How is this sub returning an object instead of a CODEREF

windowbreaker has asked for the wisdom of the Perl Monks concerning the following question:

I am reading thru the code in the Web::Scraper module, and don't understand how the imported subroutine named scraper is returning a Web::Scraper object.

In Web/Scraper.pm you have this

sub import {
    ...
    *{"$pkg\::scraper"} = _build_scraper($class);
}

sub _build_scraper {
    my $class = shift;
    return sub(&) {
        my($coderef) = @_;
        bless { code => $coderef }, $class;
    };
}
[download]

I get that scraper executes _build_scraper, which is a prototyped sub that takes a coderef as it's only argument. But it looks to me that calling scraper { } from the client code will return not a Web::Scraper object, but a CODEREF that, when executed, will return a Web::Scraper object using the sub{} block given to scraper{}.

If anyone can shed light on this to help me better understand what's happening that would be great.

Comment on How is this sub returning an object instead of a CODEREF Download Code

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Re: How is this sub returning an object instead of a CODEREF by Corion (Patriarch) on Jul 13, 2012 at 17:26 UTC
The difference is quite subtle: `{"$pkg\::scraper"} = _build_scraper($class);` [download] ... and what you thought you saw was (or at least, I thought I saw that, for a moment): `{"$pkg\::scraper"} = \&_build_scraper($class);` [download] This installs the result of `_build_scraper($class);` as the sub `scraper` in your code. And the result of `_build_scraper($class)` is what returns objects.	[reply] [d/l] [select]
Re^2: How is this sub returning an object instead of a CODEREF by windowbreaker (Sexton) on Jul 13, 2012 at 18:06 UTC
Good catch, I didn't see that. Thanks.	[reply]