[REBOL] Re: REBOL] Re: source code layout question
From: carl:cybercraft at: 6-Jan-2002 13:34
On 05-Jan-02, [SunandaDH--aol--com] wrote:
> Hi Carl,
> Sunanda:
>>> I also guess a preferred formating style depends largely on what
>>> the
>>> expected lifecycle of the code is. I assume code is a high
>>> maintenance item, and leave it spaced out to make modifications
>>> (in my option) easier. As an example, I was never convinced by
>>> Carl S's "mental reduction" example in Zine/2.
> Carl:
>> Well, I was convinced, and I now find the one-line version easy
>> and
>> natural to read. Also, adding any additional code /is/ simple...
>>
>> data: find data either mode [a: 1 "Active"][b: 2 "Passive"]
> It's easy to think up simple changes that would make the one-liner
> difficult to maintain:
> If Mode is True position Data at "Active", unless Mean is 5, in
> which case leave Data's position unchanged
> If Mode is False position data at "Passive" unless Median is unset,
> in which case also unset Data
> Or
> If Mode is True and Data is a series position Data at "Active"; but
> if Data is an integer, set it to zero.
> The problem is that the one-liner makes two assumptions: first that
> Data is a series; and second that the result of manipulating it
> should be a change in its position). The longer code need make
> neither of these assumptions.
> Whether those assumptions are reasonable or not is not something we
> can't tell from such an artificial example. But I do try to write
> code remembering that maintaining it is much harder than writing it.
> So if I've been as clever as I possibly can in distilling it down to
> one-liners at time of writing, my successors (including an older me)
> have little chance of maintaining it.
It's all a question of how readable the one-liner ends up being. I'd
say to a REBOL programmer that...
result: either whatever-1 [whatever-2][whatever-3]
is as readable as...
either whatever-1 [
result: whatever-2
][
result: whatever-3
]
and probably more readable in fact. And as long as the one-liners are
readable and hence can be converted into a five-liner with next to no
thought, you have two payoffs due to a more efficient program and
code that occupies a lot less lines.
Look at the above two example: With the one-liner your eyes only need
to scan left and right to understand it, (like a quick scan of the
horizon), while with the five-liner our eyes are jumping back and
forth vertically as well as horizontally. Humans are designed for
reading one-liners... (:
But I'm serious about the above, and the "left-right scanning" may be
why Joel's...
either whatever-1
[ result: whatever-2]
[ result: whatever-3]
seems so attractive. Having the blocks all on one line where possible
is nice.
> Maybe what we need is not just a prettyprinter.r but also an
> optimiser.r. That can produce runtime code which is as densely
> one-lined as possible while still functionally equivalent to the
> original. Any takers?
No, in that I would think it's probably impossible with REBOL. For
instance, how would you optomize 'blk to allow for a later...
change blk whatever
Your "code" from REBOL's point of view is all just data, remember.
--
Carl Read
