Fixing Empty Module Evaluation in Racket

Empty Module Evaluation in Racket is a puzzling issue where running a module doesn’t produce any output or visible effect.

This often confuses developers transitioning from imperative languages to Racket’s functional-first model.

The problem typically arises from misunderstanding how modules work: a Racket module must explicitly export functions or include expressions for evaluation.

If #lang racket is specified but all code is wrapped in definitions (e.g., (define (foo x) (* x x))), running the module will appear to do nothing since no expression is evaluated.

To resolve this, add a direct evaluation expression, such as (display (foo 5)).

Alternatively, if the module is meant to export functions for reuse, include a (provide foo) statement.

Debugging tools like raco test can help identify unused or unevaluated code.

For larger projects, modularize by splitting functionality into multiple modules and explicitly testing each.

Understanding module behavior in Racket ensures your programs produce the intended outputs while remaining idiomatic.