fennel-ls/TODO.md

Wishlist of features

([X] = complete, [ ] = planned)

My current goal is to work on completions a little bit more.

• create a release

refactor brainstorm:

• get rid of bytes stuff and use "stack" everywhere

• search caching

• search depth limit / stop recursion

• search into calls

• entry point measurement for reference search

• arg return count

  • i guess searching into calls could do this?

• diagnostic code actions

Here is my feature wishlist. I don't expect to ever get all of this done, but these are the sort of enhancements I am thinking about.

• Able to connect to a client
• Support for UTF-8 characters that aren't just plain ASCII. (especially λ) (perhaps just tell the IDE that I want to communicate with utf-8 offsets)
• People have tried fennel-ls in:
  • Neovim (This project isn't a neovim plugin, but there are instructions on how to inform neovim of the fennel-ls binary once you build it.)
  • emacs
  • helix
  • vscode (publish an extension)
  • vim+coc (publish a node thingy)
• Go-to-definition:
  • literal table constructor
  • table destructuring
  • multisyms
  • . special form (when called with constants)
  • do and let special form
  • require and cross-module definition lookups
  • goes to a.method on (: a :method) when triggered at :method
  • expanded macros (a little bit)
  • table mutation via fn special: (fn obj.new-field [])
  • macro calls / which macros are in scope
  • setmetatable
  • can search through function arguments / function calls / method calls
  • local/table mutation via set/tset
  • .lua files (antifennel decompiler)
  • mutation on aliased tables (difficult)
• Completion Suggestions
  • from globals
  • from current scope
  • from macros (only on first form in a list)
  • from specials (only on first form in a list)
  • "dot completion" for table fields
  • [1/2] dot completion is aware of a stdlib
  • actually compliant rules about lexical scope (only see things declared before, not after)
  • show docs/icons on each suggestion
  • "dot completion" for metatable __index fields
  • (. obj : string completions
  • (: "foo" : string completions
  • (require : module completions
  • from anywhere else that I'm forgetting right now
  • snippets? maybe more?
• Reports compiler errors
  • Report more than one error per top-level form
• Reports linting issues
  • Unused locals
  • Unknown fields of modules
  • Discarding results from pcall/xpcall/other functions
  • [.] unpack or values into a special
  • do/values with only one inner form
  • redundant do as the last/only item in a form that accepts a "body"
  • values/unpack in a non tail position
  • numbers and strings in a non tail position
  • deprecated specials/macros
  • var forms that could be local
  • Arity checking
    • Too many args (assuming there is no ... argument)
    • Too few args (assuming the last argument is statically countable, and also account for ?optional arguments)
    • I need to also make it work for built-in functions
    • warn if an optional arg is present, but no call ever passes the arg
  • Code that matches the shape of accumulate or icollect or collect?? or other macros??
  • Dead code (I'm not sure what sort of things cause dead code)
  • Unused fields (difficult)
  • unification in a match pattern (difficult)
  • unused values in λ (difficult)
  • Brainstorm more linting patterns (I spent a couple minutes brainstorming these ideas, other ideas are welcome of course)
  • Type Checking
• Hover over a symbol for documentation
• Signature help
  • respond to signature help queries
  • hide or grey out the self in an a:b multisym call
• Go-to-references
  • lexical scope in the same file
  • function names work properly and are counted once
  • fields
  • go to references of fields when tables are aliased
  • global search across other files
• Options / Configuration
  • Configure over LSP
  • Configure with some sort of per-project config file
  • Configure with environment variables I guess??
  • fennel/lua path
  • lua version
  • allowed global list
  • enable/disable various linters
• rename
  • local symbols
  • module fields (may affect code behavior, may modify other files)
  • arbitrary fields (may affect code behavior, may modify other files)
• formatting with fnlfmt
• Type annotations? Global type inference?

fn-arg-nil: Function arguments are assumed to be nil in a function body, until there's a type system to give more information.

hashfn: Hash functions currently don't work well.

refs-dedup: