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Basic detail suggestions:

• Programming language: [[/languages/Haskell]]
• Main module: Language.Idan
• Package name: language-idan
• License: I’ve been using GPLv3+ until now, but as the code probably won’t reuse anything else and won’t call any GPL library functions, it’s a good chance to use CC0 here. But make sure it’s not a pseudo-not-taking-side CC0, but an anti-law-anti-violence-anti-copyright CC0. Otherwise it will cause harm in the indirect ways BSD, MIT, etc. do

The main focus for the beginning is the parser.

Process idea: lexical analysis -> parsing -> syntax tree -> semantic analysis

Component/module/data ideas:

• Lexemes for emitting by lexer
• Token hierarchy for emitting by parser
• Model components for syntax tree
• Things for semantic analysis? (e.g. linking references and labels of anchors)

Plan idea:

• Tokenize using [[!hackage alex]]
• Parse using [[!hackage parsec]]
• Code the remaining tree traversals (huge case statements)
• The library may have a SAX-like API in which it exposes things in various levels of abstraction/features/model, and on top of that data models that use them (like DOM). There can be an Idan-specific model, and there are 2 more models that are generally useful (think the graph-based file conversion tool): statement block based model, and plain quads model
• Note that “callbacks” don’t just work like in C/C++. Perhaps just building a model is ok, since Haskell is lazy. But if not, use class/type for “templates” the user fills (like letting the user derive a Parser class) or let it be a monad the user supplies (as in model >>= insertStatement)
• Look at existing parsers (e.g. for Turtle, JSON, XML) in Haskell

Notes:

• After reading a bit about using alex and parsec I found [[this|https://ro-che.info/articles/2015-01-02-lexical-analysis]]. Since Idan has all those tricky things like indentation and multi-line strings, the arguments there probably apply. Instead of Alex, I will start by using [[!hackage regex-applicative]] as a lexical analyzer.
• [[!hackage rdf4h]]’s parsers, including a Turtle one, use plain parsec without alex etc.