Why does Net::Curl::Easy->new work but Net::Curl::Easy::new does NOT?

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

(Note: I am aware that the standard way is to use Some::Class->new, but a static function (should?) work

First I do require, as use allows them both to work for some reason (why?):

require Net::Curl; Then, the following (assume I have use strict) fails with Bareword "Net::Curl::Easy::new" not allowed while "strict subs" in use

my $c = Net::Curl::Easy::new;
[download]

while the following does not

my $c = Net::Curl::Easy->new;
[download]

Also weird is that if I enter

require Net::Curl;
my $c = Net::Curl::Easy::new;
[download]

in Reply it works (as two commands). But if I entered the commands on the same line: require Net::Curl;my $c = Net::Curl::Easy::new; it fails (why?).

In addition, I'm not quite understanding the difference(s) between all these (note the command clearly isn't a reference, but just for the sake of argument). Which ones are the same, which ones are different (in general), which ones are the same in this case?:

&Net::Curl::Easy::new;
&Net::Curl::Easy::new();
Net::Curl::Easy::new();
Net::Curl::Easy::new;
&{Net::Curl::Easy::new}; #equivalent to Net::Curl::Easy::new->&*,right
+?
Net::Curl::Easy::new->();
[download]

EDIT Not using the strict pragma gives the error: 'easy' is not a Net::Curl::Easy object at the line assigning $c. I thought parentheses aren't necessary here (perldoc/perlsub):

The & is optional in modern Perl, as are parentheses if the subroutine has been predeclared.

Comment on Why does Net::Curl::Easy->new work but Net::Curl::Easy::new does NOT? Select or Download Code

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Re: Why does Net::Curl::Easy->new work but Net::Curl::Easy::new does NOT? by LanX (Saint) on May 07, 2018 at 19:30 UTC
A method is a sub which expects as first argument the object (ref) or the class name (string) Arrow does this implicitly for you, otherwise you need to do it explicitly. See perlobj#A-Method-is-Simply-a-Subroutine Cheers Rolf _{(addicted to the Perl Programming Language and ☆☆☆☆ :) Wikisyntax for the Monastery}	[reply]
Re: Why does Net::Curl::Easy->new work but Net::Curl::Easy::new does NOT? by shmem (Chancellor) on May 07, 2018 at 23:39 UTC
`require Net::Curl;` Then, the following (assume I have `use strict`) fails with `Bareword "Net::Curl::Easy::new" not allowed while "strict subs" in use +<?c> <c> my $c = Net::Curl::Easy::new;` [download] while the following does not `my $c = Net::Curl::Easy->new;` [download] That's because require is a runtime directive, and strict is compile time. During the parse of the script it is not distinguishable whether `Net::Curl::Easy::new` is a subroutine call or a bareword. Add parens to disambiguate: `my $c = Net::Curl::Easy::new();` [download] or wrap the require statement into a BEGIN block: `BEGIN { require Net::Curl::Easy }` [download] which loads, compiles and executes `Net/Curl/Easy.pm` during the parse, and thus makes known `Net::Curl::Easy::new` as being a subroutine in perl's symbol table. But then, if `Net::Curl::Easy::new` is not insentitive to be called as a class method or a function, (i.e. it takes arguments and doesn't validate them proper), you may have to pass the classname, as LanX noted: `my $c = Net::Curl::Easy::new( q(Net::Curl::Easy) );` [download] - or not. Documentation or source code should reveal that. perl -le'print map{pack c,($-++?1:13)+ord}split//,ESEL'	[reply] [d/l] [select]