=======
no-body
=======

predicate foo();

mod::Type foo(int arg, Foo arg);

---

(ql 
  (moduleMember (classlessPredicate (returnType (predicate)) (predicateName) (empty))) 
  (moduleMember (classlessPredicate (returnType (typeExpr (moduleExpr (simpleId)) (className))) (predicateName) 
    (varDecl (typeExpr (typeLiteral)) (varName (simpleId))) (varDecl (typeExpr (className)) (varName (simpleId))) (empty))))

================
simple predicate
================

predicate foo(F f){
  f = f
}

int predicateWithResult(){
  result = 43
}

---

 (ql 
    (moduleMember (classlessPredicate (returnType (predicate)) (predicateName) (varDecl (typeExpr (className)) (varName (simpleId))) (body 
      (comp_term (variable (varName (simpleId))) (compop (eq)) (variable (varName (simpleId))))))) 
    (moduleMember (classlessPredicate (returnType (typeExpr (typeLiteral))) (predicateName) (body 
      (comp_term (variable (result)) (compop (eq)) (literal (integer)))))))

=====================
higher-order relation
=====================

int foo(X x, Y y) = name(pred1/1, pred2/3)(x.x(), result)

---

(ql (moduleMember 
  (classlessPredicate 
    (returnType (typeExpr (typeLiteral))) 
    (predicateName) 
    (varDecl (typeExpr (className)) (varName (simpleId))) 
    (varDecl (typeExpr (className)) (varName (simpleId))) 
    (higherOrderTerm (eq) (literalId) 
      (predicateExpr (aritylessPredicateExpr (literalId)) (slash) (integer)) 
      (predicateExpr (aritylessPredicateExpr (literalId)) (slash) (integer)) 
      (qualified_expr (variable (varName (simpleId))) (qualifiedRhs (predicateName))) 
      (variable (result)))))) 

===============
predicate alias
===============

predicate foo = somePredicate/12;

---

(ql (moduleMember (classlessPredicate 
  (returnType (predicate)) 
  (predicateName) (predicateAliasBody (eq) (predicateExpr (aritylessPredicateExpr (literalId)) (slash) (integer))))))