public TypeInfo typeCheck(TypeEnv tenv) throws TypeException {
if (tenv.get(0, index) != null)
throw new TypeException("duplicate variable: " + name(), this);
varType = TypeInfo.get(type());
tenv.put(0, index, varType);
valueType = ((ASTreeTypeEx) initializer()).typeCheck(tenv);
valueType.assertSubtypeOf(varType, tenv, this);
return varType;
}
public TypeInfo typeCheckForAssign(TypeEnv tenv, TypeInfo valueType) throws TypeException {
type = tenv.get(nest, index);
if (type == null) {
type = valueType;
tenv.put(0, index, valueType);
return valueType;
} else {
valueType.assertSubtypeOf(type, tenv, this);
return type;
}
}
public TypeInfo typeCheck(TypeEnv tenv) throws TypeException {
TypeInfo[] params = ((ParamListEx2) parameters()).types();
TypeInfo retType = TypeInfo.get(type());
funcType = TypeInfo.function(retType, params);
TypeInfo oldType = tenv.put(0, index, funcType);
if (oldType != null) throw new TypeException("function redefinition: " + name(), this);
bodyEnv = new TypeEnv(size, tenv);
for (int i = 0; i < params.length; i++) bodyEnv.put(0, i, params[i]);
TypeInfo bodyType = ((ASTreeTypeEx) revise(body())).typeCheck(bodyEnv);
bodyType.assertSubtypeOf(retType, tenv, this);
return funcType;
}
public SubstMap unify(final Loc loc, final Type other, final TypeEnv env) {
if (env.checkVisited(this, other)) return SubstMap.EMPTY;
if (other instanceof TypeVar) return SubstMap.bindVar(loc, (TypeVar) other, this);
// if our application expression can be evaluated, unify against that.
if (isAbsApply()) return eval().unify(loc, other, env);
final Type otherEval = other.deref().eval();
if (otherEval instanceof TypeApp) {
final TypeApp otherApp = (TypeApp) otherEval;
final SubstMap baseSubst = base.unify(loc, otherApp.base, env);
if (baseSubst != null) {
final SubstMap argSubst =
arg.subst(baseSubst).unify(loc, otherApp.arg.subst(baseSubst), env);
if (argSubst != null) return baseSubst.compose(loc, argSubst);
}
} else if (kind.equals(otherEval.getKind())) {
// other is not an application expression, but kinds match.
// other type classes do opportunistic matching of type apps
// implementations of unify. This approach is really ad-hoc,
// needs to be rationalized.
return otherEval.unify(loc, this, env);
}
return null;
}
public TypeInfo typeCheck(TypeEnv tenv) throws TypeException {
type = tenv.get(nest, index);
if (type == null) throw new TypeException("undefined name: " + name(), this);
else return type;
}