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11affd7576
compiler/prog_io_goal.m:
A NU-Prolog style if-then-else has three keywords. Look for situations
in which one or two are missing, and generate specific error messages
for them.
tests/invalid/malformed_ite.{m,err_exp}:
Test case for the new error messages.
tests/invalid/Mmakefile:
Enable the new test case.
72 lines
1.4 KiB
Mathematica
72 lines
1.4 KiB
Mathematica
%---------------------------------------------------------------------------%
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% vim: ts=4 sw=4 et ft=mercury
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%---------------------------------------------------------------------------%
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%
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% Check that we generate readable error messages for if-then-elses
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% that *attempt* to use "if C then T else E" syntax, but fail, because
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% they use the corresponding element of the "C -> T ; E" syntax.
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%
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% In the case of "if", the corresponding element is nothing.
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% In the case of "then", the corresponding element is "->".
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% In the case of "else", the corresponding element is ";".
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%
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% We test that the parser can generate a meaningful error message
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% in cases where one or two of the three keywords is wrong.
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:- module malformed_ite.
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:- interface.
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:- pred p(int::in, int::out) is det.
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:- implementation.
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:- import_module int.
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p(A, B) :-
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% Missing "if".
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( A < 10 then
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B = A
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else
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B = A + 1
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).
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p(A, B) :-
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% Wrong "then".
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( if A < 10 ->
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B = A
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else
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B = A + 1
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).
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p(A, B) :-
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% Wrong "else".
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( if A < 10 then
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B = A
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;
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B = A + 1
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).
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p(A, B) :-
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% Missing "if" and wrong "then".
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( A < 10 ->
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B = A
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else
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B = A + 1
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).
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p(A, B) :-
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% Missing "if" and wrong "else".
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( A < 10 then
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B = A
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;
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B = A + 1
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).
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p(A, B) :-
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% Wrong "then" and "else".
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( if A < 10 ->
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B = A
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;
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B = A + 1
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).
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