Re: Dynamic Variant Record Creation

[Robert A Duff <bobduff@shell01.TheWorld.com>]

Warren <ve3wwg@gmail.com> writes:

> except that the discriminant also be described somehow
> as 3-bits.

I'm not sure what you mean.  If you're saying "I don't know
how to specify the layout for discriminants", then the answer
is "same as other components" -- you just put the usual
"Discrim at ... range 0..2" or whatever.  If you're saying
"It won't fit in 3 bits because it has more than 2**3 values,
then you're out of luck.

>> You said you wanted efficiency.  Well, this:
>> 
>>             T : Token_Type := Token_Type'Val(Character'Pos(Ch));
>> 
>> is unlikely to be efficient.  The case statement will be better
>> in that regard.
>
> If true, I'd like to know why. I can't see that in the compiled
> code being much other than a move short.  If I get time tonight,
> I'll investigate it.

Ah, I see I misread your code.  I thought you were using
'Image and 'Value.  Sorry.

So you're right -- the above 'Pos and 'Val should be efficient.
But I don't think it does what you want!  The 'Pos of the
Character '!' is not the same as the 'Pos of the Token '!'.

- Bob