Re: Why put type information into syntax?

Allister Cross wrote:
>> 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


Michael Spencer <michael.prqa@indigo.ie> wrote:
>I can think of two reasons, first, in C and C++ I know, built-in type
>names are keywords. By enforcing this rule in the grammar your parser
>becomes a lot cleaner. Also, conveniently, by treating them as
>keywords you can prevent parse conflicts.


Here is a similar peculiarity from Java:


            class A
            {
                    void f ()
                    {
                          long A = 42;
                          System.out.println ((A)-1); /*VAR*/
                          System.out.println ((long)-1); /*TYPE*/
                    }
            }


At /*VAR*/ "(A)" is an expression returning the value of the local
variable "A". Coincidentally "A" is also the name of the class being
defined.


At /*TYPE*/ "(long)" is a cast from integer to long.


I would be surprised if these two constructs could be handled in the
same way in the grammar without adding extra complexity to later
phases.


Tim

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