fennel-ls/TODO.md

Wishlist of features

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

              code unit count (not to be confused with code points)

code point # |utf8 |utf16| offset 000000 - 00007F | 1 | 1 | 0 000080 - 0007FF | 2 | 1 | -1 000800 - 00FFFF | 3 | 1 | -2 010000 - 10FFFF | 4 | 2 | -2

utf8 chart 000000 - 00007F 0xxxxxxx 000080 - 0007FF 110xxxxx 10xxxxxx 000800 - 00FFFF 1110xxxx 10xxxxxx 10xxxxxx 010000 - 10FFFF 11110xxx 10xxxxxx 10xxxxxx 10xxxxxx My current goal is to work on completions a little bit more.

• Fix crash-files.test2

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)
• Settings to configure lua / fennel path, allowed globals, etc
• Supporting builds for anything other than arch linux
• Testing/support/instructions for any clients: (LSP is supposed to be editor-agnostic, but that's only if you're able to actually follow the spec, and I'm not sure that fennel-ls is compliant)
  • 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
  • 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"
  • 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)
  • 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
  • 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?