Add Bogosort in Factor

CONTRIBUTORS.md

@@ -35,4 +35,5 @@ This file lists everyone, who contributed to this repo and wanted to show up her
 - Cyrus Burt
 - Patrik Tesarik
 - Ken Power
-- PaddyKe
+- PaddyKe
+- nic-hartley

contents/bogo_sort/bogo_sort.md

@@ -45,6 +45,8 @@ In code, it looks something like this:
 [import:16-18, lang:"nim"](code/nim/bogo_sort.nim)
 {% sample lang="ruby" %}
 [import:12-16, lang:"ruby"](code/ruby/bogo.rb)
+{% sample lang="factor" %}
+[import:10-12, lang:"factor"](code/factor/bogo_sort.factor)
 {% sample lang="f90" %}
 [import:24-32, lang:"fortran"](code/fortran/bogo.f90)
 {% sample lang="st" %}
@@ -93,6 +95,8 @@ We are done here!
 [import, lang:"nim"](code/nim/bogo_sort.nim)
 {% sample lang="ruby" %}
 [import, lang:"ruby"](code/ruby/bogo.rb)
+{% sample lang="factor" %}
+[import, lang:"factor"](code/factor/bogo_sort.factor)
 {% sample lang="f90" %}
 [import, lang:"fortran"](code/fortran/bogo.f90)
 {% sample lang="st" %}

contents/bogo_sort/code/factor/bogo_sort.factor

@@ -0,0 +1,25 @@
+! There's no built-in "is sorted" function, so let's make one:
+USING: locals ;
+: sorted? ( seq -- ? )
+  2 clump ! split it up into overlapping pairs
+  ! so now, for example, { 1 2 3 } has turned into { { 1 2 } { 2 3 } }
+  ! and now we make sure that for every pair, the latter is >= the former
+  [| pair | pair first pair last <= ] all?
+;
+
+USING: random ;
+: bogosort ( seq -- seq' )
+  ! `dup` duplicates the array, because `sorted?` pops its reference to it
+  ! randomize works in-place
+  ! so we `randomize` `until` it's `sorted?`
+  [ dup sorted? ] [ randomize ] until
+;
+
+! WARNING: Increasing this number beyond 5 or so will make this take a very long time.
+!          That said, if you have an afternoon to kill...
+5 <iota> >array randomize ! generate a random array to demo
+dup .                     ! show the array
+bogosort                  ! bogosort it
+.                         ! show it again
+
+