Ladislav, Your 2 cents worths more than my 50 cents Thanks.
Emeka 2010/8/24 Ladislav Mecir <[email protected]> > > Dne 23.8.2010 19:26, Arie van Wingerden napsal(a): > > Indeed that is the way it works. > > In Lisp a list (when unquoted!) is always evaluated. > > In Rebol evaluation is not standard, but must be triggered by a calling > > function (outside the block). And indeed also, when a block is being > > evaluated functions within the block will be recognized and evaluated > also. > > > > 2010/8/23 Emeka<[email protected]> > > > >> Hello All, > >> > >> This where I got my conclusion. > >> > >> I mentioned before that blocks are a container type. An ordered sequence > of > >> values. Actually they are an ordered sequence of un-evaluated values. > What > >> that means is that when a block itself is evaluated the values it > contains > >> are not evaluated. The values a block contains are evaluated when a > >> function > >> is applied to the block > >> > >> > >> > http://www.codeconscious.com/rebol/articles/rebol-concepts.html#Firsttrapforbeginners > >> > >> > >> Is the last statement correct? > >> > >> > >> Emeka > >> > ...the rest snipped... > > The funny thing about the discussion above is, that although the > contributors look like being in mutual agreement, their statements > actually are not. > > Let me try to add my two cents in hope I do not add more confusion to > the subject. > > First, let's examine the expression: > > do [ > ; this is the "outer block" > length? [ > ; this is the "inner block" > 1 > ] > ] > > Such an expression is quite frequently referred to as: "The (outer) > block in the above expression is evaluated by the DO function." > > When describing, how the DO function interprets the (outer) block, the > documentation sources say, that "The values and words of the block are > computed from left to right." Notice, that the word used is not > "evaluated", but "computed". That is a necessary terminological > distinction, since the inner block is not "evaluated" in the same way as > the outer block is, it is just "computed", which actually means, that > the inner block is supplied "as is" to the LENGTH? function. In this > case, the LENGTH? function does not do any further "evaluation" of the > inner block, it just yields the length of the inner block as its result. > > Hope, that this "terminological detour" was of some help. > > -Ladislav > > P.S. the usage of the "un-evaluated values" notion I see as quite > unfortunate, since it looks more confusing than explaining. > > -- > To unsubscribe from the list, just send an email to > lists at rebol.com with unsubscribe as the subject. > > -- To unsubscribe from the list, just send an email to lists at rebol.com with unsubscribe as the subject.
