poise

The Poise programming language.

This is a rewrite of grace because grace was a mess (the name is a synonym).

Issues/Things on the Long Finger

• Parse argv properly, main function/file in general
• Testing
  • Test individual important functions
  • Fuzzing
• Think about object -> bool conversion
• Generally improve compiler errors and stop it from spitting out nonsense after one error, eg lambda capture errors
• Use hashes instead of strings in runtime
  • Function names, namespace lookups, etc
  • And maybe also in the compiler when we need to optimise that
• Package manager type thingy
  • Type checker for those optional type hints
  • Project manager/runner
  • Dependency stuff (cloning a Git repo, structure convention, precompiled bytecode)
• Compiler warnings
• Optimisation
• getCodeAtLine() for imported files
• Store number of lines in a file when it's loaded so getNumLines isn't so expensive
• Try and remove static data structures
• Full UFCS + Any type annotation?
  • In general, I think I prefer the idea of having an Any type annotation as opposed to full UFCS.
  • However, adding an extension function to Any gets complicated.
  • Currently, each type has a list of its extension functions. Keeping this system, an extension function on Any would have to be added to all current and future types when compiled
  • We'd have to reverse this association, so each function knows which types it extends, but this is tedious to look up at runtime
  • So maybe the current system is ok? A PoiseFunction instance in a Value is basically a shared pointer, so it's not too crazy
• Namespace qualified calls are a little messy
• DualIndexSet is great but let's optimise it a bit
  • Done, just make a wrapper around a boost set!
• Use of more efficient sets/maps, and use these instead of vectors for things that are often looked up with find_if

Feature Roadmap

• Pop unused expression/return results
• Create values by calling type as a constructor, eg Int(), Float(1.0)
• Implement types as first class objects - see below
  • Done except for user defined classes when we get to that...
• Assertion failure in formatting compiler error output for missing semicolons
• Expressions with primitives
  • Short-circuiting
• Variables
• Functions
  • Declaration
  • Calling
  • Returning
  • Lambda
• Assignment statements
• Error handling
  • When we do constants, handle a constant value for construction Exceptions
  • Print only the first few call stack entries on error
  • throw statement
• If statements
• While loops
• Native functions
  • These are done, just need to actually implement everything else
  • Disallow calling a native function outside std files
• Imports + Namespaces
  • Wildcards
  • Multiple imports in {}
  • Back a folder
• Namespace aliases
• Export functions
• Dot functions
  • For imported functions...
    • Put the namespace stuff into its own class
    • Functions need to know what namespace they're in
    • Types know what extension functions they have
    • Check if that function's namespace has been imported to the namespace of the current function in the Vm
  • Two functions with the same name in a different namespace will override each-other
  • Add an ability for "static" extension methods - this is how we will do struct constructors (Foo.new())
• Builtin objects
  • Use types::Type instead of Value::TypeInternal for type()
  • Iterable collections
    • Tidy up access modifiers
    • Lists
    • Ranges
      • Can't change the internal state of the range so that you can iterate over it many times, or concurrently
    • Tuple
    • Dicts
    • Sets
    • Index operator
  • Special constructors for the above
  • Binary ops for the above
  • Could we do some kind of rust/c# linq/ranges style lazy evaluation...
  • Option and Result types?
    • No need, try assignments work like Results, everything is an option because anything can be none - implement is_none() and is_some() on Any
• For loops
  • Make sure everything's working fine for more collections we add
• Zig style try assignment
  • Could this be like a unary operator as opposed to only valid on assignment, so foo(try bar()) is valid?
• Parameter packing and unpacking
  • Expand unpacking into collections
    • Remember this when we add Dicts and Sets...
  • Unpack a collection
  • Multiple assignments on one line (a, b = b, a) or assigning an unpack (a, b = ...collection)
    • Partial unpacking - var (a, b, ...rest) = ...collection unpacks the first two items into a and b and the remaining into rest.
    • How to parse var a, b, c = try ...expr?
      • Doesn't really work, because exceptions get a bit strange. This implementation is sorted now.
    • How badly do we want multiple assignments? Right now it works for variable declarations, but not for...
      • Reassigning variables
      • Assigning indexing etc
      • It would also imply the ability to return multiple values from a function
      • I'm just hesitant because of how annoying it is to compile LOL but maybe there's a better way to handle assignments in general in the compiler
  • Friendship ended with PoisePack, PoiseList is my best friend now
  • A "pack" will not be a unique type, and you will simply be able to unpack any collection
• Construct Type instance, Type ident
• Union type annotation so that we can implement functions on multiple collections
  • Have type aliases, eg type OrderedCollection = List|Range
  • You should be able to export and import these
  • Maybe leave this until we do user defined classes, and we can come up with a nice generic way to handle it, since we'll have to work off of identifiers rather than builtin type keywords.
• Break/continue statements
• Structs
  • Member variable access
  • Extension function access
  • Need to generate PoiseType instances for these, and hook them into everything else - we may need to do some type of verification step on extension methods when the vm starts running
  • Need a class for instances
  • typeof for structs and struct instances such that for struct Foo {}, typeof(Foo) == Type and typeof(Foo{}) == Foo
• Objects in constant expressions to allow for object default struct values
  • This shouldn't be complicated, there's really no reason not to allow it, we just can't call functions
  • Need a deep clone mechanism for objects so that structs instantiated with default values get deep copies of objects
• GC for cycles
  • Investigate horrible performance with Clang with cycles.poise (n=10000)
  • Ah, so using unordered_set instead of vector solved this
  • But, I bet performance is better for small amounts of objects - test this, and decide which should we optimise for? Is swapping between the two depending on the load viable?
  • Optimise the sweep frequency - perhaps update the graph constantly with allocations/deallocations?
• Binary/Hex literals
• Digit separators
• Constants
  • Constant expressions
  • Type checked and folded into bytecode
• Crashes in compiler on EOF token
• Pattern matching
• Ifs as expressions
  • Do we want this, or some kind of ternary mechanism?
• Identifier loading in runtime can be simplified now that strings are interned
• Single expression lambdas
  • But, perhaps we could do || => <expr> and then also have single line functions like that too (func foo() => <expr>)
  • Figure out how to compile this as a statement rather than an expression - need to return null in case of a print or loop statement etc.
• Type hints
  • Expand to include user defined classes when we do these
    • Could we compile time check for the existence of the class? Is there a situation where you'd need to define a function that takes a class, before defining that class?
    • Yes, for cyclic dependant files.
  • Allow >= 2 generic types for dictionaries, tuples etc when we do those
• CL arg parsing
• Standard Library
  • Precompile as bytecode files
• Finish iterators for DualIndexSet

Iterable Inheritance Diagram

Object
 |
 |   _______________________ Iterable
 |__|_______|__________         |
 |  |   |   |   |______|____ Hashable
 |  |   |   |   |  |   | |
 List   Range   Dict   Set