Prism Racket

; Source: https://github.com/mbutterick/pollen/blob/master/pollen/private/to-string.rkt

#lang racket/base
(provide (all-defined-out))

(define (to-string x)
  (cond
    [(string? x) x]
    [(or (null? x) (void? x)) ""]
    [(or (symbol? x) (number? x) (path? x) (char? x)) (format "~a" x)]
    ;; special handling for procedures, because if a procedure reaches this func,
    ;; it usually indicates a failed attempt to use a tag function.
    ;; meaning, it's more useful to raise an error.
    [(procedure? x) (error 'pollen "Can't convert procedure ~a to string" x)]
    [else (format "~v" x)]))