"3.202_007_29"

Eval treats the string as a literal number.

One can use _ as delimiter in long literal numbers but not when numifying strings

Yes- that's pretty much the point I was making.
However, I wasn't sure if the need to eval comes about solely by introducing an underscore, so I chose to specify the strings that don't require eval rather than the strings that do.
I had wondered whether eval might also cater for version strings that contain multiple decimal points (v-strings), but a quick check suggests that's not the case. (Someone please let me know if I've got that wrong.)

Cheers,
Rob

> I had wondered whether eval might also cater for version strings that contain multiple decimal points (v-strings),

The last part of dagolden's summary recommends to avoid dotted-integer versions

Given these criteria, my recommendation is to use decimal version numbers, put them in quotes, and add a string eval:

our $VERSION = "0.001"; $VERSION = eval $VERSION;

This is safe and effective and always works. By putting any $VERSION in quotes, even if it isn’t an alpha, you don’t have to remember to add them if you ever change to an alpha version. (And numbers with trailing zeroes are nicely formatted when parsed for distribution versions.)

If you really want to have a dotted-integer module version, then I strongly recommend that you limit your module to Perl 5.10 (or require version.pm and at least Perl 5.8.1) and that you never use an alpha version number. Always quote your dotted integer version when you define it and always use a leading-v to guide your users towards proper usage.

It’s unfortunate that version numbers are so complicated in Perl, but if you follow the recommendations in this article, your version numbers will be as boring as possible. And if you’ve read this all the way to the end, I hope I’ve convinced you that ‘boring’ version numbers are exactly what you want.

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

I read dagolden's article thrice and my head keeps smoking because of the confusion.
• I was wondering if this confusion could be fixed with a new keyword version which accepts all formats and converts them.

  Then I realized that numerous tools statically parse .pl/.pm files for $VERSION

• My next idea was to introduce magic var $VERSION acting like version (kind of tied scalar) and being automatically part of the package (hence no our required)

  Not sure if that's feasable.

• My last idea was to look for advice in defining standards ...

  (... head has finished smoking, brain is ready to serve now!)

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

++ on both posts, except why would one group the fractional digits as "3.202_007_29" rather than as "3.2020_07_29", which seems much more intuitive to me?

---

Give a man a fish:  <%-{-{-{-<

I followed the 3 digit convention, but since _ is primarily used to distinguish dev releases, it might be inappropriate using more than one here.

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