[nem-en] Re: += Macro and delegates

[Andrey Khropov]

Kamil Skalski wrote:

> Ok, I guess you would like to use existing transformation function you
> are writing, which performs
> TExpr -> CodeDomExpression

That's right. But first I want to make sure that it's a delegate attachment and
not an integer addition. I could have done this easily if e and method were
TExpr (just by inspecting their Type property) but with PExpr it's harder
without type information.

> 
> We need to create following codedom structure:
> 
> CodeAttachEventStatement (
>       CodeEventReferenceExpression  (
>           CodeExpression targetObject,
>   	   string eventName
>       )
>       CodeExpression listener
> )
Of course.

> 
> So assuming we have
> TExpr.DefValIn (LocalVal ("_N_cached"), TExpr  (this.button1) as t1,
>   TExpr.Call (TExpr.MethodRef (TExpr  (_N_cached), IMethod (add_Click)  as
> m1),       [  TExpr (System.EventHandler(this.button1_Click)) as listener ] )

Well, but I guess this is just a sketch. And the problem is that it depends on
a particular way "+=" is implemented today. One day optimizer may eliminate
unnecessary caching and this pattern won't work anymore.

> 
> I would do:
> 
> CodeAttachEventStatement (
>       CodeEventReferenceExpression  (
>           texpr_to_codeexpr (t1),
>   	   m1.Name.Substring (4)
>       ),
>       texpr_to_codeexpr (listener)
> )

Something like that but this will require a sort of pattern matching on
'expanded' like you wrote above.

 
> If you prefer to operate on PExpr,

I don't but I have to if I deal with 'original'

> then you should fetch method's name
> just like before, but
> use  pexpr_to_codeexpr  on respectively  $e and $method

Well I use texpr_to_codeexpr everywhere. Making pexpr_to_codeexpr will more
than double almost the same code (And I don't need it anywhere else yet).

What I'm looking for is an easy way to perform PExpr -> TExpr conversion for
these relatively easy expressions for e and method given some context.


P.S. I see discussing such a subject in forum isn't interactive enough. Do you
mind if I contact you by Jabber/IRC/ICQ ?

-- 
AKhropov