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35474ce0ce
Estimated hours taken: 8 Move exception handling into the standard library, and change error/1 so that it throws an exception. This has two advantages: one is that user code can now catch exceptions caused by calls to error/1, the other is that the debugger handles calls to error/1 more gracefully (by virtue of its existing support for exception handling). extras/exceptions/exception.m: library/exception.m: Move exception.m from `extras' into the standard library. Change the code for handling uncaught exceptions so that it prints out the same diagnostics that error/1 used to print out (i.e. a stack trace and the last debugger event number). extras/exceptions/Mmakefile: extras/exceptions/test_exceptions.exp: extras/exceptions/test_exceptions.m: extras/exceptions/test_exceptions_func.exp: extras/exceptions/test_exceptions_func.m: extras/exceptions/test_uncaught_exception.exp: extras/exceptions/test_uncaught_exception.m tests/hard_coded/exceptions/Mmakefile: tests/hard_coded/exceptions/test_exceptions.exp: tests/hard_coded/exceptions/test_exceptions.m: tests/hard_coded/exceptions/test_exceptions_func.exp: tests/hard_coded/exceptions/test_exceptions_func.m: tests/hard_coded/exceptions/test_uncaught_exception.exp: tests/hard_coded/exceptions/test_uncaught_exception.exp2: tests/hard_coded/exceptions/test_uncaught_exception.m Move the exception test cases from extras/exceptions to a new directory tests/hard_coded/exceptions. Also, change the expected output for the `test_uncaught_exception' test case, since it now prints out more information. tests/hard_coded/Mmakefile: Add `exceptions' to the list of subdirectories. extras/exceptions/README: Delete this file, since the files that it refers to have now all been moved elsewhere. library/require.m: Change error/1 so that it throws an exception. library/library.m: Add exceptions.m to the list of modules in the standard library.
95 lines
2.6 KiB
Mathematica
95 lines
2.6 KiB
Mathematica
%-----------------------------------------------------------------------------%
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% Copyright (C) 1993-1999 The University of Melbourne.
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% This file may only be copied under the terms of the GNU Library General
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% Public License - see the file COPYING.LIB in the Mercury distribution.
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%-----------------------------------------------------------------------------%
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:- module require.
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% Main author: fjh.
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% Stability: medium to high.
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% This module provides features similar to <assert.h> in C.
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%-----------------------------------------------------------------------------%
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:- interface.
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:- type software_error ---> software_error(string).
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:- pred error(string).
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:- mode error(in) is erroneous.
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% error(Message).
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% Throw a `software_error(Message)' exception.
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% This will normally cause execution to abort with an error
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% message.
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:- pred require(pred, string).
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:- mode require((pred) is semidet, in) is det.
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% require(Goal, Message).
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% Call goal, and call error(Message) if Goal fails.
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% This is not as useful as you might imagine, since it requires
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% that the goal not produce any output variables. In
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% most circumstances you should use an explicit if-then-else
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% with a call to error/1 in the "else".
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:- pred report_lookup_error(string, K, V).
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:- mode report_lookup_error(in, in, unused) is erroneous.
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% report_lookup_error(Message, Key, Value)
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% Call error/1 with an error message that is appropriate for
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% the failure of a lookup operation involving the specified
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% Key and Value. The error message will include Message
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% and information about Key and Value.
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%-----------------------------------------------------------------------------%
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:- implementation.
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:- import_module string, list, std_util, exception.
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require(Goal, Message) :-
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( call(Goal) ->
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true
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;
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error(Message),
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fail
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).
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%-----------------------------------------------------------------------------%
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report_lookup_error(Msg, K, V) :-
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KeyType = type_name(type_of(K)),
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ValueType = type_name(type_of(V)),
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functor(K, Functor, Arity),
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( Arity = 0 ->
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FunctorStr = Functor
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;
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string__int_to_string(Arity, ArityStr),
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string__append_list([Functor, "/", ArityStr], FunctorStr)
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),
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string__append_list(
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[Msg,
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"\n\tKey Type: ",
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KeyType,
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"\n\tKey Functor: ",
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FunctorStr,
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"\n\tValue Type: ",
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ValueType
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],
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ErrorString),
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error(ErrorString).
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%-----------------------------------------------------------------------------%
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% Hopefully error/1 won't be called often (!), so no point inlining it.
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:- pragma no_inline(error/1).
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error(Message) :-
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throw(software_error(Message)).
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:- end_module require.
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%-----------------------------------------------------------------------------%
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