ruby/words.rb: find all words an array of letters can make

ruby/words.rb

@@ -0,0 +1,32 @@
+#!/usr/bin/env ruby
+
+WORDS = File.open("/usr/share/dict/words", &:read).lines.map do |word|
+  word.strip.downcase
+end.freeze
+
+def word?(word)
+  WORDS.include? word.downcase
+end
+
+def permute(letters, prefix: "", &cb)
+  1.upto letters.size do
+    cur_prefix = prefix + letters.first
+    test_set = letters[1..]
+
+    if letters.size > 2
+      permute test_set, prefix: cur_prefix, &cb
+    else
+      word = cur_prefix + test_set.join
+
+      if word? word
+        yield word
+      end
+    end
+
+    letters = letters.rotate
+  end
+end
+
+permute %w[u h s e t l] do |word|
+  puts word
+end