From: Markus Triska <triska@metalevel.at>
Date: Sat, 20 Jan 2024 09:24:57 +0000 (+0100)
Subject: MODIFIED: (->)/2 in DCGs is now only supported in the context of if-then-else.
X-Git-Tag: v0.9.4~25^2~4
X-Git-Url: https://git.sagredo.dev/?a=commitdiff_plain;h=98a046500f487fb9a1acc35df012f11ee364f1fa;p=scryer-prolog.git

MODIFIED: (->)/2 in DCGs is now only supported in the context of if-then-else.

That is, ( If -> Then ; Else ) is still supported, but ( If -> Then ) not.
---

diff --git a/src/lib/dcgs.pl b/src/lib/dcgs.pl
index 9f7dfacf..0876bd5a 100644
--- a/src/lib/dcgs.pl
+++ b/src/lib/dcgs.pl
@@ -177,7 +177,7 @@ 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((_->_)). % 7.14.12 - if-then (existence implementation dep.)
 
 % The principal functor of the first argument indicates
 % the construct to be expanded.