Re^2: Would someone mind helping me understand this Perl OO code?

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Re^3: Would someone mind helping me understand this Perl OO code? by almut (Canon) on Dec 22, 2009 at 16:04 UTC
`Node->new(...)` implicitly passes the package name (Node) as the first argument to the constructor... (so you have 4 args in the right slots, and everything is fine)	[reply] [d/l]
Re^4: Would someone mind helping me understand this Perl OO code? by romandas (Pilgrim) on Dec 22, 2009 at 16:11 UTC
I'm sure this behavior is documented somewhere, but didn't see it. Do you know where it can be found? Since new isn't a reserved word, how does perl know to pass the package name implicitly into that method in the first place? I could have just as ~~badly~~easily named the constructor 'bargle'. Is the package name passed implicitly on every method call? Or just the one where the object is blessed?	[reply]
Re^5: Would someone mind helping me understand this Perl OO code? by almut (Canon) on Dec 22, 2009 at 16:16 UTC
Do you know where it can be found? ...for example in perltoot (search for "Method Call" (case-sensitively)).	[reply]
Re^5: Would someone mind helping me understand this Perl OO code? by kennethk (Abbot) on Dec 22, 2009 at 16:18 UTC
In perlboot, an intro to OO in Perl, it is discussed in The extra parameter of method invocation. Update: To answer your updated question, the package name or blessed object are passed in a method invocation whenever you use the The Arrow Operator to invoke a package method. So `Node->new()` will pass "Node" and `new()`, `Node::new()` or `$code_ref->()` would not.	[reply] [d/l] [select]
Re^5: Would someone mind helping me understand this Perl OO code? by ikegami (Patriarch) on Dec 22, 2009 at 16:18 UTC
It's the first thing perlobj says about methods A Method is Simply a Subroutine Unlike say C++, Perl doesn't provide any special syntax for method definition. (It does provide a little syntax for method invocation though. More on that later.) A method expects its first argument to be the object (reference) or package (string) it is being invoked on.	[reply]
Re^3: Would someone mind helping me understand this Perl OO code? by ikegami (Patriarch) on Dec 22, 2009 at 16:10 UTC
Oops, ignore my earlier post. `Node->new($ip, $mac_address, $machine);` [download] is basically the same as `Node::new('Node', $ip, $mac_address, $machine);` [download] The main difference is that it checks the parent classes for `new` if sub `Node::new` doesn't exist.	[reply] [d/l] [select]


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