BNF

<attribute> ::= <expression> "." <identifier>
<call>      ::= <expression> "(" <arguments> ")"
              | <expression> ":" <simple-arguments>
<operator>  ::= <expression> <identifier> <expression>
<ellipsis>  ::= <expression> /[.]{2,}/ <expression>
<square-brackets> ::= "[" <arguments> "]"
<curly-brackets>  ::= "{" <block> "}"
changed April 4, 2009