This directory contains support code for the parser-combinator underlying the syntax code, as well as the code to transform grammar.js to fluent.ebnf. The combination allows for a succinct formulation of the syntax in grammar.js and a readable representation of that in fluent.ebnf.
parser.js is the base parser class, stream.js holds a iterator over the strings to be parsed.
combinators.js holds the actual basic grammar productions and logical combinations of grammar productions.
Both use Success and Failure from result.js to pass success and failure conditions forward.
After the definition of grammar productions, the utilities in mappers.js are used to concat, flatten, and extract the matched data to prepare it for AST generation.
The fluent.ebnf is created by parsing the grammar.js and transpilation to an EBNF file. The babylon JavaScript parser is used to load a Babel AST.
ebnf.js is the top-level entry point used by bin/ebnf.js. It uses the iteration logic from walker.js to go over the Babel AST and to extract the information relevant to the EBNF via the Visitor in visitor.js. The resulting data is then serialiazed to EBNF via serializer.js.