Distribution · system

QueryOS

Partial

Identify the host operating system and split its version string into parts, so a program can branch on platform without parsing $*DISTRO by hand.

Version: 0.1.2 zef:tbrowder
Depends: none beyond the core
License: Artistic-2.0
Its own test suite: 2 files, green
Checked: 2026-09-15 against Raku++ 3.28.0 and Rakudo 2026.08
Where it lives: raku.land · source

Install it #

$ rakupp install QueryOS

zef install QueryOS writes the same store; either installer leaves the module usable by both engines.

What it is for #

$*DISTRO tells you a name and a version string and leaves the interpretation to you — and the interpretation differs per platform, because macOS versions look nothing like Debian codenames.

This distribution wraps that into an object with three predicates and a set of version parts, so a platform branch reads as a question rather than a string comparison.

Asking about the host #

Anything this prints is specific to the machine it runs on, so the example asserts shape:

File

use QueryOS;

my $os = OS.new;

say 'class                : ', $os.^name;
say 'name is a Str        : ', $os.name ~~ Str;
say 'version is defined   : ', $os.version.defined;
say 'vnum is Numeric      : ', $os.vnum ~~ Numeric;
say '';
say 'exactly one predicate is true : ',
    ([+] $os.is-linux, $os.is-macos, $os.is-windows) == 1;
say 'all three return Bool         : ',
    ($os.is-linux ~~ Bool) && ($os.is-macos ~~ Bool) && ($os.is-windows ~~ Bool);

Output

class                : QueryOS::OS
name is a Str        : True
version is defined   : True
vnum is Numeric      : True

exactly one predicate is true : True
all three return Bool         : True

Constructing an OS on macOS prints WARNING: OS macos is not supported. Please file an issue. to stderr — unconditionally, once per construction. It is not visible above because the gate compares stdout, and it will pollute the output of any tool that builds one in a loop.

Splitting a version string #

File

use QueryOS;

for '10.15.7', '22.6', '1.0.1.buster', 'bookworm', '' -> $v {
    my %p = os-version-parts($v);
    say sprintf('%-14s => %s', $v.raku,
        %p.keys.sort.map({ "$_={%p{$_}.raku}" }).join(' '));
}

Output

"10.15.7"      => version-name="" version-serial="10.15.7" vnum=10.157e0 vshort-name=""
"22.6"         => version-name="" version-serial="22.6" vnum=22.6e0 vshort-name=""
"1.0.1.buster" => version-name="buster" version-serial="1.0.1" vnum=1.01e0 vshort-name="buster"
"bookworm"     => version-name="bookworm" version-serial=0 vnum=0e0 vshort-name="bookworm"
""             => version-name="" version-serial=0 vnum=0e0 vshort-name=""

os-version-parts is exported and works on any string, so you can use it without constructing an OS at all. Note version-serial is a Str for numeric-looking versions and the Int 0 for named ones, so its type is not stable.

The one thing to know #

vnum is a Num built by deleting the dots after the first, so ordering by it is wrong.

File

use QueryOS;

for '10.2', '10.9', '10.15', '10.15.7', '11.0' -> $v {
    say sprintf('  %-9s vnum = %s', $v, os-version-parts($v)<vnum>);
}
say '';
my @vers = <10.2 10.9 10.15 10.15.7 11.0>;
say 'sorted by vnum  : ', @vers.sort({ os-version-parts($_)<vnum> }).join(' ');
say 'true chronology : 10.2 10.9 10.15 10.15.7 11.0';

Output

  10.2      vnum = 10.2
  10.9      vnum = 10.9
  10.15     vnum = 10.15
  10.15.7   vnum = 10.157
  11.0      vnum = 11

sorted by vnum  : 10.15 10.15.7 10.2 10.9 11.0
true chronology : 10.2 10.9 10.15 10.15.7 11.0

10.15 becomes 10.15, 10.2 becomes 10.2, and numerically 10.2 is greater — so a version gate written as if $os.vnum >= 10.15 treats macOS 10.2 from 2002 as newer than 10.15 from 2019. Sorting five real version strings by vnum produces an order that is neither ascending nor descending in any meaningful sense.

The Num also loses precision by construction: 10.15.7 collapses to 10.157.

Compare version-serial component by component instead, or use Raku's own Version type, which knows how to order these.

Where the two engines differ #

Nowhere. Every shape assertion, every version split and the whole broken ordering were identical on Raku++ and Rakudo, including the stderr warning on macOS.

One thing to know before you reach for the rest of the interface: run-cli is exported and shells out. It is not a pure query, despite sitting in the same export list as os-version-parts.