class Buf

class Buf does Positional { ... }

A Buf (short for buffer) is a binary string, and generally returned from low-level IO operations ($io.read($number-of-by)) or from Str.encode. It can be used to for writing to IO handles as $io.write($buf).

In the abstract it is just a list of integers, so for example indexing into a Buf with .[$idx] returns an Int.

Methods

new

method new(*@codes)

Creates a Buf from a list of integers.

Bool

multi method Bool(Buf:D:)

Returns False if and only if the buffer is empty.

elems

multi method elems(Buf:D:) returns Int:D

Returns the number of elements of the buffer.

decode

multi method decode(Buf:D: Str:D $encoding = 'UTF-8') returns Str:D

Applies an encoding to turn the buffer into a Str.

subbuf

method subbuf(Int $from, Int $len = self.elems) returns Buf:D

Extracts a part of the invocant buffer, starting from the index with elements $from, and taking $len elements (or less if the buffer is shorter), and creates a new buffer as the result.

say Buf.new(1..10).subbuf(2, 4);    # Buf:0x<03 04 05 06>
Full-size type graph image as SVG

Methods supplied by role Positional

Buf does role Positional, which provides the following methods:

of

method of()

Returns the type constraint for elements of the positional container. Defaults to Mu.

Methods supplied by class Any

Buf inherits from class Any, which provides the following methods:

ACCEPTS

multi method ACCEPTS(Any:D: Mu $other)

Returns True if $other === self (i.e. it checks object identity).

any

Interprets the invocant as a list and creates an any-Junction from it.

all

Interprets the invocant as a list and creates an all-Junction from it.

one

Interprets the invocant as a list and creates an one-Junction from it.

none

Interprets the invocant as a list and creates an none-Junction from it.

Methods supplied by class Mu

Buf inherits from class Mu, which provides the following methods:

defined

multi sub    defined(Mu) returns Bool:D
multi method defined()   returns Bool:D

Returns False on the type object, and True otherwise.

Bool

multi sub    Bool(Mu) returns Bool:D
multi method Bool()   returns Bool:D

Returns False on the type object, and True otherwise.

Str

multi method Str()   returns Str

Returns a string representation of the invocant, intended to be machine readable.

gist

multi sub    gist(Mu) returns Str
multi method gist()   returns Str

Returns a string representation of the invocant, optimized for fast recognition by humans.

The default gist method in Mu re-dispatches to the perl method, but many built-in classes override it to something more specific.

perl

multi sub    perl(Mu) returns Str
multi method perl()   returns Str

Returns a Perlish representation of the object (i.e., can usually be re-parsed to regenerate the object).

clone

method clone(*%twiddles)

Creates a shallow clone of the invocant. If named arguments are passed to it, their values are used in every place where an attribute name matches the name of a named argument.

new

multi method new(*%attrinit)

Default method for constructing (create + initialize) new objects of a class. This method expects only named arguments which are then used to initialize attributes with accessors of the same name.

Classes may provide their own new method to override this default.

bless

method bless(*%attrinit) returns Mu:D

Lower-level object construction method than new.

Creates a new object of the same type as the invocant, uses the named arguments to initialize attributes, and returns the created object.

You can use this method when writing custom constructors:

class Point {
    has $.x;
    has $.y;
    multi method new($x, $y) {
        self.bless(:$x, :$y);
    }
}
my $p = Point.new(-1, 1);

(Though each time you write a custom constructor, remember that it makes subclassing harder).

CREATE

method CREATE() returns Mu:D

Allocates a new object of the same type as the invocant, without initializing any attributes.

print

multi method print() returns Bool:D

Prints value to $*OUT after stringification using .Str method without newline at end.

say

multi method say() returns Bool:D

Prints value to $*OUT after stringification using .gist method with newline at end.

ACCEPTS

multi method ACCEPTS(Mu:U: $other)

Performs a type check. Returns True if $other conforms to the invocant (which is always a type object or failure).

This is the method that is triggered on smart-matching against type objects, for example in if $var ~~ Int { ... }.

WHICH

multi method WHICH() returns ObjAt:D

Returns an object of type ObjAt which uniquely identifies the object. Value types override this method which makes sure that two equivalent objects return the same return value from WHICH.