nballerina

This will eventually be a Ballerina compiler, written in Ballerina, which uses LLVM to generate native executables.

The compiler is divided into the following Ballerina packages:

• driver - this coordinates the other packages to perform the compilation
• bir - this defines a Ballerina-specific intermediate representation (BIR) of Ballerina programs
• front - this turns Ballerina source code into BIR
• llvm - this generates LLVM IR from BIR
• types - this defines a normalized representation of Ballerina's types, and associated operations such as subtype testing and intersection

The dependencies are as follows:

• bir depends on types (BIR is typed using the normalized types provided by types)
• llvm depends on bir and types (but not front)
• front depends on bir and types (but not `llvm)
• driver depends on everything

So far, the only implemented functionality relates to types:

• the front module can parse a module containing Ballerina type definitions in this subset of Ballerina syntax;

• the front module can use the types module to build a normalized representation;

• the types module can determine whether one type is a semantic subtype of another (more information on this);

• the driver module allows you to play with this: it will print out the subtype relationships between all named types in a Ballerina module; the directory driver/tests/data has some examples you can try out.