UPDATE: Work on burn is ongoing at rainbow-alex/burn.js.
Burn intends to be a light-weight, general-purpose programming language. Here are some of its properties you're likely to know from existing languages:
- Newlines separate statements. Curly braces are mandatory.
- Block scoping.
- Values have types, variables don't. Values are not implicitely coerced.
- Functions are first-class values and can have free variables (lexical closure).
- Object-oriented programming with multiple inheritance. Classes are first-class values too, and support lexical closure.
- Memory is garbage-collected.
- Concurrency is achieved through fibers.
- It compiles to bytecode at runtime. This bytecode is (to some small degree) self-optimizing.
Of course there's more to Burn than that. Here are some of the twists that really set Burn apart:
Typing
Burn's types are more like mathematical sets than the type systems you are probably familiar with.
Think Venn diagrams rather than family trees.
It has the usual types like Integer or String, but also Positive or Empty.
There are a lot of types in the standard library, but you can create your own as well. Types are first-class values and can be combined and created ad hoc:
let $Real = Integer | Float
let $NonEmptyString = String + not Empty
let $HttpUrl = String.starting_with( "http://" )
let $CustomType = function( $value ) { return <boolean expression> }
Object capabilities
Burn follows an object-capability model.
Capabilities are functions or objects that can do things with side-effects (e.g. read a file or print to stdout).
All capabilities are given to the program entry point (i.e. main), and it is then responsible for passing them to other parts of the program.
This is basically nothing more than language-enforced dependency injection.
- You can, at any time, safely import a library or load a script. It can only have side-effects if and when you give it the required capabilities.
- An untrusted Burn program can be run with reduced capabilities, or by lazily prompting them from the user.
- You can safely embed Burn without cutting off access to third party libraries by simply giving it reduced capabilities.
- Burn programs are probably more likely to be reusable and testable.