Anonymous Recursive Functions in Racket Overview This GitHub repository, owned by user "shriram," focuses on implementing anonymous recursive functions in Racket, inspired by similar features in languages like PowerShell. --- Context Anonymous Recursive Functions: Normally, recursive functions refer to themselves by name to recur. Anonymous recursion refers to a mechanism where functions can refer to themselves without explicitly naming. This concept is sometimes called an anaphoric reference. PowerShell’s $MyInvocation automatic variable demonstrates this concept. --- Implementation The repository contains a macro: lam/anon♻️ (short for "lambda with anonymous recursion"). It binds the recursive function to $MyInvocation, mimicking PowerShell's syntax. $ here is just a part of the name; it does not carry any special meaning. --- Examples The client.rkt file illustrates several use cases with varying complexity: fact: Traditional factorial function demonstrating recursion. lucas-or-fib: A function demonstrating that $MyInvocation binds correctly to the recursive call. It can compute either the Fibonacci or Lucas sequence by changing initial values. grid: Shows correct recursive binding even in nested contexts. range: Validates that variable arguments (varargs) work properly with this macro. --- Benefits and Utility Writing recursive anonymous functions usually requires naming the function using techniques like letrec, increasing verbosity and indentation. This macro allows a programmer to create recursive functions anonymously without refactoring existing lambda expressions. Enables "halfway through writing a lambda" to add recursion easily. Useful for writing helper functions inside other functions or expressions without breaking the flow or increasing nesting. --- Recommendations Do not use this macro if you program in Racket commonly, as there is already a better solution: The rec form from the mzlib library offers a cleaner way to add recursion with a meaningful function name. Advantages of rec: Evaluates to the same function as the lambda itself. Facilitates meaningful naming. Slight indentation increase. Retains full lambda functionality and capabilities. Keeps the lambda body unchanged. --- Credits James Brundage ("MrPowerShell") introduced the idea on Bluesky, showing the PowerShell $MyInvocation reference. Ali M (@deadmarshal on mastodon.social) highlighted that Forth has a RECURSE keyword serving similar purposes. --- Repository Details Name: anonymous-recursive-function Owner: shriram Visibility: Public Primary Language: Racket (100%) Files: anon-rec.rkt: Implements the lam/anon♻️ macro. client.rkt: Example usage demonstrating various recursive functions. .gitignore, LICENSE (Apache-2.0 license), README.md. Stars: 4 Forks: 0 No releases or packages published. --- License This repository is licensed under the Apache-2.0 license. --- Summary This project explores how to implement anonymous recursion in Racket by defining a macro that binds a special name for recursive calls, inspired by PowerShell's $MyInvocation. While useful as a proof of concept or convenience tool, native Racket users are advised to use existing solutions like rec from mzlib for better integration and readability. The repository includes practical examples and a clear explanation of the utility and motivations behind this approach.