Re: Question about enumeration types

["Marc A. Criley" <mcqada@earthlink.net>]

Reinert Korsnes wrote:
> 
> Hi,
> 
> (sorry for somehow repeating a question)
> 
> Given the program as below.  Here I did put "E : E1" inside
> a record since "E" is also a possible value for the enumeration type E1.
> 
> This is somehow verbose.  Is it a more elegant way ?
> 
> I find it boring that extending the range of possible values of
> an enumeration type may easily cause conflicts with variable names,
> and new variable names may cause conflicts values for enumeration
> types.  I sometimes would like to have the reserved word "Exit"
> as a possible value of an enumeration type....  Am I thinking
> somewhat wrong ?

Well, if you add a variable name, a type name, a procedure name, etc.,
you also have to worry about about causing conflicts with existing
variable, type, procedure, etc., names that have the same visibility, so
there's nothing particularly different about adding enumeration
literals.

One technique I've seen used is to prefix each enumeration literal with
its type name or some other convention.  For your example:

   type E1 is (E1_A, E1_B, E1_C, E1_D, E1_E);

Now you can add E1_Exit with no problem.

Marc A. Criley
Senior Staff Engineer
Quadrus Corporation
www.quadruscorp.com