Add perm.py script

2 files changed, 44 insertions, 1 deletions

diff --git a/Makefile b/Makefile
index 4764de2..6e4ba24 100644
--- a/Makefile
+++ b/Makefile
@@ -1,6 +1,6 @@
 BINDIR = $(HOME)/bin
 
-TARGETS = mkheader.py isprime multi-send-key
+TARGETS = mkheader.py isprime multi-send-key perm.py
 
 all: $(TARGETS)
 	@echo "Nothing to be done"
diff --git a/perm.py b/perm.py
new file mode 100755
index 0000000..cabb68f
--- /dev/null
+++ b/perm.py
@@ -0,0 +1,43 @@
+#!/usr/bin/env python
+#
+# perm.py - print all possible permutations of a word
+#
+# Copyright 2009 Tobias Klauser <tklauser@distanz.ch>
+#
+# "THE BEER-WARE LICENSE" (Revision 42):
+# <tklauser@distanz.ch> wrote this file. As long as you retain this notice you
+# can do whatever you want with this stuff. If we meet some day, and you think
+# this stuff is worth it, you can buy me a beer in return
+#  Tobias Klauser
+
+
+from __future__ import generators
+import sys, os
+
+def usage():
+    print "usage: %s WORD..." % (os.path.basename(sys.argv[0]))
+
+def xcombinations(items, n):
+    if n==0:
+        yield []
+    else:
+        for i in xrange(len(items)):
+            for cc in xcombinations(items[:i] + items[i+1:], n-1):
+                yield [items[i]] + cc
+
+def xpermutations(items):
+    return xcombinations(items, len(items))
+
+def main():
+
+    if len(sys.argv[1:]) < 1:
+        usage()
+
+    for w in sys.argv[1:]:
+        print "Permutations of %s:" % w
+        for p in xpermutations(w): print " %s" % ''.join(p)
+
+if __name__=="__main__":
+    main()
+
+# vim: expandtab shiftwidth=4