doc/guide/src/Identifier.adoc

   1 Identifier
   2 ==========
   3
   4 In <:StandardML:Standard ML>, there are syntactically two kinds of
   5 identifiers.
   6
   7 * Alphanumeric: starts with a letter or prime (`'`) and is followed by letters, digits, primes and underbars (`_`).
   8 +
   9 Examples: `abc`, `ABC123`, `Abc_123`, `'a`.
  10
  11 * Symbolic: a sequence of the following
  12 +
  13 ----
  14  ! % & $ # + - / : < = > ? @ | ~ ` ^ | *
  15 ----
  16 +
  17 Examples: `+=`, `<=`, `>>`, `$`.
  18
  19 With the exception of `=`, reserved words can not be identifiers.
  20
  21 There are a number of different classes of identifiers, some of which
  22 have additional syntactic rules.
  23
  24 * Identifiers not starting with a prime.
  25 ** value identifier (includes variables and constructors)
  26 ** type constructor
  27 ** structure identifier
  28 ** signature identifier
  29 ** functor identifier
  30 * Identifiers starting with a prime.
  31 ** type variable
  32 * Identifiers not starting with a prime and numeric labels (`1`, `2`, ...).
  33 ** record label