1 factor comment ! This is a comment
2 factor comment ! Factor syntax is very simple, it just contains words separated by spaces
3 factor comment ! '!' is a line comment word
4 factor comment ! "whatever" is a string word
5 factor code USING: kernel io ; ! This is a vocabulary inclusion word
6 factor code IN: testing
8 factor code : test-string ( -- )
9 factor code "this is a string" print ;
11 factor code : test ( x -- y ) ! Parenthesis define a stack effect declaration
12 factor code dup swap drop ;
14 factor code MAIN: test