# clean-compiler

The [Clean][clean] compiler.

The official Clean compiler can be found at
[https://svn.cs.ru.nl/repos/clean-compiler/][cocl].
This is a fork to implement experimental new features.

---

## Contents

1\. [Syntactic sugar](#1-syntactic-sugar)  
1.1. [Lambda-case](#11-lambda-case)  
2\. [Syntax changes](#2-syntax-changes)  
2.1. [Use of the `module` keyword](#21-use-of-the-module-keyword)  

---

## 1. Syntactic sugar

### 1.1. Lambda-case

Similar to [GHC's LambdaCase][ghclambdacase], this is a sugar for lambda
expressions where the argument is only used in a `case .. of` expression. For
example,

```clean
\case of
	0 = "zero"
	1 = "one"
	_ = "many"
```

is transformed to

```clean
\x -> case x of
	0 = "zero"
	1 = "one"
	_ = "many"
```

where `x` is a fresh variable.

The extension to the grammar:

```
LambdaAbstr = ...
            | \case of {CaseAltDef}+
```

## 2. Syntax changes

### 2.1. Use of the `module` keyword

The `module` keyword is only a keyword on the topmost level. This allows for
using it as a record field, for example:

```clean
:: MyType = { module :: Int }
```

However, it is not allowed to define a function named `module`.

[clean]: http://clean.cs.ru.nl
[cocl]: https://svn.cs.ru.nl/repos/clean-compiler/
[ghclambdacase]: https://downloads.haskell.org/~ghc/latest/docs/html/users_guide/glasgow_exts.html#lambda-case