This example is application, that can evaluate lambda expressions. For more about lambda calculus, see wikipedia. The application output each reduction step by step.

You need some library installed before running the example. Type the following command to install them.

pip install -r requirements.txt

You can then run the application by executing run.py script.

python ./run.py

It will show you command line, where you type your lambda expressions to evaluate.

For example take this lambda expression.

((lambda var y. ((lambda z. ((lambda f. (z f)) z)) var)) 3 7)

The program will output following lines.

((lambda var y. ((lambda z. ((lambda f. (z f)) z)) var)) 3 7)
((lambda y. ((lambda z. ((lambda f. (z f)) z)) 3)) 7)
((lambda z. ((lambda f. (z f)) z)) 3)
((lambda f. (3 f)) 3)
(3 3)

Author: Patrik Valkovič

Licence: GPLv3