Re: [Patch, Fortran] SELECT TYPE with associate-name

[Daniel Kraft <d at domob dot eu>]

Janus Weil wrote:
> Btw: This associate-name feature of SELECT TYPE is practically
> identical to the ASSOCIATE statement, which means that the latter
> could be implemented with pretty much the same technique (plus some
> parsing bits). So, if people think that this is still ok as an
> early-stage-3 project, I could also implement ASSOCIATE (if not, I
> will start fixing some of the OOP PRs).

I thought about ASSOCIATE a little before I decided to implement BLOCK, 
and my opinion is that ASSOCIATE is probably a little more complicated, 
unfortunatly.  If I understand it correctly, you also can give variables 
an associate-name and use it later to set the variable, rather than just 
reading some value.

So in this case I think you either need to add a copying-back at the end 
or do the association with pointers.  I think we should also care about 
performance when associate-naming large arrays, so that this ideally 
goes without temporaries where possible.

My thoughts were to introduce a local variable just as you did for 
associating names to values (like function results or other 
calculations) but when the target is a EXPR_VARIABLE, copy the 
expression and substitute it directly at compile time for the 
associate-name; but I did not think really thoroughly about it, just 
enough to decide that BLOCK was probably easier (and I think BLOCK a 
little more useful).

Regarding whether to do this now or wait for next stage 1, I think we 
should in general wait as this is not really a bugfix; on the other 
hand, for me it would also be ok to do it quickly now, if others are 
also of this opinion.

BTW, as I did BLOCK, I would also volunteer to work on ASSOCIATE (next 
stage 1) if you want to work on other stuff then and bugfixing now.

Yours,
Daniel

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