[fpc-pascal] Operator overload resolution with arrays

Maciej Izak hnb.code at gmail.com
Mon Feb 5 21:02:27 CET 2018


2018-02-05 19:54 GMT+01:00 Sven Barth via fpc-pascal <
fpc-pascal at lists.freepascal.org>:

> Now I see why it is how it is.
>
> The maximum extent would be to accept overloads (and helpers) that are
> visible
> at the parameter type's declaration, because they would necessarily be
> visible
> in all specializations as well. That would be pretty much the same as how
> it
> currently accepts operators defined on the type, just one symtable up. It
> would
> also solve the "implementation restriction" from the manual - and only
> that. I
> think?
>
>
> That *could* be a possibility. I'd need to think about it a bit though to
> be sure that there are no caveats.
>

It may be good feature or more troubles ;) The only acceptable types where
"one symtable up" should be used, are types with own RTTI info:

type
  MyInteger = type Integer;
   { .. some operators for MyInteger  ... }
  TMyHelper = type helper for MyInteger
     { something }
  end;

type alias declaration for our case is not an option:

type
  MyInteger = Integer;
  { .. some operators for MyInteger  ... }
  TMyHelper = type helper for MyInteger
     { something }
  end;

for such case TMyHelper (or operator) should be invisible in
specializations, otherwise compiled program will explode :P.

-- 
Best regards,
Maciej Izak
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