perl syntax question

[whn]

Hi,

I inherited some perl codes from my ex-coworker.

One line of codes is like this:

return [COLOR=red]wantarray[/color] ? ($rc, $res) : $res;

What is the bare word 'wantarray'? Shouldn't be something like '$wantarray'? And I can not find anywhere the bareword 'wantarray' gets assigned a value.

This code is very old and has been used for many years. No one has ever asked, nor can they explain it to me. Is it safe to say this is simply a typo?

Thank you for you help.

 

[KevinADC]

wantarray is a perl function.

http://perldoc.perl.org/functions/wantarray.html

It allows your program to call the same function in list or scalar context.

------------------------------------------
- Kevin, perl coder unexceptional!

 

[stevexff]

wantarray returns true if the caller has invoked your code in a list context, and false if it's called in a scalar context.

In this example, he returns an array containing a return code and a value in a list context, and otherwise just the scalar value $res.

Does this help?

Steve

[small]"Every program can be reduced by one instruction, and every program has at least one bug. Therefore, any program can be reduced to one instruction which doesn't work." (Object:erlDesignPatterns)[/small]

 

[whn]

Thank you, Kevin!!

 

[ishnid]

Larry Wall himself acknowledges that it's badly named and should probably have been called "wantlist".

 

[ChrisHunt]

The perldoc page Kevin linked to is the first hit from

http://www.google.com/search?q=wantarray

- not always friutful, but a sensible first step when you find a command you're unfamiliar with.

-- Chris Hunt
Webmaster & Tragedian
Extra Connections Ltd