https://github.com/phipsgabler/mini-lambda

A small normalizer for lambda calculus, implementing (almost) everything from scratch.
https://github.com/phipsgabler/mini-lambda

lambda-calculus parser-combinators

Last synced: 8 months ago
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A small normalizer for lambda calculus, implementing (almost) everything from scratch.

• Host: GitHub
• URL: https://github.com/phipsgabler/mini-lambda
• Owner: phipsgabler
• License: unlicense
• Created: 2015-11-06T19:00:04.000Z (over 10 years ago)
• Default Branch: master
• Last Pushed: 2019-10-12T20:03:47.000Z (over 6 years ago)
• Last Synced: 2025-01-22T03:33:03.739Z (over 1 year ago)
• Topics: lambda-calculus, parser-combinators
• Language: Haskell
• Size: 22.5 KB
• Stars: 1
• Watchers: 2
• Forks: 0
• Open Issues: 1
• Metadata Files:
  • Readme: README.md

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README

          
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# Mini-Lambda #

The initial purpose of this project was just to try setting up a real-world Haskell project with stack, cleanly written and tested.

It ended up in an interesting task of understanding and implementing a normalizer for the untyped lambda calculus.

## Usage ##

There is a command-line interface to the normalizer, which can most easily be accessed via `stack exec mini-lambda`. Currently, this does only run the full reduction and prints the result. The syntax is defined as follows:

    EXPR = VAR

      | "(" LAMBDA VAR "." EXPR ")"

      | "(" EXPR EXPR ")"

    LAMBDA = "λ" | "\\"  (a single backspace)

    VAR = (['!'..'\''] | ['*'..'-'] | ['/'..'['] | [']'..'~'])+

This means that every lambda and every application have to be fully parenthesized -- this might get improved in the future. For more details, see [Parser.hs](https://github.com/phipsgabler/mini-lambda/blob/master/src/MiniLambda/Parser.hs) (the parser combinator used is self-written, just for fun, so there's poor error handling).