TODO

[glaebhoerl]

• Docs
• Tests

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Features

• Implement functions
  • Parsing
  • Pretty-printing
  • Name resolution
  • Typechecking
  • IR
  • LLVM
• Need to enforce that functions actually return something!! :(
• Implement a string type
• Better error reporting
  • Source location tracking
    • Token
    • AST
    • Name.Error
    • Type.Error
  • <?> or whatever in AST parser
  • Store source Text in metadata?
  • instance Render Token.Error
  • instance Render AST..Error
  • instance Render Name.Error
  • instance Render Type.Error
  • Anything else....?
• Pretty printing of AST
• More analyses / transformations in IR?

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Odds and ends

• Re-add validation for Type
• Validation of IR should validate Functions
• Make validation failures print the thing that failed to validate
• Bikeshedding and other cleanup of Pretty
• instance Render IR.Function
• nicer pretty-printing of types
• AST could store full Expressions (or other nodes) instead of just names in some places for finer-grained location metadata

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Bugs

• Less hacky newline handling
• Properly handle exceptions in Main
• Fix - parsing ambiguity (unary vs. binary vs. literal)
• Fix Tardis-related laziness hacks in IR
• Fix dead-code-related bugs in IR generation
• Refactor handling of precedence in AST (and fix for &&, ||)?
• Improve handling of operations in LLVM to avoid UB on overflow/div-by-zero/etc.
• function isBuzz(number: Int) returns isBuzz validation error
• IR validation error due to function w/ if { return x } else { return x } and implicitly inserted unit return
• Name doesn't record metadata/location for function arguments/returns (and maybe others)

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Facultative

• Implement break
• anonymous scopes
• unify say() and write()? ask() for strings?
• make comparison operators polymorphic?
• Either -> Validation?
• Bool literals
• Unit in AST
• function types in syntax, C-level HOFs?
• type annotations on lets
• type annotations in expressions
• add more pretty-printing styles (e.g. name-based, scope-based, type-based semantic highlighting); allow selecting w/ command-line flag?
• add continue

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Refactor

• Update to GHC 8.6, LLVM 7
• enable StrictData?
• check assignments in Name, get rid of NameWith? would invalidate Name.validate
• rename repo
• use unused instead of _ <-
• make use of modifyM variants directly returning the modified state, where appropriate
• text-path-utf8?
• safe-exceptions?
• organize Token
• try DeriveAny again?
• can we use DerivingVia? or QuantifiedConstraints?
• BlockArguments!!
• our own Loc type?
• make the error-type in Main be a Doc rather than Text?
• some kind of multiplatey abstraction?
• add a method in Render to customize how lists of the type are rendered, get rid of the flexible list instances?
  • instance Render a => Render (Maybe a)?
• style consistency: where always trailing
• style: always require newline after ->/=...?
• do something about all the warnings
• keep a stack of metadata instead of a scalar for better robustness?
• factor out a MonadMetadata or something?
• generalize the parser itself over arbitrary Monoid metadata?
• collapse LLVM.FirstState and SecondState, with just the instances differing?
• DisambiguateRecordFields?
• StateT -> ReaderT
• explore https://github.com/lamdu/syntax-tree ?

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FUTURE

• IRBuilder?
• SSA?
• Change IR to graph-based Thorin-style
• Expression language
• Bidirectional typechecking
• Unification
• Nonlocal breaks, breaks returning values
• Struct types
• Sum types, simple switches
• Stack closures
• Stack references (lifetime checking?)
• Arrays, stack slices
• Heap allocation, reference counting, heap-allocated strings, arrays, closures