= Dfinity Haskell Compiler =

DHC is a Haskell compiler that produces WebAssembly.

It accepts only a tiny subset of the language.

== Live demo ==

https://dhc.dfinity.org

== Installation / Dependencies ==

Run `nix build`.

== Usage / Examples ==

The `dhc` program takes Haskell source on standard input and compiles it to
WebAssembly on standard output. Two IO functions are defined:

------------------------------------------------------------------------------
putStr :: String -> IO ()
putInt :: Int -> IO ()  -- `Int` means 64-bit integer.
------------------------------------------------------------------------------

which respectively call WebAssembly imports:

------------------------------------------------------------------------------
system.putStr (ptr : i32, len : i32)
system.putInt (lo : i32, hi : i32)
------------------------------------------------------------------------------

In `system.putInt`, we split the integer into 32-bit halves to make life easier
for JavaScript.

The `rundhc` tool can interpret the output of `dhc`. It expects the input
WebAssembly binary to export a function named `main` that takes no arguments
and returns no arguments.

For example:

------------------------------------------------------------------------------
$ echo 'public(main) main=putStr"Hello, World!\n"' | ./dhc | ./rundhc
Hello, World!
------------------------------------------------------------------------------

== License ==

http://dfinity.network[*(C) 2017 DFINITY STIFTUNG*].

All code and designs are open sourced under GPL V3.

image::https://user-images.githubusercontent.com/6457089/32753794-10f4cbc2-c883-11e7-8dcf-ff8088b38f9f.png[dfinity logo]