[REBOL] Re: Help me Obi REB Kenobi! You're my only hope!
From: joel:neely:fedex at: 11-May-2002 22:26
Hi, Ed,
You've already received several good suggestions.
Ed Dana wrote:
> pick: random/seed 100.0
>
> guess: ask {What is your guess? }
>
> while [pick <> guess] [
> if [pick < guess] [ print "To low" ]
> if [pick > guess] [ print "To high" ]
> guess: input
> ]
>
> print pick
>
Let me add just a few more suggestions:
- Until you're used to the REBOL built-in vocabulary, I suggest
that you make liberal use of HELP while deciding what to call
your own words. If you had typed
help pick
and
help guess
you'd have gotten the hint that PICK was already taken, but
that GUESS was available for you to use without conflict.
- You don't need to re-seed the pseudo-random-number function
on every use. Changing to a "safe" word SECRET for the
hidden number, you can just say
secret: random 100
- Since ASK and INPUT return strings, go ahead and convert to an
integer before setting GUESS, as in
guess: to-integer ask {What is your guess? }
and
guess: to-integer input
- A purist would point out that inside the body of WHILE you
have already established that GUESS and SECRET differ; instead
of double-comparing, you can simplify to:
while [guess <> secret] [
either guess < secret [
print "Too low"
][
print "Too high"
]
guess: to-integer input
]
- With that simplification in place, you can now factor out the
PRINT and the first part of the string, as in:
while [guess <> secret] [
print [
"Too"
either guess < secret ["low" "high"]
]
guess: to-integer input
]
- Since logic! values can be used by PICK (the predefined one!)
to obtain values from a block, you can further shorten to:
while [guess <> secret] [
print ["Too" pick ["low" "high"] guess < secret]
guess: to-integer input
]
- You can further tighten up by not setting GUESS in multiple
places in the code. Just PRIN (output without newline) the
first-time prompt above the loop, then let the loop handle
the input of all guesses. This brings us down to:
secret: random 100
prin {What is your guess? }
while [secret <> guess: to-integer input] [
print ["Too" pick ["low" "high"] guess < secret]
]
print "You got it!"
- Several of these hints fall under the heading of DRY (Don't
Repeat Yourself). Whenever you find the same expression
occurring multiple times (or even similar expressions), you
might want to look for a way to eliminate the redundancy.
REBOL offers many ways to do so.
Hope this helps!
-jn-
--
; Joel Neely joeldotneelyatfedexdotcom
REBOL [] do [ do func [s] [ foreach [a b] s [prin b] ] sort/skip
do function [s] [t] [ t: "" foreach [a b] s [repend t [b a]] t ] {
| e s m!zauafBpcvekexEohthjJakwLrngohOqrlryRnsctdtiub} 2 ]
