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Branches: main, 11.07 Allow mutable variables to be initialised by impure functions. Also fix bug #223. Make thread.semaphore.init/1 and thread.mvar.init/1 impure, as they should be. They were introduced to be used as mutable initialisers, which led to the oversight of making them pure. compiler/make_hlds_passes.m: compiler/prog_mutable.m: Modify the generated mutable initialisation predicates such that the initial value may be the return value of a impure function call. compiler/purity.m: Ignore warnings about unnecessary impure annotations on goals in generated mutable predicates. These would now appear when a mutable is initialised by a call to a pure function, or by a constant. doc/reference_manual.texi: NEWS: Document the language change. library/thread.mvar.m: library/thread.semaphore.m: Make thread.semaphore.init/1 and thread.mvar.init/1 impure. tests/hard_coded/Mmakefile: tests/hard_coded/mutable_init_impure.exp: tests/hard_coded/mutable_init_impure.m: Add test case.
47 lines
1.0 KiB
Mathematica
47 lines
1.0 KiB
Mathematica
% Test initialisation of mutables by impure functions.
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:- module mutable_init_impure.
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:- interface.
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:- import_module io.
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:- pred main(io::di, io::uo) is det.
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%-----------------------------------------------------------------------------%
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:- implementation.
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:- import_module thread.
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:- import_module thread.semaphore.
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:- mutable(sem1, semaphore, init_sem, ground, [untrailed, attach_to_io_state]).
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:- mutable(sem2, semaphore, init_sem, ground, [untrailed, constant]).
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:- impure func init_sem = semaphore.
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init_sem = Sem :-
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impure Sem = semaphore.init(1).
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:- mutable(foo, string, init_foo, ground, [untrailed, constant]).
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:- semipure func init_foo = string.
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init_foo = X :-
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promise_semipure X = "Testing...".
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main(!IO) :-
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get_sem1(Sem1, !IO),
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semaphore.wait(Sem1, !IO),
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get_sem2(Sem2),
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semaphore.wait(Sem2, !IO),
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get_foo(Foo),
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io.write_string(Foo, !IO),
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io.nl(!IO),
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io.write_string("Success.\n", !IO).
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%-----------------------------------------------------------------------------%
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% vim: ft=mercury ts=4 sts=4 sw=4 et
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