/** @see jaskell.compiler.JaskellVisitor#visit(ConstructorPattern) */
public Object visit(ConstructorPattern a) {
String cname = a.getConstructor().getName();
/* retrieve parameter types of constructor */
ConstructorDefinition ctor = (ConstructorDefinition) a.getConstructor().lookup(cname);
if (ctor == null) throw new TypeError("Undefined constructor pattern " + a);
/* type of data constructed by constructor */
TypeInstantiator ti = new TypeInstantiator(ctor.getDataType());
Type rtype = ti.instance();
Map map = ti.getMap();
TypeSubstitution ts = new TypeSubstitution(map);
Iterator ittypes = ctor.getParameters().iterator();
/* retrieve type of patterns */
Iterator it = a.getSubPatterns();
while (it.hasNext()) {
try {
Pattern p = (Pattern) it.next();
Type actual = TypeFactory.freshBinding();
Type formal = ts.substitute((Type) ittypes.next());
/* unify both types */
p.setType(tu.unify(formal, actual, typeVariablesMap));
} catch (NoSuchElementException nex) {
throw new TypeError("Wrong number of arguments to pattern " + a);
}
}
a.setType(rtype);
return a.getType();
}
/** @see jaskell.compiler.JaskellVisitor#visit(Constructor) */
public Object visit(Constructor a) {
Type ret = a.getType();
if (ret != null) return ret;
String vname = a.getName();
ConstructorDefinition def = (ConstructorDefinition) a.lookup(vname);
if (def == null) // unknown symbol
throw new CompilerException("Unknown constructor " + vname);
ret = new TypeInstantiator(def.getType()).instance();
a.setType(ret);
return ret;
}
/** @see jaskell.compiler.JaskellVisitor#visit(ConstructorDefinition) */
public Object visit(ConstructorDefinition a) {
/* returns a FunctionType */
return a.getType();
}