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https://github.com/irori/hs2lazy

Haskell -> Lazy K translator.
https://github.com/irori/hs2lazy

Last synced: 23 days ago
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Haskell -> Lazy K translator.

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hs2lazy -- Haskell to Lazy K compiler
=====================================

## What is this?

This is a translator from a subset of Haskell to [Lazy K](http://homepages.cwi.nl/~tromp/cl/lazy-k.html).

## How to compile

You can build hs2lazy with GHC by following command:

ghc -o hs2lazy --make Main.hs

## How to use

hs2lazy [source files]

If multiple source files are given, they are concatenated in the order specified. Output Lazy K code is written to standard output.
Prelude module is not automatically loaded. So, you may specify examples/hs2lazy-prelude.hs first, like following:

hs2lazy examples/hs2lazy-prelude.hs foo.hs >foo.lazy

## How to write source code

In Lazy K, input and output streams are represented as infinite lists of numbers (256 represents EOF). Hs2lazy programs handle I/O in similar way.

In Haskell, type of `main` function is `IO ()`. But in hs2lazy, that is:

main :: Stream -> Stream

The Stream type is defined in hs2lazy-prelude.hs as

data Stream = Stream Char Stream

The input is a infinite stream of characters. For example:

Stream 'f' $ Stream 'o' $ Stream 'o' $ Stream eof $ Stream eof ...

`eof` is defined as `(chr 256)`.

Streams can be converted to/from strings by `fromStream` and `toStream` defined in hs2lazy-prelude.hs. For example, following program reverses the input character-by-character.

main = toStream . reverse . fromStream

Or simply,

main = interact reverse

`interact` converts a String-to-String function to a Stream-to-Stream function.

## License

Type.hs is based on [Typing Haskell in Haskell](http://web.cecs.pdx.edu/~mpj/thih/). See Lisence.thih for the license of it.