For now, this reference is a best-effort document. We strive for validity and completeness, but are not yet there. In the future, the docs and lang teams will work together to figure out how best to do this. Until then, this is a best-effort attempt. If you find something wrong or missing, file an issue or send in a pull request.

Identifiers

Lexer:
IDENTIFIER_OR_KEYWORD :
      [a-z A-Z] [a-z A-Z 0-9 _]*
   | _ [a-z A-Z 0-9 _]+

IDENTIFIER :
IDENTIFIER_OR_KEYWORD Except a strict or reserved keyword

An identifier is any nonempty ASCII string of the following form:

Either

  • The first character is a letter.
  • The remaining characters are alphanumeric or _.

Or

  • The first character is _.
  • The identifier is more than one character. _ alone is not an identifier.
  • The remaining characters are alphanumeric or _.