https://github.com/eatonphil/bsdscheme

A Scheme (R7RS) implementation written in D
https://github.com/eatonphil/bsdscheme

Last synced: 3 days ago
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A Scheme (R7RS) implementation written in D

• Host: GitHub
• URL: https://github.com/eatonphil/bsdscheme
• Owner: eatonphil
• License: bsd-3-clause
• Created: 2017-10-11T16:38:42.000Z (about 7 years ago)
• Default Branch: master
• Last Pushed: 2018-09-03T02:48:42.000Z (about 6 years ago)
• Last Synced: 2024-10-13T04:13:06.184Z (about 1 month ago)
• Language: D
• Homepage:
• Size: 128 KB
• Stars: 58
• Watchers: 4
• Forks: 2
• Open Issues: 12
• Metadata Files:
  • Readme: README.md
  • License: LICENSE.md

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README

        
# BSDScheme

[![CircleCI](https://circleci.com/gh/eatonphil/bsdscheme.svg?style=svg)](https://circleci.com/gh/eatonphil/bsdscheme)

This is a Scheme implementation written in D intended to eventually

support Scheme R7RS. There is an interpreter backend which is more

mature and there is a compiler backend that targets D.

## Installation

### Mac

```

$ brew install ldc

$ make

```

### FreeBSD

```

$ doas pkg install ldc

$ make

```

## Examples

### Recursion

```

$ cat examples/recursion-tco.scm

(define (exp base pow accum)

  (if (= pow 0)

      accum

      (exp base (- pow 1) (* accum base))))

(define (main)

  (display (exp 2 100 1))

  (newline))

$ ./bin/bsdi examples/exp.scm

1267650600228229401496703205376

```

### Read/eval

```

$ cat examples/read-eval.scm

(display (eval (read "(+ 1 2)")))

(newline)

$ ./bin/bsdi examples/read-eval.scm

3

```

### REPL

```

$ ./bin/bsdi

BSDScheme v0.0.0

> (define (show it) (display it) (newline))

> (show '(1 2 3))

(1 2 3)

> (show (vector-ref #(1 2 3) 1))

2

```

### Compiler (and Macros)

```

$ cat examples/my-let.scm

(define-syntax my-let*

  (syntax-rules ()

    ((_ ((p v)) b ...)

     (let ((p v)) b ...))

    ((_ ((p1 v1) (p2 v2) ...) b ...)

     (let ((p1 v1))

       (my-let* ((p2 v2) ...)

		b ...)))))

(define (main)

  (my-let* ((a 1)

            (b (+ a 2)))

           (display (+ a b))

           (newline)))

$ ./bin/bsdc examples/my-let.scm

$ ./a

4

```

## Current state

* Supported:

  * Literals: strings, characters, boolean, vectors, lists, pairs

  * Read / eval / include

  * Comments

  * Command-line REPL

  * `if`, `let`, `define`, `begin` tail calls optimized (interpreter only)

  * R7RS Libraries (interpreter only)

  * Basic define-syntax/syntax-rules support (not hygienic)

* Missing (but planned, R7RS is the obvious goal):

  * Labelled let

  * D FFI

  * Threading support

## Testing

BSDScheme uses the [btest](https://github.com/briansteffens/btest) test framework.