search. This is shorter, simpler, and more consistent with the rest of the typeclass implementation. It also removes a few XXXs and fixes a bug reported by Julien. compiler/hlds_data.m: Add an ancestors field to the hlds_constraint type. This caches all the ancestors of assumed constraints, along with proofs (in the form of a sequence of subclass constraints) of how each ancestor is derived. Update this field whenever new assumed constraints are created, by traversing the class hierarchy bottom up. Delete the old subclass_details type, which was part of the superclass table. compiler/typeclasses.m: Use the cached ancestors to apply the class rules, rather than performing a top down search. compiler/type_util.m: Apply substitutions to the ancestors. compiler/typecheck.m: compiler/typecheck_info.m: Update to account for the additional field. compiler/*.m: Remove the superclass table from the module_info and from the interface to context reduction; it is no longer needed. compiler/hlds_out.m: Don't output the superclass table. tests/valid/Mmakefile: tests/valid/superclass_bug.m: Regression test for the bug that is now fixed.
39 lines
897 B
Mathematica
39 lines
897 B
Mathematica
:- module superclass_bug.
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:- interface.
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:- type s ---> s.
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:- type e ---> e.
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:- type c ---> c.
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:- typeclass my_stream(Stream, State) <= (Stream -> State) where
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[
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pred name(Stream::in, string::out, State::di, State::uo) is det
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].
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:- typeclass my_god(Stream, State, Error)
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<= ( my_stream(Stream, State), (Stream -> Error) ) where [].
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:- typeclass my_input(Stream, Unit, State, Error)
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<= my_god(Stream, State, Error) where [].
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:- type tab_expander(S).
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:- instance my_stream(tab_expander(S), s)
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<= my_input(S, c, s, e).
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:- implementation.
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:- type tab_expander(S)
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---> tab_expander(int, S).
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:- instance my_stream(tab_expander(S), s)
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<= my_input(S, c, s, e) where
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[
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pred(name/4) is foo
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].
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:- pred foo(tab_expander(S)::in, string::out, s::di, s::uo) is det
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<= my_input(S, c, s, e).
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foo(tab_expander(_, Stream), Name, !S) :-
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name(Stream, Name, !S).
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