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Persist a Raku value to a file and read it back, using Raku source as the on-disk format.

Version

0.0.2 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 Storable::Lite

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

What it is for #

Saving a Raku data structure between runs usually means choosing a format and losing something to it: JSON has no Rat and no Set, YAML has no types at all, and a binary format needs a schema.

This distribution takes the shortest path. It writes $value.raku and reads it back with EVAL, so anything whose .raku round-trips survives exactly.

Saving and loading #

use Storable::Lite;

my $dir = $*TMPDIR.add("store-{$*PID}");
$dir.mkdir;
LEAVE { .unlink for $dir.dir; $dir.rmdir }
my $f = $dir.add('x.raku').absolute;

sub trip($label, $v) {
    to-file($f, $v);
    my $back = from-file($f);
    say sprintf('%-8s same type=%-5s eqv=%s',
        $label, $v.WHAT === $back.WHAT, $v eqv $back);
}

trip 'Int',   42;
trip 'Str',   'hi';
trip 'Rat',   1/3;
trip 'Array', [1, 'two', 3.5];
trip 'Hash',  { a => 1, b => 'x' };
trip 'Bool',  True;
trip 'Set',   set(<a b>);
trip 'Date',  Date.new('2024-03-01');

Int      same type=True  eqv=True
Str      same type=True  eqv=True
Rat      same type=True  eqv=True
Array    same type=True  eqv=True
Hash     same type=True  eqv=True
Bool     same type=True  eqv=True
Set      same type=True  eqv=True
Date     same type=True  eqv=True

A Rat stays a Rat, a Set stays a Set and a Date stays a Date — which no text format above manages without a schema.

What the file holds #

use Storable::Lite;

my $dir = $*TMPDIR.add("store2-{$*PID}");
$dir.mkdir;
LEAVE { .unlink for $dir.dir; $dir.rmdir }
my $f = $dir.add('conf.raku').absolute;

to-file($f, [ 'example.invalid', 8080, 3 ]);
say 'the file is Raku source:';
say '  ', $f.IO.slurp.trim;
say '';
say 'which is why it reads back with its types intact:';
say '  ', from-file($f).map(*.^name).join(' ');

the file is Raku source:
  $["example.invalid", 8080, 3]

which is why it reads back with its types intact:
  Str Int Int

Which is the appeal and the warning in one line.

The role #

use Storable::Lite;

class Config does FileStore {
    has Str $.host is rw;
    has Int $.port is rw;
}

my $dir = $*TMPDIR.add("store3-{$*PID}");
$dir.mkdir;
LEAVE { .unlink for $dir.dir; $dir.rmdir }
my $f = $dir.add('c.raku').absolute;

say 'the role adds instance methods : ',
    Config.^can('to-file') && Config.^can('from-file') ?? 'to-file and from-file' !! 'none';

the role adds instance methods : to-file and from-file

FileStore gives a class the same two operations as methods rather than subs.

The one thing to know #

from-file is EVAL. Reading a data file executes it.

The unit opens with use MONKEY-SEE-NO-EVAL and from-file slurps the file and evaluates its contents as Raku source. A file that contains BEGIN { run 'rm', '-rf', $some-path }; 99 will do exactly that and then return 99, and nothing in the interface distinguishes it from a file holding the number 99.

This is fine for a file your own program wrote in a directory your own program controls. It is not a data format. Do not point from-file at anything a user supplied, anything that arrived over a network, or anything in a world-writable directory — it is equivalent to raku that-file.

If you need to read untrusted structured data, use JSON.

Where the two engines differ #

Nowhere. Every type in this page round-tripped identically on Raku++ and Rakudo, and the on-disk format is the same text.

Two smaller returns to know about, the same on both. An empty file gives back an undefined value rather than an error, and a missing file gives back False — so neither failure throws, and both look like data.