Hi Sean If you look again on the page I hit on a similar for/fold solution independently, which is now up on Rosetta
Amusingly, the Common Lisp version was submitted by a colleague of mine who I mentioned this exercise to, so no doubt there'll be some friendly banter tomorrow! So any further help pn the code golf aspects is much appreciated! -- Dan On Wed, Jun 5, 2013 at 12:05 AM, Sean Kanaley <skana...@gmail.com> wrote: > > Hello fellow Rosetta submitter! > > The regular expressions are actually pretty useful to make a functional > version shorter than the imperative one! > > First, forms with (for ...) and a bunch of (set!)'s is made functional by > (for/fold ...) where the final (values ...) functionally sets the new > values. > Second, the regexp portion can take a converted symbol instead of a > hard-coded string to save duplicate names. > > I present the following compactified implementation: > > (define-values (cei cie ie ei) > (for/fold ([cei 0] [cie 0] [ie 0] [ei 0]) > ([line (file->lines "unixdict.txt")]) > (define-syntax-rule (tally x ...) > (values (if (regexp-match? (symbol->string 'x) line) (add1 x) x) > ...)) > (tally cei cie ie ei))) > > (print-rule "I before E when not preceded by C" (- ie cie) (- ei cei)) > (print-rule "E before I when preceded by C" cei cie) > > Since the macro would be needlessly complicated with extra conditional > logic to avoid counting "cei" as "ei", it's better to just subtract at the > end. > > I was wondering if there is some way to combine things like define-values > and for/fold...in general I find that whenever I use the functional forms > of (for...), since I will by definition care about the return values, it's > inconvenient, especially in the multiple values case, to rebind the results > to the accumulators in the for form (as seen in the above example). In > other words, since the results of the functional versions of (for...) HAVE > to be in some way bound eventually (unless it's the entire program), it may > as well perform the binding outright and save the duplication of (let > ([result (for ...)]) ...). Perhaps anaphoric for (afor...) that binds "it" > or something like that, and for multiple values, it0, it1 ... > > On Tue, Jun 4, 2013 at 9:34 AM, Tobias Hammer <tobias.ham...@dlr.de>wrote: > >> Sorry for the misinformation but Eli is of course right that regexp-quote >> must be used. >> >> Example: >> >> (regexp-match? "a" "abc") >> >>> #t >>> >> (regexp-match? "." "abc") >> >>> #t ; WRONG! '.' matches every character >>> >> >> (regexp-match? (regexp-quote "a") "abc") >> >>> #t >>> >> (regexp-match? (regexp-quote ".") "abc") >> >>> #f >>> >> >> >> On Tue, 04 Jun 2013 13:57:41 +0200, Daniel Prager < >> daniel.a.pra...@gmail.com> wrote: >> >> Thanks Tobias & Eli >>> >>> I've updated my submission to use (regexp-match? sub-str str). >>> >>> [Also added the stretch goal solution, but could do with some refactoring >>> to reduce the joint line-count.] >>> >>> -- Dan >>> >> ____________________ >> Racket Users list: >> http://lists.racket-lang.org/**users<http://lists.racket-lang.org/users> >> > >
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