[Jastadd] [Q] unknown type ?

From: Na, Hyunik <hina_at_kaist.ac.kr>
Date: Wed, 21 Dec 2011 18:36:14 +0900

Hello JastAddJ developers,

In Java1.4Frontend/TypeCheck.jrag, the following line exists:

        syn TypeDecl AssignExpr.sourceType() =
getSource().type().isPrimitive() ? getSource().type() : unknownType();

which means the source type of an assign expression is the unknown type
unless it is a primitive type.
Why should it be?

and the AssignSimpleExpr.typeCheck() is written as follows:

  public void AssignSimpleExpr.typeCheck() {
      error("left hand side is not a variable");
    else if(!sourceType().assignConversionTo(getDest().type(), getSource())
&& !sourceType().isUnknown())
      error("can not assign " + getDest() + " of type " +
getDest().type().typeName() +
            " a value of type " + sourceType().typeName());

This means that, if the source type is unknown, it is not an error even when
the source type is not assign-compatible
with the destination type for a simple assignment.
It is hard for me to figure out what's going on here.

Why do you introduce the unknown type during the type checking process?

- Hyunik
Received on Wed Dec 21 2011 - 10:37:06 CET

This archive was generated by hypermail 2.3.0 : Wed Apr 16 2014 - 17:19:06 CEST