==================
Simple procedure
==================

#procedure simplify(expr)
  id x = 1;
#endprocedure

---

(source_file
  (procedure_definition
    name: (identifier)
    (identifier)
    (substitution_statement
      (identifier)
      (number))))

==================
Procedure call
==================

#call simplify(result)

---

(source_file
  (call_statement
    name: (identifier)
    (identifier)))
