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[REBOL] Re: postfix? -> prefix

From: arolls::bigpond::net::au at: 19-Jul-2001 20:50

> Anton, you're right! I never thought of trying prefix notation! Did > earlier REBOL/core's support that?
Umm.... can't remember. It's been around for a while. How early is early?
> Your observation that prefix means "stack-based" seems to clash with the > Forth approach in which an operator can be applied to one or more > results of > "preceding" operations that were "left on the stack". With prefix syntax > the operator signals an intent to operate on the result((s) of one or more > future operations. I agree that "stack-based" isn't a clear concept, but > it's definitely not "Forth-like". I may be misusing terms, but prefix > operator is more like a function, which is followed by arguments. > Russell [rryost--home--com]
More like a function, yes, easy for rebol. But they tend to grab arguments too quickly. The infix and prefix notations work against each other a bit, but infix was considered too necessary for beginners and lovers of usual math notation. Caution: when making prefix notation, watch out for - (minus) If you try:
>> - 100 10
== 10 ; you might be expecting 90 This is because the minus (-) is used here as a unary operator, taking just one argument. Therefore the above is just two values, -100 followed by 10. In such a case, the result returned is simply the last value. Anton.