Re: [sv-bc] Where can $typeof() be used? Issues 224 and 277)

>This is not much worse than
>constant system functions that can be used in a constant
>expression (which an implementation also couldn't allow pli
>to override)

For these, I would say that PLI can override them, but the PLI versions
are not allowed in constant expressions.  Only the built-in versions are
allowed in constant expressions.  So if you override them, you get an
error, just as you would for any PLI function in a constant expression.
This is not the same as saying that the names are reserved and cannot
be overridden.

This is also an extension of an existing semantic rule.  System functions
are generally allowed as operands in expressions.  There are extra semantic
restrictions on constant expressions.  These used to disallow any system
functions.  Now they allow certain constant system functions.

With $typeof, the proposal would allow a system function call in places
where system function calls have never been syntactically legal, but only
for this one system function.  So this would be a lot worse.

Steven Sharp
sharp@cadence.com