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[REBOL] Re: How do I handle an unset! item as a parameter to other words

From: gerardcote:sympatico:ca at: 2-Dec-2002 21:34

Hello Jan, You wrote :
> That's the expected behaviour. Function 'what accepts nothing > and returns nothing. In C or Java parlance it's return type would > be 'void. > It does print something on the console, but that's a side effecting > operation. Other (static!) languages would spell it very clearly: > Ocaml ------ what: ( ) > Haskell ----- what :: IO ( ) > but unfortunately Rebol does not care that much for the > return types, because it can only figure them out dynamicly; > that is, after executing statements or expressions. > That's what the 'type? function is telling you: > type? what > == unset > It means that there is no real object returned from the 'what > function. > If you want to intercept output from functions like this then > you need to deal with the standard output itself. Look at the script > library - consoleio.r, keyb.r, etc.
Thank you very much for the explanation. I'll look at these other scripts you suggest. Cheers, Gerard