built-in method

consistency_error/3

Description

consistency_error(Consistency, Argument1, Argument2)

Throws a consistency error. Used when two directives or predicate arguments are individually correct but together are not consistent. For example, a predicate and its alias having different arity in a uses/2 directive. This built-in method is declared private and thus cannot be used as a message to an object. Calling this predicate is equivalent to the following sequence of goals:

...,
context(Context),
throw(error(consistency_error(Consistency,Argument1,Argument2), Context)).

This allows the user to generate errors in the same format used by the runtime.

Possible values representing Consistency checks include:

  • same_arity

  • same_number_of_parameters

  • same_number_of_arguments

  • same_closure_specification

Modes and number of proofs

consistency_error(+atom, @nonvar, @nonvar) - error

Errors

When called:
consistency_error(Consistency, Argument1, Argument2)

Examples

% code that will trigger consistency errors when compiled:

% predicates (and non-terminals) aliases must have the same
% arity as the original predicates (and non-terminals)
:- uses(list, [
    member/2 as in/1
]).

% meta-predicate templates should be consistent with how closures
% are used regarding the number of additional arguments
:- public(p/2).
:- meta_predicate(p(1, *)).

p(G, A) :-
    call(G, A, 2).

See also

catch/3, throw/1, context/1, instantiation_error/0, uninstantiation_error/1, type_error/2, domain_error/2, existence_error/2, permission_error/3, representation_error/1, evaluation_error/1, resource_error/1, syntax_error/1, system_error/0