README

June 7, 2016 · View on GitHub

NAME

perl5i - Fix as much of Perl 5 as possible in one pragma

SYNOPSIS

  use perl5i::2;

  or

  $ perl5i your_script.pl

DESCRIPTION

Perl 5 has a lot of warts. There's a lot of individual modules and
techniques out there to fix those warts. perl5i aims to pull the best
of them together into one module so you can turn them on all at once.

This includes adding features, changing existing core functions and
changing defaults. It will likely not be 100% backwards compatible with
Perl 5, though it will be 99%, perl5i will try to have a lexical
effect.

Please add to this imaginary world and help make it real, either by
telling me what Perl looks like in your imagination
(http://github.com/evalEmpire/perl5i/issues) or make a fork (forking on
github is like a branch you control) and implement it yourself.

Rationale

Changing perl 5 core is a slow and difficult process. Perl 5 aims to be
compatible with ancient versions which means it is mostly stuck with
design, decisions and defaults made way back in the 90's.

There are modules in CPAN to solve or ease many of those issues but
many people don't know about them or don't know which ones to use.

Documentation and books are updated slowly and don't usually keep up;
this information becomes some sort of community knowledge, invisible
from the wider audience.

Even if you know a solution, having to decide everytime which module to
use and enable it individually might be enough for you to give up and
just do things the old way.

Perl5i brings all this community knowledge in a coherent way, in
something like 'the best of CPAN', enabled with a single command.

You don't need to know all it does nor how it does it, you just use
perl5i::2 on your code and you automatically get a modern environment,
with perl defaults, problems and inconsistencies fixed.

You can refer beginers to perl5i and they can benefit from it without
needing to become a perl guru first.

Using perl5i

Because perl5i plans to be incompatible in the future, you do not
simply use perl5i. You must declare which major version of perl5i you
are using. You do this like so:

    # Use perl5i major version 2
    use perl5i::2;

Thus the code you write with, for example, perl5i::2 will always remain
compatible even as perl5i moves on.

If you want to be daring, you can use perl5i::latest to get the latest
version. This will automatically happen if the program is -e. This lets
you do slightly less typing for one-liners like perl -Mperl5i -e ...

If you want your module to depend on perl5i, you should depend on the
versioned class. For example, depend on perl5i::2 and not perl5i.

See "VERSIONING" for more information about perl5i's versioning scheme.

What it does

perl5i enables each of these modules and adds/changes these functions.
We'll provide a brief description here, but you should look at each of
their documentation for full details.

The Meta Object

Every object (and everything is an object) now has a meta object
associated with it. Using the meta object you can ask things about the
object which were previously over complicated. For example...

    # the object's class
    my $class = $obj->mo->class;

    # its parent classes
    my @isa = $obj->mo->isa;

    # the complete inheritance hierarchy
    my @complete_isa = $obj->mo->linear_isa;

    # the reference type of the object
    my $reftype = $obj->mo->reftype;

A meta object is used to avoid polluting the global method space. mo
was chosen to avoid clashing with Moose's meta object.

See perl5i::Meta for complete details.

Subroutine and Method Signatures

perl5i makes it easier to declare what parameters a subroutine takes.

    func hello($place) {
        say "Hello, $place!\n";
    }

    method get($key) {
        return $self->{$key};
    }

    method new($class: %args) {
        return bless \%args, $class;
    }

func and method define subroutines as sub does, with some extra
conveniences.

The signature syntax is currently very simple. The content will be
assigned from @_. This:

    func add($this, $that) {
        return $this + $that;
    }

is equivalent to:

    sub add {
        my($this, $that) = @_;
        return $this + $that;
    }

method defines a method. This is the same as a subroutine, but the
first argument, the invocant, will be removed and made into $self.

    method get($key) {
        return $self->{$key};
    }

    sub get {
        my $self = shift;
        my($key) = @_;
        return $self->{$key};
    }

Methods have a special bit of syntax. If the first item in the
signature is $var: it will change the variable used to store the
invocant.

    method new($class: %args) {
        return bless \%args, $class;
    }

is equivalent to:

    sub new {
        my $class = shift;
        my %args = @_;
        return bless \%args, $class;
    }

Anonymous functions and methods work, too.

    my $code = func($message) { say $message };

Guarantees include:

  @_ will not be modified except by removing the invocant

Future versions of perl5i will add to the signature syntax and
capabilities. Planned expansions include:

  Signature validation
  Signature documentation
  Named parameters
  Required parameters
  Read only parameters
  Aliased parameters
  Anonymous method and function declaration
  Variable method and function names
  Parameter traits
  Traditional prototypes

See http://github.com/evalEmpire/perl5i/issues/labels/syntax#issue/19
for more details about future expansions.

The equivalencies above should only be taken for illustrative purposes,
they are not guaranteed to be literally equivalent.

Note that while all parameters are optional by default, the number of
parameters will eventually be enforced. For example, right now this
will work:

    func add($this, $that) { return $this + $that }

    say add(1,2,3);  # says 3

The extra argument is ignored. In future versions of perl5i this will
be a runtime error.

Signature Introspection

The signature of a subroutine defined with func or method can be
queried by calling the signature method on the code reference.

    func hello($greeting, $place) { say "$greeting, $place" }

    my $code = \&hello;
    say $code->signature->num_positional_params;  # prints 2

Functions defined with sub will not have a signature.

See perl5i::Signature for more details.

Autoboxing

autobox allows methods to be defined for and called on most unblessed
variables. This means you can call methods on ordinary strings, lists
and hashes! It also means perl5i can add a lot of functionality without
polluting the global namespace.

autobox::Core wraps a lot of Perl's built in functions so they can be
called as methods on unblessed variables. @a->pop for example.

alias

    $scalar_reference->alias( @identifiers );
    @alias->alias( @identifiers );
    %hash->alias( @identifiers );
    (\&code)->alias( @identifiers );

Aliases a variable to a new global name.

    my $code = sub { 42 };
    $code->alias( "foo" );
    say foo();        # prints 42

It will work on everything except scalar references.

    our %stuff;
    %other_hash->alias( "stuff" );  # %stuff now aliased to %other_hash

It is not a copy, changes to one will change the other.

    my %things = (foo => 23);
    our %stuff;
    %things->alias( "stuff" );  # alias %things to %stuff
    $stuff{foo} = 42;           # change %stuff
    say $things{foo};           # and it will show up in %things

Multiple @identifiers will be joined with '::' and used as the fully
qualified name for the alias.

    my $class = "Some::Class";
    my $name  = "foo";
    sub { 99 }->alias( $class, $name );
    say Some::Class->foo;  # prints 99

If there is just one @identifier and it has no "::" in it, the current
caller will be prepended. $thing->alias("name") is shorthand for
$thing->alias(CLASS, "name")

Due to limitations in autobox, non-reference scalars cannot be aliased.
Alias a scalar ref instead.

    my $thing = 23;
    $thing->alias("foo");  # error

    my $thing = \23;
    $thing->alias("foo");  # $foo is now aliased to $thing

This is basically a nicer way to say:

    no strict 'refs';
    *{$package . '::'. $name} = $reference;

Scalar Autoboxing

All of the methods provided by autobox::Core are available from perl5i.

in addition, perl5i adds some methods of its own.

path

    my $object = $path->path;

Creates a Path::Tiny $object for the given file or directory $path.

    my $path = "/foo/bar/baz.txt"->path;
    my $content = $path->slurp;

center

    my $centered_string = $string->center($length);
    my $centered_string = $string->center($length, $character);

Centers $string between $character. $centered_string will be of length
$length.

$character defaults to " ".

    say "Hello"->center(10);        # "   Hello  ";
    say "Hello"->center(10, '-');   # "---Hello--";

center() will never truncate $string. If $length is less than
$string->length it will just return $string.

    say "Hello"->center(4);        # "Hello";

round

    my $rounded_number = $number->round;

Round to the nearest integer.

round_up

ceil

    my $new_number = $number->round_up;

Rounds the $number towards infinity.

    2.45->round_up;   # 3
  (-2.45)->round_up;  # -2

ceil() is a synonym for round_up().

round_down

floor

    my $new_number = $number->round_down;

Rounds the $number towards negative infinity.

    2.45->round_down;  # 2
  (-2.45)->round_down; # -3

floor() is a synonyn for round_down().

is_number

    $is_a_number = $thing->is_number;

Returns true if $thing is a number understood by Perl.

    12.34->is_number;           # true
    "12.34"->is_number;         # also true
    "eleven"->is_number;        # false

is_positive

    $is_positive = $thing->is_positive;

Returns true if $thing is a positive number.

0 is not positive.

is_negative

    $is_negative = $thing->is_negative;

Returns true if $thing is a negative number.

0 is not negative.

is_even

    $is_even = $thing->is_even;

Returns true if $thing is an even integer.

is_odd

    $is_odd = $thing->is_odd;

Returns true if $thing is an odd integer.

is_integer

    $is_an_integer = $thing->is_integer;

Returns true if $thing is an integer.

    12->is_integer;             # true
    12.34->is_integer;          # false
    "eleven"->is_integer;       # false

is_int

A synonym for is_integer

is_decimal

    $is_a_decimal_number = $thing->is_decimal;

Returns true if $thing is a decimal number.

    12->is_decimal;             # false
    12.34->is_decimal;          # true
    ".34"->is_decimal;          # true
    "point five"->is_decimal;   # false

require

    my $module = $module->require;

Will require the given $module. This avoids funny things like eval
qq[require $module] or die $@. It accepts only module names.

On failure it will throw an exception, just like require. On a success
it returns the $module. This is mostly useful so that you can
immediately call $module's import method to emulate a use.

    # like "use $module qw(foo bar);" if that worked
    $module->require->import(qw(foo bar));

    # like "use $module;" if that worked
    $module->require->import;

wrap

    my $wrapped = $string->wrap( width => $cols, separator => $sep );

Wraps $string to width $cols, breaking lines at word boundries using
separator $sep.

If no width is given, $cols defaults to 76. Default line separator is
the newline character "\n".

See Text::Wrap for details.

ltrim

rtrim

trim

    my $trimmed = $string->trim;
    my $trimmed = $string->trim($character_set);

Trim whitespace. ltrim() trims off the start of the string (left),
rtrim() off the end (right) and trim() off both the start and end.

    my $string = '    testme'->ltrim;        # 'testme'
    my $string = 'testme    '->rtrim;        # 'testme'
    my $string = '    testme    '->trim;     # 'testme'

They all take an optional $character_set which will determine what
characters should be trimmed. It follows regex character set syntax so
A-Z will trim everything from A to Z. Defaults to \s, whitespace.

    my $string = '-> test <-'->trim('-><');  # ' test '

title_case

    my $name = 'joe smith'->title_case;   # Joe Smith

Will uppercase every word character that follows a wordbreak character.

path2module

    my $module = $path->path2module;

Given a relative $path it will return the Perl module this represents.
For example,

    "Foo/Bar.pm"->path2module;  # "Foo::Bar"

It will throw an exception if given something which could not be a path
to a Perl module.

module2path

    my $path = $module->module2path;

Will return the relative $path in which the Perl $module can be found.
For example,

    "Foo::Bar"->module2path;  # "Foo/Bar.pm"

is_module_name

    my $is_valid = $string->is_module_name;

Will return true if the $string is a valid module name.

    "Foo::Bar"->is_module_name;  # true
    "Foo/Bar"->is_module_name;   # false

group_digits

    my $number_grouped     = $number->group_digits;
    my $number_grouped     = $number->group_digits(\%options);

Turns a number like 1234567 into a string like 1,234,567 known as
"digit grouping".

It honors your current locale to determine the separator and grouping.
This can be overridden using %options.

NOTE: many systems do not have their numeric locales set properly

separator

  The character used to separate groups. Defaults to "thousands_sep" in
  your locale or "," if your locale doesn't specify.

decimal_point

  The decimal point character. Defaults to "decimal_point" in your
  locale or "." if your locale does not specify.

grouping

  How many numbers in a group? Defaults to "grouping" in your locale or
  3 if your locale doesn't specify.

  Note: we don't honor the full grouping locale, its a wee bit too
  complicated.

currency

  If true, it will treat the number as currency and use the monetary
  locale settings. "mon_thousands_sep" instead of "thousands_sep" and
  "mon_grouping" instead of "grouping".

    1234->group_digits;                      # 1,234 (assuming US locale)
    1234->group_digits( separator => "." );  # 1.234

commify

    my $number_grouped = $number->commify;
    my $number_grouped = $number->commify(\%options);

commify() is just like group_digits() but it is not locale aware. It is
useful when you want a predictable result regardless of the user's
locale settings.

%options defaults to ( separator => ",", grouping => 3, decimal_point
=> "." ). Each key will be overridden individually.

    1234->commify;                      # 1,234
    1234->commify({ separator => "." });  # 1.234

reverse

    my $reverse = $string->reverse;

Reverses a $string.

Unlike Perl's reverse(), this always reverses the string regardless of
context.

Array Autoboxing

The methods provided by "Array Methods" in autobox::Core are available
from perl5i.

All the functions from List::Util and select ones from List::MoreUtils
are all available as methods on unblessed arrays and array refs: first,
max, maxstr, min, minstr, minmax, shuffle, reduce, sum, any, all, none,
true, false, uniq and mesh.

They have all been altered to return array refs where applicable in
order to allow chaining.

    @array->grep(sub{ $_->is_number })->sum->say;

foreach

    @array->foreach( func($item) { ... } );

Works like the built in foreach, calls the code block for each element
of @array passing it into the block.

    @array->foreach( func($item) { say $item } );  # print each item

It will pass in as many elements as the code block accepts. This allows
you to iterate through an array 2 at a time, or 3 or 4 or whatever.

    my @names = ("Joe", "Smith", "Jim", "Dandy", "Jane", "Lane");
    @names->foreach( func($fname, $lname) {
        say "Person: $fname $lname";
    });

A normal subroutine with no signature will get one at a time.

If @array is not a multiple of the iteration (for example, @array has 5
elements and you ask 2 at a time) the behavior is currently undefined.

as_hash

    my %hash = @array->as_hash;

This method returns a %hash where each element of @array is a key. The
values are all true. Its functionality is similar to:

    my %hash = map { $_ => 1 } @array;

Example usage:

    my @array = ("a", "b", "c");
    my %hash = @array->as_hash;
    say q[@array contains 'a'] if $hash{"a"};

pick

    my @rand = @array->pick($number);

The pick() method returns a list of $number elements in @array. If
$number is larger than the size of the list, it returns the entire list
shuffled.

Example usage:

    my @array = (1, 2, 3, 4);
    my @rand = @array->pick(2);

pick_one

    my $rand = @array->pick_one;

The pick_one() method returns a random element in @array. It is similar
to @array->pick(1), except that it does not return a list.

Example usage:

    my @array = (1,2,3,4);
    my $rand = @array->pick_one;

diff

Calculate the difference between two (or more) arrays:

    my @a = ( 1, 2, 3 );
    my @b = ( 3, 4, 5 );

    my @diff_a = @a->diff(\@b) # [ 1, 2 ]
    my @diff_b = @b->diff(\@a) # [ 4, 5 ]

Diff returns all elements in array @a that are not present in array @b.
Item order is not considered: two identical elements in both arrays
will be recognized as such disregarding their index.

    [ qw( foo bar ) ]->diff( [ qw( bar foo ) ] ) # empty, they are equal

For comparing more than two arrays:

    @a->diff(\@b, \@c, ... )

All comparisons are against the base array (@a in this example). The
result will be composed of all those elements that were present in @a
and in none other.

It also works with nested data structures; it will traverse them
depth-first to assess whether they are identical or not. For instance:

    [ [ 'foo ' ], { bar => 1 } ]->diff([ 'foo' ]) # [ { bar => 1 } ]

In the case of overloaded objects (i.e., DateTime, URI, Path::Class,
etc.), it tries its best to treat them as strings or numbers.

    my $uri  = URI->new("http://www.perl.com");
    my $uri2 = URI->new("http://www.perl.com");

    [ $uri ]->diff( [ "http://www.perl.com" ] ); # empty, they are equal
    [ $uri ]->diff( [ $uri2 ] );                 # empty, they are equal

popn

    my @newarray = @array->popn($n);

Pops $n values from the @array.

If $n is greater than the length of @array, it will return the whole
@array. If $n is 0, it will return an empty array.

A negative $n or non-integer is an error.

    my @array = (1, 2, 3, 4, 5);
    my @newarray = @array->popn(3); # (3, 4, 5)

shiftn

       my @newarray = @array->shiftn($n);

Works like popn, but it shifts off the front of the array instead of
popping off the end.

    my @array = (1, 2, 3, 4, 5);
    my @newarray = @array->shiftn(3); # (1, 2, 3)

intersect

    my @a = (1 .. 10);
    my @b = (5 .. 15);

    my @intersection = @a->intersect(\@b) # [ 5 .. 10 ];

Performs intersection between arrays, returning those elements that are
present in all of the argument arrays simultaneously.

As with diff(), it works with any number of arrays, nested data
structures of arbitrary depth, and handles overloaded objects
graciously.

ltrim

rtrim

trim

    my @trimmed = @list->trim;
    my @trimmed = @list->trim($character_set);

Trim whitespace from each element of an array. Each works just like
their scalar counterpart.

    my @trimmed = [ '   foo', 'bar   ' ]->ltrim;  # [ 'foo', 'bar   ' ]
    my @trimmed = [ '   foo', 'bar   ' ]->rtrim;  # [ '   foo', 'bar' ]
    my @trimmed = [ '   foo', 'bar   ' ]->trim;   # [ 'foo', 'bar'    ]

As with the scalar trim() methods, they all take an optional
$character_set which will determine what characters should be trimmed.

    my @trimmed = ['-> foo <-', '-> bar <-']->trim('-><'); # [' foo ', ' bar ']

Hash Autoboxing

All of the methods provided by "Hash Methods" in autobox::Core are
available from perl5i.

In addition...

each

Iterate through each key/value pair in a hash using a callback.

    my %things = ( foo => 23, bar => 42 );
    %things->each( func($k, $v) {
        say "Key: $k, Value: $v"
    });

Unlike the each function, individual calls to each are guaranteed to
iterate through the entirety of the hash.

flip

Exchanges values for keys in a hash.

    my %things = ( foo => 1, bar => 2, baz => 5 );
    my %flipped = %things->flip; # { 1 => foo, 2 => bar, 5 => baz }

If there is more than one occurrence of a certain value, any one of the
keys may end up as the value. This is because of the random ordering of
hash keys.

    # Could be { 1 => foo }, { 1 => bar }, or { 1 => baz }
    { foo => 1, bar => 1, baz => 1 }->flip;

Because hash references cannot usefully be keys, it will not work on
nested hashes.

    { foo => [ 'bar', 'baz' ] }->flip; # dies

merge

Recursively merge two or more hashes together using
Hash::Merge::Simple.

    my $a = { a => 1 };
    my $b = { b => 2, c => 3 };

    $a->merge($b); # { a => 1, b => 2, c => 3 }

For conflicting keys, rightmost precedence is used:

    my $a = { a => 1 };
    my $b = { a => 100, b => 2};

    $a->merge($b); # { a => 100, b => 2 }
    $b->merge($a); # { a => 1,   b => 2 }

It also works with nested hashes, although it won't attempt to merge
array references or objects. For more information, look at the
Hash::Merge::Simple docs.

diff

    my %staff    = ( bob => 42, martha => 35, timmy => 23 );
    my %promoted = ( timmy => 23 );

    %staff->diff(\%promoted); # { bob => 42, martha => 35 }

Returns the key/value pairs present in the first hash that are not
present in the subsequent hash arguments. Otherwise works as
@array->diff.

intersect

    %staff->intersect(\%promoted); # { timmy => 23 }

Returns the key/value pairs that are present simultaneously in all the
hash arguments. Otherwise works as @array->intersect.

Code autoboxing

signature

    my $sig = $code->signature;

You can query the signature of any code reference defined with func or
method. See "Signature Introspection" for details.

If $code has a signature, returns an object representing $code's
signature. See perl5i::Signature for details. Otherwise it returns
nothing.

caller

Perl6::Caller causes caller to return an object in scalar context.

die

die now always returns an exit code of 255 instead of trying to use $!
or $? which makes the exit code unpredictable. If you want to exit with
a message and a special exit code, use warn then exit.

list

list will force list context similar to how scalar will force scalar
context.

utf8::all

perl5i turns on utf8::all which turns on all the Unicode features of
Perl it can.

Here is the current list, more may be turned on later.

Bare strings in your source code are now UTF8. This means UTF8 variable
and method names, strings and regexes.

    my $message = "انا لا اتكلم العربيه";
    my $τάδε    = "It's all Greek to me!";
    sub fünkßhüñ { ... }

Strings will be treated as a set of characters rather than a set of
bytes. For example, length will return the number of characters, not
the number of bytes.

    length("perl5i is MËTÁŁ");  # 15, not 18

@ARGV will be read as UTF8.

STDOUT, STDIN, STDERR and all newly opened filehandles will have UTF8
encoding turned on. Consequently, if you want to output raw bytes to a
file, such as outputting an image, you must set binmode $fh.

capture

    my($stdout, $stderr) = capture { ... } %options;
    my $stdout = capture { ... } %options;

capture() lets you capture all output to STDOUT and STDERR in any block
of code.

    # $out = "Hello"
    # $err = "Bye"
    my($out, $err) = capture {
        print "Hello";
        print STDERR "Bye";
    };

If called in scalar context, it will only return STDOUT and silence
STDERR.

    # $out = "Hello"
    my $out = capture {
        print "Hello";
        warn "oh god";
    };

capture takes some options.

tee

  tee will cause output to be captured yet still printed.

      my $out = capture { print "Hi" } tee => 1;

merge

  merge will merge STDOUT and STDERR into one variable.

      # $out = "HiBye"
      my $out = capture {
          print "Hi";
          print STDERR "Bye";
      } merge => 1;

Carp

croak and carp from Carp are always available.

The Carp message will always format consistently, smoothing over the
backwards incompatible change in Carp 1.25.

Child

Child provides the child function which is a better way to do forking.

child creates and starts a child process, and returns an
Child::Link::Proc object which is a better interface for managing the
child process. The only required argument is a codeblock, which is
called in the new process. exit() is automatically called for you after
the codeblock returns.

    my $proc = child {
        my $parent = shift;
        ...
    };

You can also request a pipe for IPC:

    my $proc = child {
        my $parent = shift;

        $parent->say("Message");
        my $reply = $parent->read();

        ...
    } pipe => 1;

    my $message = $proc->read();
    $proc->say("reply");

See Child for more information.

English

English gives English names to the punctuation variables; for instance,
<$@> is also <$EVAL_ERROR>. See perlvar for details.

It does not load the regex variables which affect performance.
$PREMATCH, $MATCH, and $POSTMATCH will not exist. See the p modifier in
perlre for a better alternative.

Modern::Perl

Modern::Perl turns on strict and warnings, enables all the 5.10
features like given/when, say and state, and enables C3 method
resolution order.

CLASS

Provides CLASS and $CLASS alternatives to __PACKAGE__.

File::chdir

File::chdir gives you $CWD representing the current working directory
and it's assignable to chdir. You can also localize it to safely chdir
inside a scope.

File::stat

File::stat causes stat to return an object in scalar context.

DateTime

time, localtime, and gmtime are replaced with DateTime objects. They
will all act like the core functions.

    # Sat Jan 10 13:37:04 2004
    say scalar gmtime(2**30);

    # 2004
    say gmtime(2**30)->year;

    # 2009 (when this was written)
    say time->year;

Time::y2038

gmtime() and localtime() will now safely work with dates beyond the
year 2038 and before 1901. The exact range is not defined, but we
guarantee at least up to 2**47 and back to year 1.

IO::Handle

Turns filehandles into objects so you can call methods on them. The
biggest one is autoflush rather than mucking around with $| and select.

    $fh->autoflush(1);

autodie

autodie causes system and file calls which can fail (open, system, and
chdir, for example) to die when they fail. This means you don't have to
put or die at the end of every system call, but you do have to wrap it
in an eval block if you want to trap the failure.

autodie's default error messages are pretty smart.

All of autodie will be turned on.

autovivification

autovivification fixes the bug/feature where this:

    $hash = {};
    $hash->{key1}{key2};

Results in $hash->{key1} coming into existence. That will no longer
happen.

No indirect object syntax

perl5i turns indirect object syntax, ie. new $obj, into a compile time
error. Indirect object syntax is largely unnecessary and removing it
avoids a number of ambiguous cases where Perl will mistakenly try to
turn a function call into an indirect method call.

See indirect for details.

want

want() generalizes the mechanism of the wantarray function, allowing a
function to determine the context it's being called in. Want
distinguishes not just scalar v. array context, but void, lvalue,
rvalue, boolean, reference context, and more. See perldoc Want for full
details.

Try::Tiny

Try::Tiny gives support for try/catch blocks as an alternative to eval
BLOCK. This allows correct error handling with proper localization of
$@ and a nice syntax layer:

        # handle errors with a catch handler
        try {
                die "foo";
        } catch {
                warn "caught error: $_";
        };

        # just silence errors
        try {
                die "foo";
        };

See perldoc Try::Tiny for details.

true

You no longer have to put a true value at the end of a module which
uses perl5i.

Better load errors

Most of us have learned the meaning of the dreaded "Can't locate Foo.pm
in @INC". Admittedly though, it's not the most helpful of the error
messages. In perl5i we provide a much friendlier error message.

Example:

    Can't locate My/Module.pm in your Perl library.  You may need to install it
    from CPAN or another repository.  Your library paths are:
        Indented list of paths, 1 per line...

Turning off features

    use perl5i::2 -skip => \@features_to_skip;

While perl5i is intended as a curated collection of modules, its
possible you might not want certain features. Features can be turned
off in your scope by using -skip.

For example, this will skip loading Try::Tiny.

    use perl5i::latest -skip => [qw(Try::Tiny)];

Why would you do this? You might want to use a different try/catch
module such as TryCatch which provides its own try and catch.

The feature strings are: autobox, autodie, autovivification, capture,
Carp::Fix::1_25, Child, CLASS, die, English, File::chdir, indirect,
list, Meta, Modern::Perl, Perl6::Caller, Signatures, stat, time, true,
Try::Tiny, utf8::all, Want.

Command line program

There is a perl5i command line program installed with perl5i (Windows
users get perl5i.bat). This is handy for writing one liners.

    perl5i -e 'gmtime->year->say'

And you can use it on the #! line.

    #!/usr/bin/perl5i

    gmtime->year->say;

If you write a one-liner without using this program, saying -Mperl5i
means -Mperl5i::latest. Please see "Using perl5i" and "VERSIONING" for
details.

BUGS

Some parts are not lexical. Some parts are package scoped.

If you're going to use two versions of perl5i together, we do not
currently recommend having them in the same package.

See http://github.com/evalEmpire/perl5i/issues/labels/bug for a
complete list.

Please report bugs at http://github.com/evalEmpire/perl5i/issues/.

VERSIONING

perl5i follows the Semantic Versioning policy, http://semver.org. In
short...

Versions will be of the form X.Y.Z.

0.Y.Z may change anything at any time.

Incrementing X (ie. 1.2.3 -> 2.0.0) indicates a backwards incompatible
change.

Incrementing Y (ie. 1.2.3 -> 1.3.0) indicates a new feature.

Incrementing Z (ie. 1.2.3 -> 1.2.4) indicates a bug fix or other
internal change.

NOTES

Inspired by chromatic's Modern::Perl and in particular
http://www.modernperlbooks.com/mt/2009/04/ugly-perl-a-lesson-in-the-importance-of-language-design.html.

I totally didn't come up with the "Perl 5 + i" joke. I think it was
Damian Conway.

THANKS

Thanks to our contributors: Chas Owens, Darian Patrick, rjbs,
chromatic, Ben Hengst, Bruno Vecchi and anyone else I've forgotten.

Thanks to Flavian and Matt Trout for their signature and Devel::Declare
work.

Thanks to all the CPAN authors upon whom this builds.

LICENSE

Copyright 2009-2010, Michael G Schwern <schwern@pobox.com>

This program is free software; you can redistribute it and/or modify it
under the same terms as Perl itself.

See http://dev.perl.org/licenses/artistic.html