This is the Vala port of Berp Ported by Chris Daley chebizarro@gmail.com 2015

A flexible cross-language parser generator with support for languages without explicit tokenization rules (like Gherkin).

Features:

• generates parser for it's own grammar (the "hello world" for parser generators), see Berp Grammar
• does not generate a lexer/tokenizer, so ideal for languages where tokenization is easy or anyway not really possible
• simple, BNF-like grammar definition
• supports multiple target languages (currently C# and Ruby) with the same grammar (the language generation is specified in template files)
• allows building AST, with AST-building hooks
• supports streamed token reading (tokens can be kept attached to the input stream to avoid unnecessary data transfer and object creation)
• supports context-sensitive tokens, also possible to change the tokenization rules during parsing (e.g. when a #language: no is encountered)
• supports a special "other" token, that matches to the "anything-else" case, when there is no better match
• support for recursive grammar rules is limited (it parses them up to a certain level only)
• simple, look-ahead rules can be specified
• rules can be marked as production rules to be represented in AST
• allows capturing ignored content tokens (e.g. comments)

Samples:

• Berp Grammar
• Gherkin Grammar

State: alpha

TODO:

• improve error handling and error reporting
• keep and use original rule position (to support repeating sub-rules within the same rule)
• separating token scanner and token matcher for C# generation
• skip generating labels for non-production rules
• cleanup dependency injection (AST builder, token matcher, ...)
• report error lines for grammar parsing errors
• support recursive grammar rules