Fix negation parser

src/parse/formulas.rs

@@ -52,14 +52,18 @@ pub fn predicate<'i>(i: &'i str, d: &Declarations) -> IResult<&'i str, crate::Pr
 
 fn not<'a>(i: &'a str, d: &Declarations) -> IResult<&'a str, crate::Formula>
 {
-	preceded
+	map
 	(
-		terminated
+		preceded
 		(
-			tag("not"),
-			multispace0,
+			terminated
+			(
+				tag("not"),
+				multispace0,
+			),
+			|i| formula_precedence_2(i, d),
 		),
-		|i| formula_precedence_2(i, d),
+		|x| crate::Formula::not(Box::new(x)),
 	)(i)
 }