add support for embedded calls (syntax)

src/main.rs

@@ -638,6 +638,15 @@ mod tests {
         assert_eq!(submit(&mut wam, "?- call(david_lynch, X)."), true);
         assert_eq!(submit(&mut wam, "?- call(david_lynch, kyle(Film))."), true);
         assert_eq!(submit(&mut wam, "?- call(david_lynch, kyle(Film), _)."), false);
+
+        submit(&mut wam, "call_mult(P, X) :- call(call(P), X).");
+        
+        assert_eq!(submit(&mut wam, "?- call_mult(p(X), Y)."), true);
+        assert_eq!(submit(&mut wam, "?- call_mult(p(X), X)."), true);
+        assert_eq!(submit(&mut wam, "?- call_mult(p(one), X)."), true);
+        assert_eq!(submit(&mut wam, "?- call_mult(p(X), one)."), true);
+        assert_eq!(submit(&mut wam, "?- call_mult(p(two), one)."), false);
+        assert_eq!(submit(&mut wam, "?- call_mult(p(two), two)."), true);
     }
 }
 

src/prolog/prolog_parser.lalrpop

@@ -20,6 +20,25 @@ BoxedTerm : Box<Term> = {
 };
 
 Call : QueryTerm = {
+    "call" "(" <c:Call> <ts: ("," <BoxedTerm>)*> ")" => {
+        match c {
+            QueryTerm::CallN(mut terms) => {
+                let vt = terms.pop().unwrap();
+                let mut ts = ts;
+                
+                terms.append(&mut ts);
+                terms.push(vt);
+                
+                QueryTerm::CallN(terms)
+            },
+            QueryTerm::Term(Term::Clause(cell, atom, mut terms)) => {
+                let mut ts = ts;                
+                terms.append(&mut ts);
+                QueryTerm::Term(Term::Clause(cell, atom, terms))
+            },
+            _ => c
+        }
+    },    
     "call" "(" <a:Atom> "(" <ts: (<BoxedTerm> ",")*> <t:BoxedTerm> ")"
     <tss: ("," <BoxedTerm>)*> ")" => {
         let mut ts  = ts;