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[REBOL] Re: The evaluation semantics

From: henrik::webz::dk at: 3-Sep-2005 14:01

On Aug 30, 2005, at 9:50 AM, Behrang Saeedzadeh wrote:
> Hi > > I'm kinda new to REBOL. Actually I was a member of this list about two > years ago and I was registered with my Yahoo! account. I felt like > that I'm really missing REBOL so I've joined the list once again :-) > > In the online manual at > it's written that: > > "The values and words of a block are always evaluated from first to > last... > " > > So I expected the following statement, without the parantheses of > course, return 6 but it is erroneous: > > length? "boat" + 2 > > Can someone please explain the reason behind this behaviour?
That's because length? "boat" returns it's value to the physical left of itself, e.g.: 4 <- length? "boat" and not length? "boat" -> 4 + requires a value on each side where the one on the left, returns a value to its right, e.g.: <value> -> + <- <value> but your statement produces: <- <value> + <- <value> The (very) new Wikibook has a bit about this, actually: Programming:REBOL#Simple_Programming_in_the_Console The part about parentheses is not entirely accurate yet, but it should fit with what you need. -- Regards, Henrik Mikael Kristensen