A million times this. The syntax is not difficult to see, but the action seems mysterious. The article gives an example > : buzz? 5 mod 0 = IF ." Buzz" TH

A million times this. The syntax is not difficult to see, but the action seems mysterious. The article gives an example > : buzz? 5 mod 0 = IF ." Buzz" THEN ; Seems to work okay. What about immediate mode? > 10 5 mod 0 = IF ." Buzz" THEN ; action is not a function Well, I guess that does it for me. Factor, another stack-based languages, has a more legible version of this, where you can push an anonymous lambda onto the stack. As I recall from my days of programming HP-48's, that used a similar mechanism. (Not checking my syntax here) > 5 mod 0 = << "buzz" print >> if Would have a similar effect. Each entry makes sense -- the << switches from immediate mode to store mode (or some similar concept), and everything ends up on the stack. "If" is just a function that takes a boolean and a closure: > 10 level: 0 ; stack: [10] > 5 level: 0 : stack: [10 5] > mod level: 0 ; stack [0] > 0 level: 0 ; stack [0 0] > = level: 0 ; stack [true] > << level: 1 ; stack [true] [] > "buzz" level: 1 ; stack [true] ["buzz"] > print level: 1 ; stack [true] ["buzz" print] > >> level: 0 ; stack [true pointer_to_function] > if "buzz" level: 0 ; stack [] But I don't understand what Forth is doing.