nitnelave / hopper

Programming language

GrassHopper

DEPRECATED IN FAVOR OF JUST USING D.

GrassHopper is a programming language that aims to do what C++ does, but better. In other words, we aim to be to C++ what Kotlin is to Java.

Among the objectives of the language:

• Fun to write
• As expressive as C++ (ability to control low-level aspects)
• Less dangerous than C++
• Easier to write meta-programming
• Relatively easy to learn (especially after C++).

Among the non-objectives:

• Conceptually pure/beautiful language We're not trying to make a nice abstract language, but a down-to-earth, practical one that is fun to write.
• Full memory safety We don't want the user to deal with the complexity of Rust's reference-borrowing.
• Retro-compatibility This is a brand-new language, not C++++.

This language is still very much a work in progress. The grammar and list of features is likely to change a lot before it is stable.

Document with the features we would like to include: https://docs.google.com/document/d/1lScKPRK0yW46oty-ZUGUu_H-638nEmz5h-t-KyIqi9w/edit?usp=sharing

If you want to contribute, feel free to contact us! We are in need of developer workforce.

hopper's Issues

Write pretty-printer for the AST

Add support for if/else

Note: if/else is an expression.

Needs:

• Parser
• Pretty-printer
• Type checker (boolean condition)
• Code generation (see IR phi nodes)

Switch from boost::program_options to gflags

Add support for string literals

This includes lexing them, making an AST node, pretty-printing them, making a builtin type, and (possibly) generating IR.

Add support for simple function calls

Needs:

• Parser
• Pretty printing
• Type checking (return type, arguments)
• code generation

Add support for while loops

Needs:

• Parser
• Pretty-printer
• Type checker (boolean condition)
• Code generation (see IR phi nodes)

Add support for If-expression

We would like to add support for expressions of the like:

val a = if (cond) value else other_value;

Setup travis

Already registered, need a .travis.yml

Create the AST

Add support for floating point numbers

Needs:

• Lexing
• Parsing (AST node)
• Builtin type
• Pretty printer
• Code generation

Write lexer

Add support for declaring main entry point of program

Right now we can't decide which function is going to be the main entry point, we should:

• decide a name of the entry point (main is the most common one I think),
• assign in the IRBuilder the right entry point,
• raise an alert if the entry point is not present ?

Add support for variable assignment

Needs:

• parsing
• type checker
• code generation (see IR Static Single Assignment)

Add support for C Foreign Function Interface

This will allow printing, among other things.

Needs:

• Parsing (extern "C"?)
• Type checker (only primitives or pointer to, for now)
• Code generation (should be simple)

Add constness check

Add a visitor to make sure that "val" variables are not mutated in the context of the function/program.

Add support for pointers

Pointers are non-null, and can only (for now) be obtain by taking a reference.

Needs:

• Parser (referencing, dereferencing)
• Type checker
• Code generation

Write parser

Setup codecov

https://codecov.io/gh/nitnelave/hopper

Add support for macros

This is a major enhancement, and will come later in the development process.

Needs:

• Lexing
• Parsing
• Name resolution
• Macro expansion (recursive)

Add function overload resolution

The rules should be relatively similar to the C++ ones (ideally, simpler), with no implicit construction.

The allowed implicit conversions are:

• pointer to child -> pointer to base
• small int -> bit int
• small float -> big float
• int -> float

And that's it for now.