Re: Why put type information into syntax?

"Allister Cross" <across@vega.co.uk> writes:


> Does anyone know of any reasons why built-in type names should be
> incorporated in the syntax of a language. I have been looking at the
> Java yacc grammar produced by Dmitri Bronnikov. This grammar contains
> a 'PrimitiveType' production containing the built-in types of
> 'BOOLEAN', 'CHAR' and so on. What is the advantage off treating
> built-in types differently from user-defined types?? Would it not be
> better to treat all types uniformly, by not putting primitive types in
> the grammar, and resolving such typing issues during semantic
> analysis.




Well, in Java, the "primitive" types really are different from regular
class or interface types. For example:


                1. There is probably some automatic coersion between primitive
                      types.


                2. Primitive types compile to different bytecodes.


                3. Primitive values are assigned and passed by value instead
                      of by reference.




Okay, that's enough to show that many kinds of analysis (whether by a
tool or by a human) are going to be interested in primitive types
vs. other kinds of types. Furthermore, it's easy to specify this in
the grammar, so why not?


Lex

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