The dreaded with...

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The dreaded with...
Debugging today, I found another gotcha.

In this case, both Self and DisconnectedClient has a property named ClientIdentifier.

Note the difference for the mouse-over and the evaluation.
https://drive.google.com/file/d/0B1MyXorVzay9SjNraEdqV1hLSTg/edit?usp=sharing

Comments

  1. Bill MeyerAugust 7, 2014 at 7:32 AM

    Nice! ;)

    ReplyDelete
  2. Jeroen Wiert PluimersAugust 7, 2014 at 8:06 AM

    The love for `with`...

    ReplyDelete
  3. mezenAugust 7, 2014 at 8:47 AM

    This is one reason why my company (and I^^) dont allow the usage of with ;-)
    With (ahaha^^) great power comes great responsibility

    ReplyDelete
  4. Asbjørn HeidAugust 7, 2014 at 1:51 PM

    Had they at least gone the route VB did, and require a . to access the "with'ed" members...

    ReplyDelete
  5. Nándor KissAugust 8, 2014 at 12:04 AM

    with is evil... :)

    ReplyDelete
  6. Bill MeyerAugust 8, 2014 at 4:27 AM

    With can be used responsibly, as in:
    with AnObj do
      Prop1 := MyVal;
      Prop2 := SomeValue;
      Prop3 := SomeOtherValue;
    end;

    Where usage becomes evil is when the with clause contains more than a few lines of simple code, or when it specifies multiple objects. In the latter case, it is as difficult and dangerous as multiple inheritance.

    Given that it is always an alternative to declare a local variable of the desired type, with a short name, and thereby gain the benefits of with, while encountering none of its ugly aspects, that is generally preferable.

    ReplyDelete
  7. Lars FosdalAugust 8, 2014 at 4:34 AM

    with
      r as SomeVar[ix].Reference,
      x as SomeOtherRef
    do begin
      r.prop := x.Value;
     ...

    would have been nice.

    ReplyDelete
  8. Jeroen Wiert PluimersAugust 8, 2014 at 4:42 AM

    Lars Fosdal yes, I've seen that being suggested numerous times (;

    ReplyDelete
  9. Asbjørn HeidAugust 8, 2014 at 4:50 AM

    Lars Fosdal Certainly an improvement, but personally I'd prefer inline variable declaration and references (ala C++).

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  10. Bill MeyerAugust 8, 2014 at 5:44 AM

    Asbjørn Heid Well, C++ is certainly available, if you prefer it. ;)

    ReplyDelete
  11. Lars FosdalAugust 8, 2014 at 5:50 AM

    Asbjørn Heid - The type is implied in my suggestion - and you could cast the right side if you needed to.  Another point is that this limits the scope to just the with clause.

    ReplyDelete
  12. Asbjørn HeidAugust 8, 2014 at 9:47 AM

    Bill Meyer True true.

    ReplyDelete

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