NAME¶
Perl6::Slurp - Implements the Perl 6 'slurp' built-in
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"};
DESCRIPTION¶
"slurp" takes:
- •
- a filename,
- •
- a filehandle,
- •
- a typeglob reference,
- •
- an IO::File object, or
- •
- a scalar reference,
converts it to an input stream (using "open()" if necessary), and
reads in the entire stream. If "slurp" fails to set up or read the
stream, it throws an exception.
If no data source is specified "slurp" uses the value of $_ as the
source. If $_ is undefined, "slurp" uses the @ARGV list, and
magically slurps the contents of
all the sources listed in @ARGV. Note
that the same magic is also applied if you explicitly slurp <*ARGV>, so
the following three input operations:
$contents = join "", <ARGV>;
$contents = slurp \*ARGV;
$/ = undef;
$contents = slurp;
are identical in effect.
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.
You can set the input record separator
("{ irs => $your_irs_here}") for the input
operation. The separator can be specified as a string or a regex. Note that 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.
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" (
not to the current value of $/ X since
Perl 6 doesn't
have a $/);
You can also tell "slurp" to automagically "chomp" the input
as it is read in, by specifying:
("{ chomp => 1 }")
Better still, you can tell "slurp" to automagically "chomp"
the input and
replace what it chomps with another string, by
specifying:
("{ chomp => "another string" }")
You can also tell "slurp" to compute the replacement string on-the-fly
by specifying a subroutine as the "chomp" value:
("{ chomp => sub{...} }"). This
subroutine is passed the string being chomped off, so for example you could
squeeze single newlines to a single space and multiple consecutive newlines to
a two newlines with:
sub squeeze {
my ($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
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).
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;
)
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.
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)
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.
