A rule can contain alternative blocks called subrules (as allowed in Extended BNF Notation: EBNF). A subrule is like a rule that lacks a name and is enclosed in parentheses. Subrules can have one or more alternatives inside the parentheses. Subrules cannot define attributes with locals and ...
Parsing: the sequence of tokens is converted into a syntax tree. In Ox, the parser is derived from a grammar in EBNF form. It receives a list of tokens and outputs an arbitrary parse tree. Semantic analysis: the parse tree is scanned for semantic errors (e.g. invalid variable names, in...