# haskeme

This compiler translates Scheme source code written with I-Expressions (indented expressions) into S-Expressions (symbolic expressions).

## Usage
Haskeme can read and write files:

    haskeme --input "program.hss" --output "program.ss"

Haskeme can also use `StdIn` and `StdOut`:

    cat "program.hss" | haskeme > "program.ss"

### Options
- `-i` or `--input` to specify input file
- `-o` or `--output` to specify output file

## I-Expressions
I-Expressions are indented expressions and are translated by few simple rules:

- a new line translates to a new S-Expression
- same indentation as the expression above translates to a new S-Expression following the prior one
- more indentation as the expression above translates to a new S-Expression as an argument to the prior one
- less indentation as the expression above, but still more indentation as another expression above translates to a new S-Expression, while the prior and further indented block gets wrapped in extra parentheses (look at the `let`-example)
- S-Expression can be mixed in while staying in a single line (look at the example for mixed expressions)
- full line comments starting with `;` are ignored
- a new line can be prevented from being turned into an S-Expression by prepending it with `:` after the indent (look at the example for prevented expressions)


### Example
- I-Expressions:

    ```racket
    define f
      lambda
        x
        let
            y
              * x x
          if
            > x 0
            + y 1
            : #f
    ```

- S-Expressions:

    ```racket
    (define f
      (lambda (x)
        (let ((y (* x x)))
          (if (> x 0)
              (+ y 1)
              #f))))
    ```

- mixed I- and S-Expressions:

    ```racket
    define f
      lambda (x)
        let
            y (* x x)
          if (> x 0)
             + y 1
             : #f
    ```

## Install
- install from [Hackage](https://hackage.haskell.org/package/haskeme) with `cabal`:

    ```
    cabal install haskeme
    ```

- clone from [GitHub](https://github.com/jumper149/haskeme) and compile with `cabal`:

    ```
    git clone https://github.com/jumper149/haskeme.git
    cd haskeme
    cabal build
    ```

- clone from GitHub and compile with `ghc` (not recommended, use this [PKGBUILD](https://aur.archlinux.org/cgit/aur.git/tree/PKGBUILD?h=haskeme) as a template)

- install from [AUR](https://aur.archlinux.org/packages/haskeme/) (only ArchLinux-Users)

### Dependencies
- `ghc` (make)
- `cabal` (opt. make)