On 22 March 2012 04:59, Jonathan Lang <datawea...@gmail.com> wrote: > My understanding is if you want to count by threes, starting at 2 and ending > at 14, you should be able to write: > > 2, 5 ... 14
That certainly looks very intuitive, and it is similar to what I would write in an email. The only annoyance is that I have to do a bit of mental arithmetic. But I guess that's ok. Especially since most of the time you'd probably want to write 2,5...* anyway. > So: > > 1, 3 ... 13 # same as 1,3,5,7,9,11,13 > 1 ... 10 # same as 1,2,3,4,5,6,7,8,9,10 > 1, 2, 4 ... 100 # same as 1,2,4,8,16,32,64 That last one doesn't work on Rakudo :-( > Meanwhile, using Whatever for the test condition means "keep the series going > indefinitely": > > 1, 3 ... * # every positive odd number. > 1 ... * # all counting numbers. > 1, 2, 4 ... * # all powers of 2. Yeah, and those are very convenient. > And using '...^' instead of '...' changes the default final test condition > from '> $n' to '>= $n': > > 1, 3 ...^ 13 # same as 1,3,5,7,9,11 > 1 ...^ 10 # same as 1,2,3,4,5,6,7,8,9 > 1, 2, 4 ...^ 100 # same as 1,2,4,8,16,32,64 Ok. I hadn't thought of doing that. > In short, what Damian is talking about is the more powerful and reliable use > of the syntax; but the above approach (assuming it has been properly > implemented) is a more intuitive use that covers the most common cases. Make > common things easy, and make uncommon things possible. Yeah. > > Likewise, using Whatever in conjunction with operators is there to provide an > intuitive way to calculate the next term from the previous one(s): > > 1, *+2 ... 13 # start at 1, step by 2s, stop at 13. > 1, 1, *+* ... * # each new term is the sum of the previous two. Oh! That second one is cool. a one line implementation of the Fibonacci sequence. Cheers, Daniel. -- I'm not overweight, I'm undertall.
