Aha, you stumbled upon the "weird" behaviour of
rebol's OP! datatypes.
>> type? :+
== op!
Yes, the infix operators (+ - * /) behave a bit differently
than other "normal" rebol functions and actions.
The explanation I remember is that an expression such as:
arg1 + arg2
becomes (internally)
+ arg1 arg2
so that it is then like any other rebol function.
In your example, the + would have jumped just in
front of the string, and then took two arguments
"boat" and 2, and tried to add them together.
You can rewrite it like this:
+ length? "boat" 2
But what we usually end up writing is:
(length? "boat") + 2
or
2 + length? "boat"
being conscious that in tight loops parens slow things down a tiny bit.
Anton.
> 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
> http://www.rebol.com/docs/core23/rebolcore-3.html 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?
>
> Thanks in advance,
> --=20
> Behrang Saeedzadeh
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