[fpc-pascal] optional parameter

Flávio Etrusco flavio.etrusco at gmail.com
Mon May 3 19:28:13 CEST 2010

2010/5/3 spir ☣ <denis.spir at gmail.com>:
> Hello,
> A few questions on the topic:
> * Is it possible to define an optional parameter without default value?
> * Is it at all possible for an optional *argument* not to be the last in actual call? Eg
>     procedure p(a:Integer=0 ; b:Integer=0)
>  How can the caller pass b and not a?

No and no.

> * The ref states: "For dynamic arrays or other types that can be considered as equivalent to a pointer, the only possible default value is Nil."
> Does this apply to any non-atomic type? Which are the "other types that can be considered as equivalent to a pointer"?

Class, AnsiString.

> Tried with a record, but cannot make it be accepted by the compiler. Needed to change the
> parameter to be a pointer to the record instead (so the default can be nil), but this creates a
> trap for the calling code.
> Else, is there a common trick or workaround?

What trap?


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