[REBOL] Re: REBOL embedded $variables regexp/no
From: joel:neely:fedex at: 10-Dec-2002 13:35
Hi, Gabriele,
Gabriele Santilli wrote:
> JN> Please, everyone, before complaining about the punctuation,
> JN> get over it and look at the real point; that expression says
> JN> (compactly) the equivalent of this:
> [...]
>
> Joel, you are right, but also consider that if I look at it, I
> don't understand what it is doing.
>
I completely agree, but there are multiple situations that give
me trouble when trying to read and digest some notation:
1) When I'm not familiar with it;
2) When it is so condensed as to be cryptic and/or error prone;
3) When it is so verbose that it takes much writing to say
simple things.
The first is simply a matter of education and experience. The
second is certainly an accusation leveled at some notations. The
third is harder to detect, but certainly affects productivity and
scalability.
> Of course, that applies to every language, but if you look at:
>
> replace/all s "tetx" "text"
>
> you can guess what it is doing even if you don't know REBOL at
> all.
>
But the second argument is restricted to specific literals; there
isn't an option to express a more general case (such as "run of
whitespace of arbitrary length").
> >> digits: charset "1234567890"
> >> chars: complement digits
> >> pattern-replace "Replace 5248 with a #" [any chars] [some digits] "#"
> == "Replace # with a #"
>
That's a nice hack (seriously!), but isn't it odd that REBOL allows one
to build anonymous functions ...
map some-block func [x] [x * x - 1]
... but we have to use nested definitions with explicit names for all
but the most trivial cases of PARSE rules???
> Matching a pattern and defining a grammar are two different
> things, of course.
>
I agree totally!
> However, I am convinced that grammars are much more general and
> useful than patterns.
>
I'd prefer to say that each has its own strengths and weaknesses.
A spreadsheet is a more general tool than a four-function calculator,
but there are situations where a calculator is more than adequate
(and requires much less overhead than firing up a full-featured
spreadsheet). (OF course, this is a poor analogy!)
I've encountered *many* situations where it would be very convenient
to write a pattern for some specific thing I'm looking for, rather
than having to write a comprehensive grammar that includes all the
other stuff I don't care about.
I simply think each has it's place.
-jn-
--
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Joel Neely joelDOTneelyATfedexDOTcom 901-263-4446
