Lambda: A lambda calculus interpreter

Features

• A complete lambda calculus grammar with ! instead of λ for programmer convenience
• Beta reduction, alpha renaming
• Variable definitions for organization and readability
• Definition imports from local files
• Library imports (stdlib, bool, math)
• Display functionality for pure functions, booleans, and numerals
• Native numerals support
• Comments

Examples

/* A basic example */
let first = !x.!y.x;
print first a b; /* Prints (a) */

/* Library imports */
import bool;

print true a b; /* Prints (a) */
printbool true; /* Prints true */
printbool false; /* Prints false */
printbool true false true; /* Prints false */

/* Numerals */
import math;

print 2; /* Prints (!a2.!a3.a2 (a2 (a3)))*/
printnum 5; /* Prints 5 */
printnum (!a2.!a3.a2 (a2 (a3))); /* Prints 2 */
printnum succ 3; /* Prints 4 */
printnum pred 2; /* Prints 1 */
printnum add 3 5; /* Prints 8 */

Compilation

make

Usage

./lambda file.lmb Write modules in same directory as base .lmb file and save with the .lmh extension. Import with

import modulename.lmh;