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ENHANCED: Throw representation errors for DCG bodies that use unsupported constructs.

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This addresses #2285.
This commit is contained in:
Markus Triska
2024-01-20 10:33:24 +01:00
parent 98a046500f
commit 0559ddca2a
1 changed files with 6 additions and 2 deletions
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8
src/lib/dcgs.pl
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@@ -176,8 +176,10 @@ dcg_constr(phrase(_)). % 7.14.9
dcg_constr(phrase(_,_)). % extension of 7.14.9
dcg_constr(phrase(_,_,_)). % extension of 7.14.9
dcg_constr(!). % 7.14.10
%% dcg_constr(\+ _). % 7.14.11 - not (existence implementation dep.)
%% dcg_constr((_->_)). % 7.14.12 - if-then (existence implementation dep.)
dcg_constr(\+ _) :- % 7.14.11 - not (existence implementation dep.)
throw(error(representation_error(dcg_body), phrase/3)).
dcg_constr((_->_)) :- % 7.14.12 - if-then (existence implementation dep.)
throw(error(representation_error(dcg_body), phrase/3)).
% The principal functor of the first argument indicates
% the construct to be expanded.
@@ -244,6 +246,8 @@ seqq([Es|Ess]) --> seq(Es), seqq(Ess).
error_goal(error(E, must_be/2), error(E, must_be/2)).
error_goal(error(E, (=..)/2), error(E, (=..)/2)).
error_goal(error(representation_error(dcg_body), Context),
error(representation_error(dcg_body), Context)).
error_goal(E, _) :- throw(E).
user:goal_expansion(phrase(GRBody, S, S0), GRBody2) :-