Enum Unicode 

pub enum Unicode {}

A Unicode Standard Annex #31 profile (with LOW LINE, ZWJ, and ZWNJ removed).

Character Set

This profile uses the unicode-ident crate.

• Start => any character that passes is_xid_start(c) (except LOW LINE, ZWJ, and ZWNJ).
• Continue => any character that passes is_xid_continue(c) (except LOW LINE, ZWJ, and ZWNJ).

About Low Line Omission

It’s confusing if the character profile contains a delimiter.

Instead, if you want an identifier that includes the low-line character, you should select such an identifier (from the presets, or by including it as a delimiter in a custom identifier).

We still “include” the character, we just want it to be treated specially.

About ZWJ+ZWNJ Omissions

The zero-width joiner characters (U+200D and U+200C) have special usage within this profile, as detailed in the above specification. However, it requires extra processing to use them properly - we simply omit them.

If you wish to support these extended use-cases, you can create a custom profile which allows these characters (simply by not disallowing them, just call into unicode-ident functions). But you’ll have to implement additional validation on top of the identifiers you form (perhaps as a newtype).

In my reading of this standard, the zero-width characters are just not worth the headache. I really strongly recommend against their inclusion.

Trait Implementations

impl CharProfile for Unicode

impl Profile for Unicode

const APPEND_CLOSED: AppendClosed = AppendClosed::Fragment

Whether or not a fragment containing characters in this profile are append-closed.

type BaseProfile = Unicode

The underlying profile that this profile is based on.

type Segmentation = Grapheme

The segmentation strategy that this profile uses.

fn is_ident_start(c: char) -> bool

Whether or not the provided character can appear at the absolute start of an identifier.

fn is_chunk_start(c: char) -> bool

Whether or not the provided character can appear at the start of a new chunk (e.g. right after a delimiter).

fn in_profile(c: char) -> bool

Whether or not the provided character can appear at any point in a chunk.

fn is_chunk_continue(c: char) -> bool

Whether or not the provided character is valid at any position after the first character of a chunk (a run of non-delimiter characters).

impl SubsetOf<Unicode> for Strict

Proof: Strict is a subset of the Unicode profile (strict has more restrictions).

impl SubsetOf<Unicode> for Ascii

Proof: ASCII is an obvious subset of Unicode.

impl SubsetOf<Unicode> for Unicode

Proof: It’s always safe to implement this against yourself.