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https://github.com/Mercury-Language/mercury.git
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1d107c82ad
Estimated hours taken: 3 Add predicates to perform lower-bound and upper-bound searching, in which if a search for a key fails, we return the next lower (or higher) key and its associated value. library/bintree.m: library/rbtree.m: library/tree234.m: library/map.m: Add lower-bound and upper-bound search and lookup predicates. Add plain lookup predicates where missing, or move them next to their corresponding search preds. Make the handling of lookup errors more uniform. library/require.m: Move map__lookup_error here as report_lookup_error, for use by bintree, rbtree and tree234, as well as map.
143 lines
3.7 KiB
Mathematica
143 lines
3.7 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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:- pred error(string).
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:- mode error(in) is erroneous.
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% error(Message).
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% Abort with error 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 abort with 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.
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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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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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/* error/1, from require.m */
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:- pragma c_header_code("
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#include <stdio.h>
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#include ""mercury_trace_base.h""
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#include ""mercury_stack_trace.h""
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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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error_internal(Message).
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:- pred error_internal(string::in) is erroneous.
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% We define error using handwritten code in error_internal because we
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% need complete control over it if we want to call MR_dump_stack. In
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% particular we don't want to have to explicitly tell MR_dump_stack whether
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% a stack frame was generated by its caller. The easiest way to do
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% this is to make sure it wasn't.
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:- external(error_internal/1).
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:- pragma c_code("
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Define_extern_entry(mercury__require__error_internal_1_0);
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BEGIN_MODULE(require_internal_module)
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init_entry(mercury__require__error_internal_1_0);
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BEGIN_CODE
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/* code for predicate 'error_internal'/1 in mode 0 */
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Define_entry(mercury__require__error_internal_1_0);
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{
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String Message;
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Message = (String) r1;
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fflush(stdout);
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fprintf(stderr, ""Software error: %s\\n"", Message);
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MR_trace_report(stderr);
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MR_dump_stack(MR_succip, MR_sp, MR_curfr, FALSE);
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exit(1);
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}
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END_MODULE
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/*
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** Ensure that the initialization function for the above module gets run.
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*/
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/*
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INIT sys_init_require_internal_module
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*/
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extern ModuleFunc require_internal_module;
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void sys_init_require_internal_module(void);
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void sys_init_require_internal_module(void) {
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require_internal_module();
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}
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").
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:- end_module require.
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%-----------------------------------------------------------------------------%
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