Adding 'switch' word to sequences-lib.

extra/sequences/lib/lib-docs.factor

@@ -27,3 +27,14 @@ HELP: enumerate
 { $values { "seq" sequence } { "seq'" sequence } }
 { $description "Returns a new sequence where each element is an array of { index, value }" } ;
 
+HELP: switch
+{ $values { "x" number } { "y" number } { "seq" sequence } } 
+{ $description "Swaps the values between indices 'x' and 'y' in the sequence." }
+{ $examples
+  { $example 
+    "USING: sequences.lib ;"
+    "1 2 \"asdf\" [ switch ] keep"
+    "\"adsf\"" }
+} ;
+
+

extra/sequences/lib/lib.factor

@@ -173,3 +173,8 @@ USE: random
 : enumerate ( seq -- seq' )
     <enum> >alist ;
 
+! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
+
+: switch ( x y seq -- )
+    3dup swap [ nth ] dip [ [ move ] keep ] 2dip rot set-nth ;
+