# Crate blc [−] [src]

**blc** is an implementation of the
binary lambda calculus in Rust.

## Binary lambda calculus basics

Binary lambda calculus (BLC) is a minimal, purely functional programming language based on a binary encoding of the untyped lambda calculus with De Bruijn indices.

Lambda terms have the following representation in BLC:

term | lambda | BLC |
---|---|---|

abstraction | λM | 00M |

application | MN | 01MN |

variable | i | 1^{i}0 |

Since BLC programs are basically lambda calculus terms, they can be applied to other terms. In order to be applicable to binary (but not BLC-encoded) input, it has to be lambda-encoded first. Bytestrings are lambda-encoded as Church lists of bytes and bytes are lambda-encoded as Church lists of lambda-encoded bits.

Bits 0 and 1 are lambda-encoded as Church booleans:

bit | lambda | BLC |
---|---|---|

0 | λλ2 (true) | 0000110 |

1 | λλ1 (false) | 000010 |

Example: BLC-encoding steps for a byte representing the ASCII/UTF-8 encoded letter 'a':

encoding | representation |
---|---|

decimal | 96 |

binary | 01100001 |

lambda | λ1(λλ2)(λ1(λλ1)(λ1(λλ1)(λ1(λλ2)(λ1(λλ2)(λ1(λλ2)(λ1(λλ2)(λ1(λλ1)(λλ1)))))))) |

BLC (hex) | 16 16 c 2c 10 b0 42 c1 85 83 b 6 16 c 2c 10 41 0 |

## Reexports

`pub use self::execution::run;` |

`pub use self::encoding::binary::to_bits;` |

`pub use self::encoding::binary::from_bits;` |

## Modules

encoding |
BLC-relevant encodings |

execution |
Binary lambda calculus execution |