comments

util.scm

@@ -1,28 +1,39 @@
+;;; Module storing utility functions for common use.
+
 (module util (curry applied thunk just perhaps compose-symbols)
   (import scheme)
   (import chicken.base)
   (import srfi-13)
 
+  ;; Partial application function for binary functions.
   (define (curry fn a)
   (lambda (b)
     (fn a b)))
 
+  ;; Make a function applied, as per (applied +) = (lambda (ln) (+ (car ln) (cdr ln))).
   (define (applied fn)
     (curry apply fn))
 
+  ;; Take a list of expressions and wrap them in a thunk.
   (define-syntax thunk
     (syntax-rules ()
       ((_ exp ...)
        (lambda () exp ...))))
 
+  ;; Wrap a thunk in a function that discards all its arguments
+  ;; and returns the result of evaluating the thunk.
   (define (just fn)
     (lambda args
       (fn)))
 
+  ;; Haskell Maybe lifting pattern equivalent for booleans,
+  ;; apply fn to arg if arg is not false.
   (define (perhaps fn arg)
     (if arg
 	(fn arg)
 	arg))
 
+  ;; Compose the argument symbols into a new symbol, joined by '-'.
+  ;; (compose-symbols 'apple 'pear 'orange) = 'apple-pear-orange
   (define (compose-symbols . ln)
     (string->symbol (string-concatenate (intersperse (map symbol->string ln) "-")))))