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yap-6.3/pl/errors.yap

134 lines
3.4 KiB
Prolog

/*************************************************************************
* *
* YAP Prolog *
* *
* Yap Prolog was developed at NCCUP - Universidade do Porto *
* *
* Copyright L.Damas, V.S.Costa and Universidade do Porto 1985-1997 *
* *
**************************************************************************
* *
* File: errors.yap *
* comments: error messages for YAP *
* *
* *
* *
*************************************************************************/
/** @defgroup YAPErrorHandler Error Handling
@ingroup YAPErrors
@{
The error handler is called when there is an execution error or a
warning needs to be displayed. The handlers include a number of hooks
to allow user-control.
Errors are terms of the form:
- error( domain_error( Domain, Culprit )`
- error( evaluation_error( Expression, Culprit )`
- error( existence_error( Object, Culprit )`
- error( instantiation_error )`
- error( permission_error( Error, Permission, Culprit)`
- error( representation_error( Domain, Culprit )`
- error( resource_error( Resource, Culprit )`
- error( syntax_error( Error )`
- error( system_error( Domain, Culprit )`
- error( type_error( Type, Culprit )`
- error( uninstantiation_error( Culprit )`
*/
:- system_module( '$_errors', [system_error/2], ['$Error'/1,
'$do_error'/2,
system_error/3,
system_error/2]).
:- use_system_module( '$messages', [file_location/2,
generate_message/3,
translate_message/4]).
/**
* @pred system_error( +Error, +Cause)
*
* Generate a system error _Error_, informing the possible cause _Cause_.
*
*/
prolog:system_error(Type,Goal) :-
'$do_error'(Type,Goal).
'$do_error'(Type,Goal) :-
throw(error(Type, print_message(['while calling goal = ~w'-Goal,nl]))).
/**
* @pred system_error( +Error, +Cause, +Culprit)
*
* Generate a system error _Error_, informing the source goal _Cause_
*
*
* ~~~~~~~~~~
* ~~~~~~~~~~
*
*
*/
system_error(Type,Goal) :-
throw(error(Type, print_message(['while calling goal = ~w'-Goal,nl]))) .
'$do_pi_error'(type_error(callable,Name/0),Message) :- !,
'$do_error'(type_error(callable,Name),Message).
'$do_pi_error'(Error,Message) :- !,
'$do_error'(Error,Message).
'$Error'(E) :-
'$LoopError'(E, top).
%%
% error_handler(+Error,+ Level)
%
% process an error term.
%
error_handler(Error, Level) :-
'$LoopError'(Error, Level).
'$LoopError'(_, _) :-
flush_output(user_output),
flush_output(user_error),
fail.
'$LoopError'(Error, Level) :- !,
'$process_error'(Error, Level),
fail.
'$LoopError'(_, _) :-
flush_output,
'$close_error',
fail.
'$process_error'('$forward'(Msg), _) :-
!,
throw( '$forward'(Msg) ).
'$process_error'(error(event(abort,I),C), Level) :-
!,
(
current_prolog_flag(break_level, 0),
Level \== top
->
print_message(informational,abort(user)),
fail
;
throw( error(event(abort,I),C) )
).
'$process_error'(error(permission_error(module,redefined,A),B), Level) :-
Level \= top, !,
throw(error(permission_error(module,redefined,A),B)).
'$process_error'(Error, _Level) :-
functor(Error, Severity, _),
print_message(Severity, Error),
!,
'$close_error'.
'$process_error'(error(Type,Info), _, _) :-
print_message(error,error(unhandled_exception(Type),Info)).
%% @}