[REBOL] Re: variable scopes and recursive func
From: mokkel::gmx::de at: 11-Apr-2005 1:03
Ok, last time - I hope. :-)
If I'm right the reason why the error came up at the first empty directory
and if there has been none, then only the first subtree is traversed,
because of the recursive rebinding of the word 'aFile to the repeat block.
While recursing down the first branch of the directory tree the block gets
all the time bound to a new version of 'aFile. Upon returning back from
the recursion the function one level up doesn't find any more the 'aFile
from before the recursive call and thus the test doesn't work or even
fails. Fails when 'aFile has been bound to no value in the recursion when
the directory was empty or to the last value of the file in the deepest
directory, which just gets added as often as during the walk up in the
tree some files (no directories) are encountered, because always the
second block of 'either gets executed.
Just a question to somebody who might know: One of the reasons why the
binding mechanisms of Rebol are necessary is to make the keywordlessness
possible, else something like 'repeat wouldn't be possible, right ???
But nevertheless I think these binding issues should be one of the first
things to be explained to a newcomer. It is an important property of Rebol
and should be treated like this. If there are chances to encounter these
things in normal life they have to be explained appropriately already on
the beginning and not on some articles (Ladislavs Bindology) or some
sidenote in the documentation that a function changes it's body argument.
Without deeper glue of Rebol it's hardly to get the reason and just simply
using hints like using copy/deep on a block in some circumstances is hard
to remember and hard to explain. Thus if Rebol is like this it should be
put on the frontplate. ????!!!!
On Sun, 10 Apr 2005 23:43:04 +0300, Michael Berg <[mokkel--gmx--de]> wrote: