Henning Thielemann <[EMAIL PROTECTED]> wrote: > Sometimes I believed that I understand this reason, but then again I > do not understand. I see that left-associative (++) like in > ((a0 ++ a1) ++ a2) ++ a3 > would cause quadratic time. But (++) is right-associative and > 'concat' is 'foldr'. They should not scan the leading lists more than > once. Also > http://en.wikipedia.org/wiki/Difference_list > doesn't answer this question. Where exactly is the problem? >
| The shows functions return a function that prepends the output String | to an existing String. This allows constant-time concatenation of | results using function composition. I figure it's (constant vs. linear) vs. (linear vs. quadratic), for more involved examples. -- (c) this sig last receiving data processing entity. Inspect headers for past copyright information. All rights reserved. Unauthorised copying, hiring, renting, public performance and/or broadcasting of this signature prohibited. _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
