1 files changed, 24 insertions, 0 deletions
diff --git a/pypi/utils.scm b/pypi/utils.scm
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index 0000000..88ec879
--- /dev/null
+++ b/pypi/utils.scm
@@ -0,0 +1,24 @@
+(define-module (pypi utils)
+  #:use-module (ice-9 match)
+  #:use-module (srfi srfi-69)
+  #:use-module (guix packages)
+  #:export (all-combinations))
+
+; Combinatorics
+
+(define (combinations lst len)
+  (cond ((= len 0)
+          '(()))
+        ((null? lst)
+          '())
+        (else (append (map (lambda (rest) (cons (car lst) rest))
+                           (combinations (cdr lst) (- len 1)))
+                      (combinations (cdr lst) len)))))
+
+(define (all-combinations lst)
+  (apply
+    append
+    (map
+      (lambda (len)
+        (combinations lst len))
+      (cdr (iota (+ 1 (length lst)))))))