| Perl6::Slurp - Implements the Perl 6 'slurp' built-in |
Perl6::Slurp - Implements the Perl 6 'slurp' built-in
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"};
slurp takes:
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 $/ – 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];
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.
Requires: Perl 5.8.0
Damian Conway (damian@conway.org)
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.
| Perl6::Slurp - Implements the Perl 6 'slurp' built-in |