fluent.syntax 0.14.0

This release of fluent.syntax brings support for version 0.9 of the Fluent
Syntax spec. The API remains unchanged. Files written in valid Syntax 0.8 may
parse differently in this release. See the compatibility note below. Consult
the full Syntax 0.9 changelog for details.

• Flatten complex reference expressions.

  Reference expressions which may take complex forms, such as a reference
  to a message's attribute, or a parameterized reference to an attribute of
  a term, are now stored in a simplified manner. Instead of nesting
  multiple expression nodes (e.g. CallExpression of an
  AttributeExpression of a TermReference), all information is available
  directly in the reference expression.

  This change affects the following AST nodes:

  • MessageReference now has an optional attribute field,
  • FunctionReference now has a required arguments field,
  • TermReference now has an optional attribute field and an optional
    arguments field.

• Remove VariantLists.

  The VariantLists and the VariantExpression syntax and AST nodes were
  deprecated in Syntax 0.9 and have now been removed.

• Rename StringLiteral.raw to value.

  StringLiteral.value contains the exact contents of the string literal,
  character-for-character. Escape sequences are stored verbatim without
  processing. A new method, Literal.parse, can be used to process the raw
  value of the literal into an unescaped form.

• Rename args to arguments.

  The args field of MessageReference, TermReference,
  FunctionReference, and Annotation has been renamed to arguments.

Backward-incompatible changes:

• VariantLists are no longer valid syntax. A syntax error is reported
  when a VariantList or a VariantExpression is found in the parsed file