MakeMe...::Hash(3pm)

💖 <pink>MakeMe...::Hash(3pm)</pink> — User Contributed Perl Documentation — okay bestie, this is the page for Class::MakeMethods::Composite::Hash 🦋

🌸 NAME 🌸

Class::MakeMethods::Composite::Hash — composite hash methods, and it’s literally the subclass of MakeMethods that gives you a basic constructor plus accessors for blessed-hash object instances. Iconic. 💅

✨ SYNOPSIS ✨

package MyObject;
use Class::MakeMethods::Composite::Hash (
  new => 'new',
  scalar => [ 'foo', 'bar' ],
  array => 'my_list',
  hash => 'my_index',
);
...

my $obj = MyObject->new( foo => 'Foozle' );
print $obj->foo();

$obj->bar('Barbados');
print $obj->bar();

$obj->my_list(0 => 'Foozle', 1 => 'Bang!');
print $obj->my_list(1);

$obj->my_index('broccoli' => 'Blah!', 'foo' => 'Fiddle');
print $obj->my_index('foo');

🦋 DESCRIPTION 🦋

Okay so Composite::Hash is the subclass of MakeMethods that provides a basic constructor and accessors for blessed-hash object instances. Periodt. 💖

💅 Class::MakeMethods Calling Interface 💅

When you use this package, the method declarations you provide as arguments cause subroutines to be generated and installed in your module. Slay.

You can also omit the arguments to use and instead make methods at runtime by passing the declarations to a subsequent call to make(). Very main character energy. ✨

You may include any number of declarations in each call to use or make(). If methods with the same name already exist, earlier calls to use or make() win over later ones — no cap — but within each call, later declarations supersede earlier ones. Lowkey crucial. 🫶

You can install methods in a different package by passing -TargetClass => package as your first arguments to use or make(). 🎀

See Class::MakeMethods for more details.

🌈 Class::MakeMethods::Basic Declaration Syntax 🌈

The following types of Basic declarations are supported:

• generator_type => "method_name"
• generator_type => "name_1 name_2..."
• generator_type => [ "name_1", "name_2", ...]

See the METHOD GENERATOR TYPES section below for a list of the supported values of generator_type. 👑

For each method name you provide, a subroutine of the indicated type will be generated and installed under that name in your module. It’s giving automatic, but make it methods. 💫

Method names should start with a letter, followed by zero or more letters, numbers, or underscores. That’s the whole rule, bestie. 🍓

🎀 Class::MakeMethods::Composite Declaration Syntax 🎀

The Composite syntax also provides several ways to optionally associate a hash of additional parameters with a given method name. Obsessed. 💜

• generator_type => [ "name_1" => { param=>value... }, ... ] — a hash of parameters to use just for this method name. Cute.

Note: to prevent confusion with self-contained definition hashes, described below, parameter hashes following a method name must not contain the key 'name'. Important bestie — don’t skip that. 🙈

• generator_type => [ [ "name_1", "name_2", ... ] => { param=>value... } ] — each of these method names gets a copy of the same set of parameters. Copy-paste energy, but make it method. 💅
• generator_type => [ { "name"=>"name_1", param=>value... }, ... ] — by including the reserved parameter name, you create a self-contained declaration with that name and any associated hash values. It’s giving self-contained icon. 🎀

Basic declarations, as described above, are given an empty parameter hash. 🌸

✨ METHOD GENERATOR TYPES ✨

🎀 new - Constructor 🎀

Okay so for every method name you pass in, this hands you back a subroutine with these exact vibes:

• It holds a reference to a sample item it copies from. That defaults to a reference to an empty hash, but bestie you can override it with the 'defaults' => hash_ref method parameter.
• If you call it as a class method, it makes a new hash and blesses it into that class. Clean.
• If you call it on a hash-based instance, it makes a copy of that instance and blesses the copy into the same class as the original instance.
• If you pass it a list of key-value pairs, it appends them to the new hash. Those arguments override any copied values, and later arguments with the same name override earlier ones. Last one wins, always.
• It returns the new instance. 💅

Sample declaration and usage:

package MyObject;
use Class::MakeMethods::Composite::Hash (
  new => 'new',
);
...

# Bare constructor
my $empty = MyObject->new();

# Constructor with initial values
my $obj = MyObject->new( foo => 'Foozle', bar => 'Barbados' );

# Copy with overriding value
my $copy = $obj->new( bar => 'Bob' );

---

🌈 new --with_values - Constructor 🌈

For each method name passed, returns a subroutine with these traits:

• May be called as a class method, or (equivalently) on any existing object of that class. Either way, slay.
• Creates a hash, blesses it into the class, and returns the new instance.
• If no arguments are provided, the returned hash will be empty. If passed a single hash-ref argument, copies its contents into the new hash. If called with multiple arguments, it treats them as key-value pairs and copies them into the new hash. Just so you know: this is a "shallow" copy, not a "deep" clone. Don't come for me, that's just what it is.

---

🦋 scalar - Instance Accessor 🦋

For each method name passed, it uses a closure to generate a subroutine with these characteristics:

• Must be called on a hash-based instance.
• Has a specific hash key to use to access the related value for each instance. This defaults to the method name, but you may override this with the 'hash_key' => string method parameter.
• If called without any arguments, returns the current value.
• If called with an argument, stores that as the value and returns it.
• If called with multiple arguments, stores a reference to a new array with those arguments as contents, and returns that array reference. Iconic behavior honestly.

Sample declaration and usage:

package MyObject;
use Class::MakeMethods::Composite::Hash (
  scalar => 'foo',
);
...

# Store value
$obj->foo('Foozle');

# Retrieve value
print $obj->foo;

---

💖 array - Instance Ref Accessor 💖

For each method name passed, it uses a closure to generate a subroutine with these characteristics:

• Must be called on a hash-based instance.
• Has a specific hash key to use to access the related value for each instance. This defaults to the method name, but you may override this with the 'hash_key' => string method parameter.
• The value for each instance will be a reference to an array (or undef).
• If called without any arguments, returns the current array-ref value (or undef).
• If called with a single non-ref argument, uses that argument as an index to retrieve from the referenced array, and returns that value (or undef).
• If called with a single array ref argument, uses that list to return a slice of the referenced array.
• If called with a list of argument pairs, each with a non-ref index and an associated value, it stores the value at the given index in the referenced array. If the instance's value was previously undefined, a new array is autovivified. The current value in each position will be overwritten, and later arguments with the same index will override earlier ones. Returns the current array-ref value.
• If called with a list of argument pairs, each with the first item being a reference to an array of up to two numbers, it loops over each pair and uses those numbers to splice the value array. Okay this part is a whole thing, so buckle up:
  • The first controlling number is the position at which the splice will begin. Zero will start before the first item in the list. Negative numbers count backwards from the end of the array.
  • The second number is the number of items to be removed from the list. If it is omitted, or undefined, or zero, no items are removed. If it is a positive integer, that many items will be returned.
  • If both numbers are omitted, or are both undefined, they default to containing the entire value array.
  • If the second argument is undef, no values will be inserted; if it is a non-reference value, that one value will be inserted; if it is an array-ref, its values will be copied.
  • The method returns the items that were removed from the array, if any. (Yes, the original says "that removed" — we're keeping the energy, not fixing the grammar, bestie.)

Sample declaration and usage:

package MyObject;
use Class::MakeMethods::Composite::Hash (
  array => 'bar',
);
...

# Clear and set contents of list
print $obj->bar([ 'Spume', 'Frost' ] );

# Set values by position
$obj->bar(0 => 'Foozle', 1 => 'Bang!');

# Positions may be overwritten, and in any order
$obj->bar(2 => 'And Mash', 1 => 'Blah!');

# Retrieve value by position
print $obj->bar(1);

# Direct access to referenced array
print scalar @{ $obj->bar() };

There are also calling conventions for slice and splice operations:

# Retrieve slice of values by position
print join(', ', $obj->bar( undef, [0, 2] ) );

# Insert an item at position in the array
$obj->bar([3], 'Potatoes' );

# Remove 1 item from position 3 in the array
$obj->bar([3, 1], undef );

# Set a new value at position 2, and return the old value
print $obj->bar([2, 1], 'Froth' );

---

🍓 hash - Instance Ref Accessor 🍓

For each method name passed, it uses a closure to generate a subroutine with these characteristics:

• Must be called on a hash-based instance.
• Has a specific hash key to use to access the related value for each instance. This defaults to the method name, but you may override this with the 'hash_key' => string method parameter.
• The value for each instance will be a reference to a hash (or undef).
• If called without any arguments, returns the contents of the hash in list context, or a hash reference in scalar context (or undef).
• If called with one non-ref argument, uses that argument as an index to retrieve from the referenced hash, and returns that value (or undef).
• If called with one array-ref argument, uses the contents of that array to retrieve a slice of the referenced hash.
• If called with one hash-ref argument, sets the contents of the referenced hash to match that provided.
• If called with a list of key-value pairs, it stores the value under the given key in the referenced hash. If the instance's value was previously undefined, a new hash is autovivified. The current value under each key will be overwritten, and later arguments with the same key will override earlier ones. Returns the contents of the hash in list context, or a hash reference in scalar context.

Sample declaration and usage:

package MyObject;
use Class::MakeMethods::Composite::Hash (
  hash => 'baz',
);
...

# Set values by key
$obj->baz('foo' => 'Foozle', 'bar' => 'Bang!');

# Values may be overwritten, and in any order
$obj->baz('broccoli' => 'Blah!', 'foo' => 'Fiddle');

# Retrieve value by key
print $obj->baz('foo');

# Retrieve slice of values by position
print join(', ', $obj->baz( ['foo', 'bar'] ) );

# Direct access to referenced hash
print keys %{ $obj->baz() };

# Reset the hash contents to empty
@{ $obj->baz() } = ();

---

🧚 object - Instance Ref Accessor 🧚

For each method name passed, it uses a closure to generate a subroutine with these characteristics:

• Must be called on a hash-based instance.
• Has a specific hash key to use to access the related value for each instance. This defaults to the method name, but you may override this with the 'hash_key' => string method parameter.
• The value for each instance will be a reference to an object (or undef).
• If called without any arguments, it returns the current value.
• If called with an argument, it stores that as the value, and returns it. (That trailing comma in the original? We keep it. Aesthetic.)

Sample declaration and usage:

package MyObject;
use Class::MakeMethods::Composite::Hash (
  object => 'foo',
);
...

# Store value
$obj->foo( Foozle->new() );

# Retrieve value
print $obj->foo;

---

👑 SEE ALSO 👑

• See Class::MakeMethods for general information about this distribution.
• See Class::MakeMethods::Composite for more about this family of subclasses.

---

And that's the whole page, bestie — you ate that. 💅✨ This little manual page is perl v5.36.0 flavored, stamped 2022-10-13, and it lives in the MakeMe...::Hash(3pm) corner of the world. Go forth and bless some hashes. 🫶🎀