Vera tip: emulating class-level enumerals

Newsletter · Original Contribution Joined: Dec 08, 2003 Posts: 1107

(Originally from Issue 1.1, Item 4.0)

From: Janick Bergeron

In Vera, enumerals cannot be overloaded as in VHDL. This means that
if I use "RESET" in my enumerated type, you can't! Furthermode,
Vera predefines a bunch of them in the file
which cannot be used either (and they are popular ones that *I*
would like to use, e.g. "ALL", "ANY", etc...).

C++ as the concept of class-level enumerated type. e.g.:

class myClass {
enum {Symbol1, Symbol2, Symbol3};
}

As long as these enumerated types are in different classes, the
symbols used for the enumerals can be overloaded. Each symbols is
accessed using the syntax classname::enumaral (e.g.: myClass::Symbol2).

You can emulate the same thing using public static data members in Vera.
For example:

class myClass {
static integer ANY := 0;
static integer ALL := 1;

task myTask(integer arg = 0 /* ANY */);
}

Notice how I'm now able to use these symbols since they are in a different
scope than enumerals. Unfortunately, they can be accidentally changed
(there is no concept of a "constant" in Vera) and must be referenced
trough an object instance. That is why I cannot use "ANY" as the default
input value for the "arg" argument in myClass::myTask. Once I have
an instance, I can use the following:

myClass obj = new;

obj.myTask(obj.ANY);

Added to my wish-list for Vera:
- Class-level enumerals
- "const" objects
- class-level reference to static data members (e.g. classname::member)

Janick Bergeron
Qualis Design Corp.