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

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

The `Script_Extensions` property (`scx`) records the scripts a codepoint is commonly used with, which for shared characters is more than one (see [UAX #24](https://www.unicode.org/reports/tr24/)). U+0640 ARABIC TATWEEL, for example, has `Script` value `:common` but is used with Arabic, Syriac, Mandaic and others; its `Script_Extensions` value names each of them. Matching on `Script_Extensions` rather than `Script` is required for [UTS #18](https://www.unicode.org/reports/tr18/) RL1.2 conformance.

The property is set-valued: each codepoint maps to a *set* of scripts. This module inverts that mapping so a codepoint appears under every script in its set, which is both the shape the other property modules use and the form queries actually take — `script_extensions(:latin)` answers "which codepoints have Latin in their set?".

Two consequences of UAX #24 are worth knowing:

* A codepoint absent from the `Script_Extensions` data takes its `Script` value, so this module returns a superset of `Unicode.Script` for most scripts rather than only the explicitly listed characters.

* For a codepoint that *is* listed, the listed set replaces its `Script` value. U+00B7 MIDDLE DOT has `Script` value `:common`, but `:common` is not in its `Script_Extensions` set, so it is absent from `script_extensions(:common)`.

The primary API is `script_extensions/1` which returns the scripts of a codepoint, or of a string.

# `aliases`

Returns a map of aliases for Unicode script extensions.

The `Script_Extensions` property takes `Script` property values, so the `Script` aliases apply
here unchanged — `"latn"` and `"latin"` both resolve to `:latin`.

### Returns

* A map where the alias string is the key and the script name is the value.

### Examples

    iex> Unicode.ScriptExtensions.aliases() |> Map.get("latn")
    :latin

# `count`

Returns the count of the codepoints having a given script in their `Script_Extensions` set.

Aliases are resolved by this function.

### Arguments

* `script` is any script name or alias, as an atom or string.

### Returns

* A non-negative integer count of the codepoints with the script extension.

* `:error` if the script is not known.

### Examples

    iex> Unicode.ScriptExtensions.count(:latin)
    1720

    iex> Unicode.ScriptExtensions.count(:bopomofo)
    122

# `fetch`

Returns the Unicode codepoint ranges for a given script extension.

Aliases are resolved by this function.

### Arguments

* `script` is any script 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 script is not known.

### Examples

    iex> Unicode.ScriptExtensions.fetch(:latin) |> elem(0)
    :ok

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

# `get`

Returns the Unicode codepoint ranges for a given script extension.

Aliases are resolved by this function.

### Arguments

* `script` is any script name or alias, as an atom or string.

### Returns

* A list of codepoint ranges as 2-tuples.

* `nil` if the script is not known.

### Examples

    iex> Unicode.ScriptExtensions.get("latn") |> is_list()
    true

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

# `known_script_extensions`

Returns a list of known Unicode script names for the `Script_Extensions` property.

### Returns

* A list of atom script names.

### Examples

    iex> :latin in Unicode.ScriptExtensions.known_script_extensions()
    true

# `script_extensions`

Returns the map of Unicode script extensions.

### Returns

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

### Examples

    iex> Unicode.ScriptExtensions.script_extensions() |> Map.fetch!(:latin) |> is_list()
    true

# `script_extensions`

Returns the `Script_Extensions` set 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, the list of script name atoms in its `Script_Extensions` set, sorted. An
  unassigned codepoint returns `[:unknown]`.

* For a binary, the sorted union of the sets of the codepoints in the binary.

### Examples

    iex> Unicode.ScriptExtensions.script_extensions(?A)
    [:latin]

    iex> Unicode.ScriptExtensions.script_extensions(0x02C7)
    [:bopomofo, :latin]

    iex> Unicode.ScriptExtensions.script_extensions("Aά")
    [:greek, :latin]

---

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