# `Unicode.DecompositionType`
[🔗](https://github.com/elixir-unicode/unicode/blob/v2.2.0/lib/unicode/property/decomposition_type.ex#L1)

Functions to introspect the Unicode `Decomposition_Type` property for binaries (Strings) and codepoints.

The `Decomposition_Type` property classifies the kind of decomposition mapping a codepoint has, for example `:canonical`, `:compat`, `:font`, `:circle` or `:nobreak`. Codepoints with no decomposition mapping have the value `:none`.

The primary API is `decomposition_type/1` which returns the decomposition type of a codepoint, or the list of decomposition types of a string.

# `aliases`

Returns a map of aliases for Unicode decomposition types.

### Returns

* A map where the alias string is the key and the decomposition type is the value.

### Examples

    iex> Unicode.DecompositionType.aliases() |> Map.get("can")
    :canonical

# `count`

Returns the count of the codepoints with a given decomposition type.

Aliases are resolved by this function.

### Arguments

* `decomposition_type` is any decomposition type name or alias, as an atom or string.

### Returns

* A non-negative integer count of the codepoints with the decomposition type.

* `:error` if the decomposition type is not known.

### Examples

    iex> is_integer(Unicode.DecompositionType.count(:canonical))
    true

# `decomposition_type`

Returns the decomposition type of the given binary or codepoint.

### Arguments

* `string_or_codepoint` is either a binary (String) or a codepoint in the range `0..0x10FFFF`.

### Returns

* For a codepoint, a single decomposition type atom is returned. Codepoints with no decomposition mapping return `:none`.

* For a binary, a list of the distinct decomposition types of the codepoints in the binary is returned.

### Examples

    iex> Unicode.DecompositionType.decomposition_type(0x00A0)
    :nobreak

    iex> Unicode.DecompositionType.decomposition_type(?A)
    :none

# `decomposition_types`

Returns the map of Unicode decomposition types.

### Returns

* A map where the decomposition type is the key and a list of codepoint ranges as 2-tuples is the value.

### Examples

    iex> :canonical in Map.keys(Unicode.DecompositionType.decomposition_types())
    true

# `fetch`

Returns the Unicode codepoint ranges for a given decomposition type.

Aliases are resolved by this function.

### Arguments

* `decomposition_type` is any decomposition type name or alias, as an atom or string.

### Returns

* `{:ok, range_list}` where `range_list` is a list of codepoint ranges as 2-tuples.

* `:error` if the decomposition type is not known.

### Examples

    iex> Unicode.DecompositionType.fetch(:canonical) |> elem(0)
    :ok

    iex> Unicode.DecompositionType.fetch(:invalid)
    :error

# `get`

Returns the Unicode codepoint ranges for a given decomposition type.

Aliases are resolved by this function.

### Arguments

* `decomposition_type` is any decomposition type name or alias, as an atom or string.

### Returns

* A list of codepoint ranges as 2-tuples.

* `nil` if the decomposition type is not known.

### Examples

    iex> Unicode.DecompositionType.get(:invalid)
    nil

# `known_decomposition_types`

Returns a list of known Unicode decomposition type names.

### Returns

* A list of atom decomposition type names.

### Examples

    iex> :compat in Unicode.DecompositionType.known_decomposition_types()
    true

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*Consult [api-reference.md](api-reference.md) for complete listing*