Re: Language features affect style

A contrived example showing that private methods can be simulated with lexical coderefs:

use strict;
use warnings;

package Foo;

sub new { bless {salary => 100} }

my $private_method = sub {
    my $self   = shift;
    my $factor = shift || 2;
    $self->{salary} *= $factor;
};

sub get_salary {
    my $self = shift;
    $self->$private_method(10);
    return $self->{salary};
}

package main;

my $foo = Foo->new;
printf "salary is %s\n", $foo->get_salary;
[download]

Admittedly the boilerplate issue is still there.

Comment on Re: Language features affect style Download Code

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Re^2: Language features affect style by TimToady (Parson) on Jun 08, 2009 at 15:17 UTC
Indeed, which is why we've gotten rid of most of Perl 5's (not so) beloved boilerplate in Perl 6. Here's the same code (more or less) in Perl 6: `class Foo { has $!salary; method !private_method ($factor = 2) { $!salary *= $factor } method salary { self!private_method(10); $!salary } } my Foo $foo .= new(:salary(100)); say "salary is ", $foo.salary;` [download] This may or may not tweak the refactoring knob back toward methods; Perl 6 is still not Java, after all.	[reply] [d/l]
Re^3: Language features affect style by John M. Dlugosz (Monsignor) on Jun 09, 2009 at 19:13 UTC
`method salary { self!private_method(10); $!salary }` [download] Doesn't $!salary have to be called with an object? `self!salary`. Or has this been changed to figure that out for itself (implies self or $_ ?) now? I found it: For a call on your own private method, you may also use the attribute-ish form: `$!think($pinky) # short for $(self!think($pinky))` [download] I'm guessing you put this in after you got STD in fine enough shape and knew that could actually be made to work? With analogous meaning for the other sigils (that's not stated in S12)? —John	[reply] [d/l] [select]
Re^4: Language features affect style by TimToady (Parson) on Jun 09, 2009 at 23:15 UTC
Huh? `$!salary` is simply the name of the private storage area for the attribute. No calling involved, since the method already knows its own self, and whole point of `$!salary` is to tell the method it can access the storage directly rather than through a virtual method. The extra information is only necessary when calling something private in another object.	[reply] [d/l] [select]
Re^5: Language features affect style by John M. Dlugosz (Monsignor) on Jun 10, 2009 at 17:01 UTC
Re^6: Language features affect style by TimToady (Parson) on Jun 10, 2009 at 19:20 UTC
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Re^3: Language features affect style by Anonymous Monk on Jun 08, 2009 at 15:30 UTC
Perl 6 is still not Java, after all. Is it gasoline? No, perl is Camelia :)	[reply]
Re^4: Language features affect style by holli (Abbot) on Jun 10, 2009 at 06:51 UTC
Camelia? holli When you're up to your ass in alligators, it's difficult to remember that your original purpose was to drain the swamp.	[reply] [d/l]


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