src/utilities.lisp (compose): Handle the case of zero arguments.

[sod] / src / utilities.lisp

diff --git a/src/utilities.lisp b/src/utilities.lisp
index bdcdf80..cb6f0cc 100644 (file)
--- a/src/utilities.lisp
+++ b/src/utilities.lisp
@@ -843,7 +843,7 @@
 ;;; Functions.
 
 (export 'compose)
-(defun compose (function &rest more-functions)
+(defun compose (&rest functions)
   "Composition of functions.  Functions are applied left-to-right.
 
    This is the reverse order of the usual mathematical notation, but I find
@@ -854,7 +854,9 @@
   (labels ((compose1 (func-a func-b)
             (lambda (&rest args)
               (multiple-value-call func-b (apply func-a args)))))
-    (reduce #'compose1 more-functions :initial-value function)))
+    (if (null functions) #'values
+       (reduce #'compose1 (cdr functions)
+               :initial-value (car functions)))))
 
 ;;;--------------------------------------------------------------------------
 ;;; Variables.