Composition operator [was: Re: Records in Haskell]

On 01/12/2012 07:06 AM, Matthew Farkas-Dyck wrote:

On 09/01/2012, Greg Weber wrote:

...

Note that a move to a different operator for function composition (discussed in dot operator section) would make things easier to parse:

b<~ .a

where the unicode dot might be even nicer.

I told you so (^_^)

Unicode dot (∘) would be optimal, since that's what it's for. If to type '∘' is awkward, then one can use (Control.Category.<<<). We need not (and, in my opinion, should not) define another operator.

Is ∘ (U+2218 RING OPERATOR)* in Prelude yet? We should propose that.** I checked my compose-key (Linux) and it can produce middle-dot · (U+00B7 MIDDLE DOT) with "Compose . -", but not ∘ in any way***. If we use the proper Unicode operator ∘, then let's make a wiki page for all the common OSes/input methods, saying how to input it (aside from copy/paste). Is there anything on the Web somewhere already? Did Perl do this ( - I think they introduced some Unicode-based syntax)? There's http://www.haskell.org/haskellwiki/Unicode-symbols , which has some information (none of which let me write ∘ in an e-mail without using copy/paste). * found out using http://www.decodeunicode.org/ ** "(negate ∘ (+ 1)) 3" doesn't work in my ghci 7.0.3 with no command-line options (and a UTF-8 system locale and UTF-8-compatible terminal, as is typical these days). *** I checked the list in /usr/share/X11/locale/en_US.UTF-8/Compose