Identifier

Syntax
Identifier: [_a-zA-Z][_0-9a-zA-Z]*

Note: Unicode identifier is allowed but discouraged.

A valid identifier is a sequence of characters that satisfies the following conditions:

• The sequence must not start with '0'..'9'.
• The sequence must not contains whitespace characters, namely ' ', '\r', '\n', '\t' .
• The sequence must not contains any ascii symbols like ?#$@%... .
• Unicode characters may be used. For example, 🐱🐶 is valid identifier.