boolean-expr: eliminate double negations

diff --git a/extra/boolean-expr/boolean-expr.factor b/extra/boolean-expr/boolean-expr.factor
index 46449d74868d9f86fd86d08b7062dd061db43b57..a0b54caddfe19db1c2a59793cf04a11588e820da 100644 (file)
--- a/extra/boolean-expr/boolean-expr.factor
+++ b/extra/boolean-expr/boolean-expr.factor
@@ -40,7 +40,7 @@ GENERIC: ¬ ( x -- expr )
 
 METHOD: ¬ { ⊤ } drop ⊥ ;
 METHOD: ¬ { ⊥ } drop ⊤ ;
-
+METHOD: ¬ { ¬ } x>> ;
 METHOD: ¬ { ⋀ } [ x>> ¬ ] [ y>> ¬ ] bi ⋁ ;
 METHOD: ¬ { ⋁ } [ x>> ¬ ] [ y>> ¬ ] bi ⋀ ;