Interfacing Raku to Gnome GTK+

Gnome::GObject::Value

Standard Parameter and Value Types

Description

This class provides an abstract container structure which can be copied, transformed and compared while holding a value of any (derived) type, which is registered as a GType with a GTypeValueTable in its GTypeInfo structure. Parameter specifications for most value types can be created as GParamSpec derived instances, to implement e.g. GObject properties which operate on GValue containers. (note that not everything is implemented in Raku)

Parameter names need to start with a letter (a-z or A-Z). Subsequent characters can be letters, numbers or a ‘-‘. All other characters are replaced by a ‘-‘ during construction.

N-GValue is a polymorphic type that can hold values of any other type operations and thus can be used as a type initializer for new(:$init) and are defined by a separate interface. See the standard values API for details

The N-GValue structure is basically a variable container that consists of a type identifier and a specific value of that type. The type identifier within a N-GValue structure always determines the type of the associated value. To create an undefined N-GValue structure, simply create a zero-filled N-GValue structure. To initialize the N-GValue, use the new(:$init) function. A N-GValue cannot be used until it is initialized. The basic type operations (such as freeing and copying) are determined by the GTypeValueTable associated with the type ID stored in the N-GValue. Other N-GValue operations (such as converting values between types) are provided by this interface.

Synopsis

Declaration

unit class Gnome::GObject::Value;
also is Gnome::GObject::Boxed;

Uml Diagram

Types

N-GValue

A structure to hold a type and a value.

coment

Its type is readable from the structure as a 32 bit integer and holds type values like G_TYPE_UCHAR and G_TYPE_LONG.

Dynamic types from native widgets are also stored. The static type names like G_TYPE_UCHAR and G_TYPE_LONG, are defined in Gnome::GObject::Type.

Methods

new

:init

Create a value object and initialize to type. Exampes of a type is G_TYPE_INT or G_TYPE_BOOLEAN.

multi method new ( Int :$init! )

:type, :value

Create a value object and initialize to type and set a value.

multi method new ( Int :$type!, Any :$value! )

:gvalue

Create an object using a native object from elsewhere.

multi method new ( N-GValue :$gvalue! )

:native-object

Create an object using a native object from elsewhere. See also Gnome::N::TopLevelSupportClass.

multi method new ( N-GValue :$native-object! )

copy, copy-rk

Copies the value of this Value object.

method copy ( --> N-GValue )
method copy-rk ( --> Gnome::GObject::Value )
  • N-GValue $dest_value; An initialized Gnome::GObject::Value structure of the same type as src-value.

get-boolean

Get the contents of a G-TYPE-BOOLEAN Gnome::GObject::Value.

Returns: boolean contents of value

method get-boolean ( --> Bool )

get-double

Get the contents of a G-TYPE-DOUBLE Gnome::GObject::Value.

Returns: double contents of value

method get-double ( --> Num )

get-enum

Get the contents of a G-TYPE-ENUM Gnome::GObject::Value.

method get-enum ( --> Int )

get-flags

Get the contents of a G-TYPE-FLAGS Gnome::GObject::Value.

Returns: flags contents of value

method get-flags ( --> UInt )

get-float

Get the contents of a G-TYPE-FLOAT Gnome::GObject::Value.

Returns: float contents of value

method get-float ( --> Num )

get-gtype

Get the contents of a G-TYPE-GTYPE Gnome::GObject::Value.

Returns: the Gnome::GObject::Type stored in value

method get-gtype ( --> N-GValue )

get-int

Get the contents of a G-TYPE-INT Gnome::GObject::Value.

Returns: integer contents of value

method get-int ( --> Int )

get-int64

Get the contents of a G-TYPE-INT64 Gnome::GObject::Value.

Returns: 64bit integer contents of value

method get-int64 ( --> Int )

get-long

Get the contents of a G-TYPE-LONG Gnome::GObject::Value.

Returns: long integer contents of value

method get-long ( --> Int )

get-pointer

Get the contents of a pointer Gnome::GObject::Value.

Returns: pointer contents of value

method get-pointer ( --> Pointer )

get-schar

Get the contents of a G-TYPE-CHAR Gnome::GObject::Value.

Returns: signed 8 bit integer contents of value

method get-schar ( --> Int )

get-string

Get the contents of a G-TYPE-STRING Gnome::GObject::Value.

Returns: string content of value

method get-string ( --> Str )

get-uchar

Get the contents of a G-TYPE-UCHAR Gnome::GObject::Value.

Returns: unsigned character contents of value

method get-uchar ( --> UInt )

get-uint

Get the contents of a G-TYPE-UINT Gnome::GObject::Value.

Returns: unsigned integer contents of value

method get-uint ( --> UInt )

get-uint64

Get the contents of a G-TYPE-UINT64 Gnome::GObject::Value.

Returns: unsigned 64bit integer contents of value

method get-uint64 ( --> UInt )

get-ulong

Get the contents of a G-TYPE-ULONG Gnome::GObject::Value.

Returns: unsigned long integer contents of value

method get-ulong ( --> UInt )

get-variant

Get the contents of a variant Gnome::GObject::Value.

Returns: variant contents of value (may be undefined)

method get-variant ( --> N-GValue )

reset

Clears the current value in value and resets it to the default value (as if the value had just been initialized).

Returns: the Gnome::GObject::Value structure that has been passed in

method reset ( --> N-GValue )

set-boolean

Set the contents of a G-TYPE-BOOLEAN Gnome::GObject::Value to v-boolean.

method set-boolean ( Bool $v_boolean )
  • Bool $v_boolean; boolean value to be set

set-double

Set the contents of a G-TYPE-DOUBLE Gnome::GObject::Value to v-double.

method set-double ( Num() $v_double )
  • Num() $v_double; double value to be set

set-enum

Set the contents of a G-TYPE-ENUM Gnome::GObject::Value to v-enum.

method set-enum ( Int() $v_enum )
  • Int() $v_enum; enum value to be set

set-flags

Set the contents of a G-TYPE-FLAGS Gnome::GObject::Value to v-flags.

method set-flags ( UInt $v_flags )
  • UInt $v_flags; flags value to be set

set-float

Set the contents of a G-TYPE-FLOAT Gnome::GObject::Value to v-float.

method set-float ( Num() $v_float )
  • Num() $v_float; float value to be set

set-gtype

Set the contents of a G-TYPE-GTYPE Gnome::GObject::Value to v-gtype.

method set-gtype ( N-GValue $v_gtype )
  • N-GValue $v_gtype; Gnome::GObject::Type to be set

set-int

Set the contents of a G-TYPE-INT Gnome::GObject::Value to v-int.

method set-int ( Int() $v_int )
  • Int() $v_int; integer value to be set

set-int64

Set the contents of a G-TYPE-INT64 Gnome::GObject::Value to v-int64.

method set-int64 ( Int() $v_int64 )
  • Int() $v_int64; 64bit integer value to be set

set-long

Set the contents of a G-TYPE-LONG Gnome::GObject::Value to v-long.

method set-long ( Int() $v_long )
  • Int() $v_long; long integer value to be set

set-pointer

Set the contents of a pointer Gnome::GObject::Value to v-pointer.

method set-pointer ( Pointer $v_pointer )
  • Pointer $v_pointer; pointer value to be set

set-schar

Set the contents of a G-TYPE-CHAR Gnome::GObject::Value to v-char.

method set-schar ( Int() $v_char )
  • Int() $v_char; signed 8 bit integer to be set

set-string

Set the contents of a G-TYPE-STRING Gnome::GObject::Value to v-string.

method set-string ( Str $v_string )
  • Str $v_string; caller-owned string to be duplicated for the Gnome::GObject::Value

set-uchar

Set the contents of a G-TYPE-UCHAR Gnome::GObject::Value to v-uchar.

method set-uchar ( UInt $v_uchar )
  • UInt $v_uchar; unsigned character value to be set

set-uint

Set the contents of a G-TYPE-UINT Gnome::GObject::Value to v-uint.

method set-uint ( UInt $v_uint )
  • UInt $v_uint; unsigned integer value to be set

set-uint64

Set the contents of a G-TYPE-UINT64 Gnome::GObject::Value to v-uint64.

method set-uint64 ( UInt $v_uint64 )
  • UInt $v_uint64; unsigned 64bit integer value to be set

set-ulong

Set the contents of a G-TYPE-ULONG Gnome::GObject::Value to v-ulong.

method set-ulong ( UInt $v_ulong )
  • UInt $v_ulong; unsigned long integer value to be set

set-variant

Set the contents of a variant Gnome::GObject::Value to variant. If the variant is floating, it is consumed.

method set-variant ( N-GValue $variant )
  • N-GValue $variant; a Gnome::GObject::Variant, or undefined

take-string

Sets the contents of a G-TYPE-STRING Gnome::GObject::Value to v-string.

method take-string ( Str $v_string )
  • Str $v_string; string to take ownership of

take-variant

Set the contents of a variant Gnome::GObject::Value to variant, and takes over the ownership of the caller’s reference to variant; the caller doesn’t have to unref it any more (i.e. the reference count of the variant is not increased).

If variant was floating then its floating reference is converted to a hard reference.

If you want the Gnome::GObject::Value to hold its own reference to variant, use set-variant() instead.

This is an internal function introduced mainly for C marshallers.

method take-variant ( N-GValue $variant )
  • N-GValue $variant; a Gnome::GObject::Variant, or undefined

transform

Tries to cast the contents of this into a type appropriate to store in $dest-value, e.g. to transform a G-TYPE-INT value into a G-TYPE-FLOAT value. Performing transformations between value types might incur precision lossage. Especially transformations into strings might reveal seemingly arbitrary results and shouldn’t be relied upon for production code (such as rcfile value or object property serialization).

Returns: Whether a transformation rule was found and could be applied. Upon failing transformations, $dest-value is left untouched.

method transform ( N-GValue $dest_value --> Bool )
  • N-GValue $dest_value; Target value.

type-compatible

Returns whether a N-GValue of type $src-type can be copied into a -GValue of type $dest-type.

Returns: True if copy() is possible with src-type and dest-type.

method type-compatible ( UInt $src_type, UInt $dest_type --> Bool )

  • UInt $src_type; source type to be copied.

  • UInt $dest_type; destination type for copying.

type-transformable

Check whether transform() is able to transform values of type src-type into values of type dest-type. Note that for the types to be transformable, they must be compatible or a transformation function must be registered.

Returns: True if the transformation is possible, False otherwise.

method type-transformable ( UInt $src_type, UInt $dest_type --> Bool )

  • UInt $src_type; Source type.

  • UInt $dest_type; Target type.