[Bioperl-l] For CVS developers - potential pitfallwith "returnundef"

[Lincoln Stein]

If the documentation says "returns false" then I expect to be able to do this:

	@result = foo();
	die "foo() failed" unless @result;

If the documentation says "returns undef" then I expect this:

	@result = foo();
	die "foo() failed" unless $result[0];

Lincoln


On Wednesday 31 May 2006 14:08, Hilmar Lapp wrote:
> On May 31, 2006, at 12:03 PM, Lincoln Stein wrote:
> > If the subroutine is documented to return "false" on failure, then
> > one must call
> > return (or "return ()" ).
>
> The problem seems to be that 'a value that evaluates to either true
> or false' and 'a [meaningful] value or undef' and 'a value or
> false' ('a value or no value) are not the same in perl. And what
> would/should one expect if the doc states 'true on success and false
> otherwise'?
>
> Maybe the documentation should also be fixed to avoid any ambiguity.
> I.e., avoid documenting 'a value or false' because it may be
> ambiguous (not only) to the less proficient. 'True or false' should
> imply a value being returned.
>
> Comments?
>
> 	-hilmar

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Lincoln D. Stein
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