Memoize

factor_lexical_vars

IN: scratchpad auto-use "5" 3 [| m n | m string>number :> m m n + . ] call
8
 
IN: scratchpad auto-use "5" 3 [| m n | m string>number :> m m ] call
 
--- Data stack:
5

http://docs.factorcode.org/content/article-locals-examples.html