ConstOptree(3pm)

🌸 ConstOptree — the manual page, but make it cute 🌸

Ok so bestie, this is the docs for B::ConstOptree (it's in the ConstOptree(3pm) manual, if you're keeping score 💅). Sit down, hydrate, we're learning about optree constant folding for $^O, $^V, and $].

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✨ NAME ✨

B::ConstOptree — optree constant folding for $^O, $^V, and $] 🦋

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💖 SYNOPSIS 💖

Like, here's the whole vibe in one shot:

$ perl -MO=ConstOptree -MO=Deparse} -e \
       'require ($^O eq "MSWin32" ? "Win32.pm" : "POSIX.pm")'
require 'POSIX.pm';
-e syntax OK

See how it just knew? The $^O comparison got folded, so the deparse shows the survivor: require 'POSIX.pm'; ✨ And then -e syntax OK because obviously, it ate. 👑

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🎀 DESCRIPTION 🎀

So here's the tea, bestie: this module propagates constant folding for the variables $^O, $^V, and $]. 🌈

How? It installs custom PL_check handlers for the numeric and string comparison opcodes. Like, it's getting all up in the compiler's business (respectfully 🫶).

Inside those handlers, any reference to a $^O, $^V, or $] argument gets swapped out for a constant term. Specifically:

• $^O → a constant like "linux"
• $^V → a constant like v5.16.1
• $] → a constant like 5.016001

That's it. That's the whole thing. No cap. 💀

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⚠️ CAVEATS ⚠️

Ok now the part where we keep it real. 🙈

Regexp matching is not subject to constant folding. So expressions like $^O =~ /win32/i will not be reduced. Sorry babe, it's giving "not my department." 😭

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👑 AUTHOR 👑

Written by Alexey Tourbin <at@altlinux.org>. 🎀

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💜 COPYING 💜

Copyright (c) 2012 Alexey Tourbin

This is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version.

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And that's the whole page, bestie 💖 Manifesting a folder that folds your constants before you even blink. 🌟

This was perl v5.42.3, dated 2026-08-19, brought to you by the ConstOptree(3pm) manual. Byeee 🦋💅✨