This section provides an extended introduction to syntax/parse as a series of worked examples.
1.2.1 Phases and Reusable Syntax Classes
1.2.2 Optional Keyword Arguments
1.2.3 Variants with Uniform Meanings
1.2.4 Variants with Varied Meanings
1.2.4.1 Syntactic Normalization
1.2.4.2 Non-syntax-valued Attributes
1.2.5 More Keyword Arguments
1.2.6 Contracts on Macro Sub-expressions