Brooks

A simple lambda calculus interpreter

Note: this is not thoroughly tested, Alpha conversion may not be guaranteed to be correct.

Usage

Usage: brooks [OPTION...] files...
    --parse      Show the syntax tree
    --reduction  Do a β reduction
    --repl       Enable the REPL

Repl

<expr>                          Evaluate an expression
:b              <expr>          Do a beta reduction
:h                              Print Help
:q              <expr>          Quit
:p              <expr>          Print the generated syntax tree
:!              <cmd>           Run a shell command

Samples

λ and \ can be used interchangeably

• ID

λ> λx.x
1

• Church Numerals

λ> λf x. f (f x)
2

(Also supports just placing the number)

λ> \x. 10 x
10

• Beta Reduction

λ> :b (\x.(\f.\x.f x)(\y.x)) (\a.a)(\b.b)
λa.a

• Get syntax tree

λ> :p \x.x

(Abstraction
  (Identifier x)
  (Identifier x))

Test it out with flakes

nix run github:Trouble-Truffle/brooks -- --repl