> I wouldn't consider the final one valid (even though it was accepted).

It was accepted as package name, but as a module it would hit a wall, ° since :: are translated to path delimiter /

    
  DB<83> use a::::b
Can't locate a//b.pm in @INC

[download]

I'm not sure if there are any file-systems with semantics for an unnamed directory between two '/', win at least gives me a hard time trying to create a directory with an empty string as name.

But I'm wondering if this might have some relevance as vulnerability, since I remember seeing sequences of // as special syntax for network resources.

update

°) It's possible on win at least, because it translates multiple / to no-ops, hence a//b is the same like a/b

so I created 

C:\tmp\x\y>echo warn 'inside';1 >z.pm

[download]

started the debugger and ran

  DB<5> use lib '.'

  DB<6> use x::::y::::z
inside at x//y///z.pm line 1.

[download]

It also reveals a trick to force a recompile of a module by adding more :: to the path.

Like that Perl won't find it cached in %INC and try to require it again.

  DB<7> use x::::y::::z

  DB<8> use x::::y::::::z
inside at x//y///z.pm line 1.
 at x//y///z.pm line 1.

[download]

DISCLAIMER: Too lazy to test this with linux (shame on me) and the rest of perlport... (no amiga handy...)

Cheers Rolf
(addicted to the Perl Programming Language :)
Wikisyntax for the Monastery

In reply to Re^2: Is there an official regex for checking module names? (updated) by LanX
in thread Is there an official regex for checking module names? by kcott

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