Re: Perl allows package names consisting entirely of colons

in reply to Perl allows package names consisting entirely of colons

Seems to work only when the colons come in pairs:

#! perl
use strict;
use warnings;

package :::::
{
    sub x
    {
        printf "(%s)\n", __PACKAGE__;
    }
}

package main;

:::::::x();
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Produces:

23:01 >perl 405_Obfu.pl
Bareword "::::::" refers to nonexistent package at 405_Obfu.pl line 27
+.
Invalid version format (non-numeric data) at 405_Obfu.pl line 17, near
+ "package ::::"
syntax error at 405_Obfu.pl line 17, near "package :::::"
Execution of 405_Obfu.pl aborted due to compilation errors.

23:02 >
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“Curiouser and curiouser!” cried Alice.

Update: ~~D’oh! (slaps forehead). Of course! :: is a synonym for main, and so is ::main and therefore ::::, likewise ::::::, etc., etc. (See Packages.)~~ This “insight” is wrong — see reply by tobyink, below.

Athanasius <°(((>< contra mundum

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Re^2: Perl allows package names consisting entirely of colons by tobyink (Canon) on Nov 27, 2012 at 13:33 UTC
In terms of the `package` keyword itself, `::` and `main` are distinct packages, and `::::` is another package entirely... `$ perl -Mstrict -Mwarnings -E'package main; say __PACKAGE__' main $ perl -Mstrict -Mwarnings -E'package ::main; say __PACKAGE__' main $ perl -Mstrict -Mwarnings -E'package ::; say __PACKAGE__' :: $ perl -Mstrict -Mwarnings -E'package ::::; say __PACKAGE__' ::::` [download] `{ package main; sub xxx { 0 }; package ::; sub xxx { 1 }; package ::::; sub xxx { 2 }; } use 5.010; say ::xxx(); # 0 say ::::xxx(); # 1 say ::::::xxx(); # 2` [download] `perl -E'sub Monkey::do{say$_,for@_,do{($monkey=[caller(0)]->[3])=~s{::}{ }and$monkey}}"Monkey say"->Monkey::do'`	[reply] [d/l] [select]

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Re^2: Perl allows package names consisting entirely of colons
by tobyink (Canon) on Nov 27, 2012 at 13:33 UTC

In terms of the package keyword itself, :: and main are distinct packages, and :::: is another package entirely...

$ perl -Mstrict -Mwarnings -E'package main; say __PACKAGE__'
main
$ perl -Mstrict -Mwarnings -E'package ::main; say __PACKAGE__'
main
$ perl -Mstrict -Mwarnings -E'package ::; say __PACKAGE__'
::
$ perl -Mstrict -Mwarnings -E'package ::::; say __PACKAGE__'
::::
[download]

{
    package main;
    sub xxx { 0 };
    package ::;
    sub xxx { 1 };
    package ::::;
    sub xxx { 2 };
}

use 5.010;
say ::xxx();      # 0
say ::::xxx();    # 1
say ::::::xxx();  # 2
[download]

perl -E'sub Monkey::do{say$_,for@_,do{($monkey=[caller(0)]->[3])=~s{::}{ }and$monkey}}"Monkey say"->Monkey::do'

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