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Help with basic OO question

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Former Member

‎2005 Mar 31 2:26 PM

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456

Right!

I know that '->' is for calling a method from a class.

I also know that '=>' is used calling a static method (whatever that is?).

But what on earth is '?=' used for???

Anyone got any ideas...

Thanking you kindly

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RichHeilman
Developer Advocate
Developer Advocate

‎2005 Mar 31 2:31 PM

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434

?= is use for casting. Narrowing and widening.

You will usually see this inside of a catch/endcatch.

    catch system-exceptions move_cast_error = 1.
      r_checking ?= r_account.
    call method r_account->show_balance.
    endcatch.

Check out this post.

Regards,

Rich Heilman

Right!

I know that '->' is for calling a method from a class.

I also know that '=>' is used calling a static method (whatever that is?).

But what on earth is '?=' used for???

Anyone got any ideas...

Thanking you kindly

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RichHeilman
Developer Advocate
Developer Advocate

‎2005 Mar 31 2:31 PM

0 Likes
435

?= is use for casting. Narrowing and widening.

You will usually see this inside of a catch/endcatch.

    catch system-exceptions move_cast_error = 1.
      r_checking ?= r_account.
    call method r_account->show_balance.
    endcatch.

Check out this post.

Regards,

Rich Heilman

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Former Member

‎2005 Mar 31 2:59 PM

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434

oh right that's it, casting...

That something to do with what is inherited from superclasses...

Thansk for the memory jog!