Perl6::Slurp(3pm)

💖 Perl6::Slurp — the slurp built-in from Perl 6, but make it Perl 5 💖

okay so bestie, you know how in Perl 6 there's this gorgeous little built-in called slurp that just... reads a whole thing in one go, no ceremony, no local $/ = undef, no drama? Yeah. This module is that. In Perl 5. You're welcome. 🫶

---

✨ NAME ✨

Perl6::Slurp — it implements the Perl 6 slurp built-in, fr fr. 💅

---

🌸 SYNOPSIS 🌸

use Perl6::Slurp;

# Slurp a file by name...

$file_contents = slurp 'filename';
$file_contents = slurp '<filename';
$file_contents = slurp '<', 'filename';
$file_contents = slurp '+<', 'filename';

# Slurp a file via an (already open!) handle...

$file_contents = slurp \*STDIN;
$file_contents = slurp $filehandle;
$file_contents = slurp IO::File->new('filename');

# Slurp a string...

$str_contents = slurp \$string;
$str_contents = slurp '<', \$string;

# Slurp a pipe (not on Windows, alas)...

$str_contents = slurp 'tail -20 $filename |';
$str_contents = slurp '-|', 'tail', -20, $filename;

# Slurp with no source slurps from whatever $_ indicates...

for (@files) {
    $contents .= slurp;
}

# ...or from the entire ARGV list, if $_ is undefined...

$_ = undef;
$ARGV_contents = slurp;

# Specify I/O layers as part of mode...

$file_contents = slurp '<:raw', $file;
$file_contents = slurp '<:utf8', $file;
$file_contents = slurp '<:raw :utf8', $file;

# Specify I/O layers as separate options...

$file_contents = slurp $file, {raw=>1};
$file_contents = slurp $file, {utf8=>1};
$file_contents = slurp $file, {raw=>1}, {utf8=>1};
$file_contents = slurp $file, [raw=>1, utf8=>1];

# Specify input record separator...

$file_contents = slurp $file, {irs=>"\n\n"};
$file_contents = slurp '<', $file, {irs=>"\n\n"};
$file_contents = slurp {irs=>"\n\n"}, $file;

# Input record separator can be regex...

$file_contents = slurp $file, {irs=>qr/\n+/};
$file_contents = slurp '<', $file, {irs=>qr/\n+|\t{2,}};

# Specify autochomping...

$file_contents = slurp $file, {chomp=>1};
$file_contents = slurp {chomp=>1}, $file;
$file_contents = slurp $file, {chomp=>1, irs=>"\n\n"};
$file_contents = slurp $file, {chomp=>1, irs=>qr/\n+/};

# Specify autochomping that replaces irs
# with another string...

$file_contents = slurp $file, {irs=>"\n\n", chomp=>"\n"};
$file_contents = slurp $file, {chomp=>"\n\n"}, {irs=>qr/\n+/};

# Specify autochomping that replaces
# irs with a dynamically computed string...

my $n = 1;
$file_contents = slurp $file, {chomp=>sub{ "\n#line ".$n++."\n"};

# Slurp in a list context...

@lines = slurp 'filename';
@lines = slurp $filehandle;
@lines = slurp \$string;
@lines = slurp '<:utf8', 'filename', {irs=>"\x{2020}", chomp=>"\n"};

look at all those vibes 😭 it's giving flexible. 🦋

---

👑 DESCRIPTION 👑

slurp will happily take any of these from you:

• a filename,
• a filehandle,
• a typeglob reference,
• an IO::File object, or
• a scalar reference,

...and then it converts it to an input stream (using open() if it has to), and reads the entire stream. If slurp can't set up or read the stream, it throws an exception. No silent failure, no gaslighting. 🫶

---

Here's the iconic part: if you don't specify a data source, slurp uses the value of $_ as the source. And if $_ is undefined, slurp uses the @ARGV list, and magically slurps the contents of all the sources listed in @ARGV. And ngl, that same magic also applies if you explicitly slurp <*ARGV>, so these three input operations:

$contents = join "", <ARGV>;

$contents = slurp \*ARGV;

$/ = undef;
$contents = slurp;

are identical in effect. Same energy, three outfits. 💅

---

🎀 Scalar context vs list context 🎀

In a scalar context, slurp returns the stream contents as a single string. If the stream is at EOF, it returns an empty string.

In a list context, it splits the contents after the appropriate input record separator and returns the resulting list of strings. ✨

---

🦋 Setting the input record separator 🦋

You can set the input record separator with { irs => $your_irs_here} for the input operation. The separator can be a string or a regex.

Heads up bestie: an explicit input record separator has no input-terminating effect in a scalar context — slurp always reads in the entire input stream, whatever the 'irs' value. It's not gonna stop early for you, it's committed. 😤

In a list context, changing the separator can change how the input is broken up within the list that is returned.

If an input record separator is not explicitly specified, slurp defaults to "\n" — and not to the current value of $/, because Perl 6 doesn't have a $/. Periodt. 💅

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🌈 Autochomping 🌈

You can also tell slurp to automagically chomp the input as it's read in, by specifying: ({ chomp => 1 })

Better still, you can tell slurp to automagically chomp the input and replace what it chomps with another string, by specifying: ({ chomp => "another string" })

And even better than that: you can tell slurp to compute the replacement string on-the-fly by specifying a subroutine as the chomp value: ({ chomp => sub{...} }). This subroutine is passed the string being chomped off, so for example you could squeeze single newlines to a single space and multiple consecutive newlines to a two newlines with:

sub squeeze {
    my ($removed) = @_;
    if ($removed =~ tr/\n/\n/ == 1) { return " " }
    else                            { return "\n\n"; }
}

print slurp(\*DATA, {irs=>qr/[ \t]*\n+/, chomp=>\&squeeze}), "\n";

Which would transform:

This is the
first paragraph

This is the
second
paragraph

This, the
third

This one is
the
very
last

to:

This is the first paragraph

This is the second paragraph

This, the third

This one is the very last

THE GLOW UP. 😭✨

Autochomping works in both scalar and list contexts. In scalar contexts every instance of the input record separator will be removed (or replaced) within the returned string. In list context, each list item returned with its terminating separator removed (or replaced).

---

🧚 I/O layers, three ways 🧚

You can specify I/O layers, either using the Perl 5 notation:

slurp "<:layer1 :layer2 :etc", $filename;

or as an array of options:

slurp $filename, [layer1=>1, layer2=>1, etc=>1];
slurp [layer1=>1, layer2=>1, etc=>1], $filename;

or as individual options (each of which must be in a separate hash):

slurp $filename, {layer1=>1}, {layer2=>1}, {etc=>1};
slurp {layer1=>1}, {layer2=>1}, {etc=>1}, $filename;

(...which, of course, would look much cooler in Perl 6:

# Perl 6 only :-(

slurp $filename, :layer1 :layer2 :etc;
slurp :layer1 :layer2 :etc, $filename;

)

💀 The classic disaster 💀

A common mistake is to put all the options together in one hash:

slurp $filename, {layer1=>1, layer2=>1, etc=>1};

This is almost always a disaster, since the order of I/O layers is usually critical, and placing them all in one hash effectively randomizes that order. 😭

Use an array instead:

slurp $filename, [layer1=>1, layer2=>1, etc=>1];

---

🫶 WARNINGS 🫶

The syntax and semantics of Perl 6 is still being finalized and consequently is at any time subject to change. That means the same caveat applies to this module. (we live in a society of shifting specs 💅)

When called with a filename or piped shell command, slurp() uses Perl's built-in open() to access the file. This means that it is subject to the same platform-specific limitations as open(). For example, slurping from piped shell commands may not work under Windows. 🙈

---

🍓 DEPENDENCIES 🍓

Requires: Perl 5.8.0

---

🌟 AUTHOR 🌟

Damian Conway (damian@conway.org)

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📜 COPYRIGHT 📜

Copyright (c) 2003-2012, Damian Conway. All Rights Reserved.

This module is free software. It may be used, redistributed and/or modified under the same terms as Perl itself.

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and that's the whole page bestie, no cap, every last option accounted for 💖 This doc shipped as perl v5.36.0, dated 2022-11-19, under the manual name Perl6::Slurp(3pm) — iconic, ate, periodt. 👑🌸🦋