v-strings are used by the VERSION argument in a use or require. You cannot pass anything else!

that is not correct.

#!/usr/bin/perl
require 5.006_001;

package vstring;
our $VERSION = '1.0.1';

package number;
our $VERSION = 1.34_001e-5;

package string;
our $VERSION = '1.2beta4a';

package main;
print $vstring::VERSION, $/;
print $number::VERSION, $/;
print $string::VERSION, $/;

## prints:
## 1.01
## 1.34001e-005
## 1.2beta4a
[download]

don't use v-strings, there are alternatives.

~Particle *accelerates*

That's not what I'm talking about. See Everything you wanted to know about Module Version Numbers and Checking, specifically,

The thing between the module name and the list must be a v-string or numeric literal. Anything else is rejected by the parser, unlike the normal indirect-object syntax that can be overridden with braces even if it doesn't smell like an indirect object.

For example, you cannot write:

use VersionTest '1.2.3' qw/foo bar/; #string

my $needed= v2.3.4;
use VersionTest $needed qw/foo bar/; #not a literal
[download]

A variable named $package::VERSION is just another scalar and you can do anything with it.

For the require/use VERSION only (what you thought I meant?) to assert the perl version, it will take a float or a v-string to serve this purpose, and any other string including "1.2beta4a" as a module name instead. Using floats and the 3-digit convention, you are limited to the significance of the float (is that enough parts?).

Throwing v-strings into the mix doesn't cause any more problems than having numbers and strings (both) available. If you define module's $VERSION="1.0.2"; and use the old-style import method for asserting the version desired 1.0.4, it will use == in the comparison and ignore everything after the 1.0 in both cases, causing a false "accept".

here is a much better approach, IMHO, but that's not "built-in" to the semantics.

Funny thing is, using the indirect object syntax is a bit of a hack anyway, since that's not directly fed to the import method. Maybe I should forget that and encourage a revival of the "old" method, passing the desired version as an argument to the import list?

—John