On Sat, Feb 11, 2012 at 4:07 PM, Doug McIlroy <d...@cs.dartmouth.edu> wrote: > For example, this code fragment to define addition on lists > is instantly intelligible. > > instance Num a => Num [a] where > (f:fs) + (g:gs) = f+g : fs+gs > > But the formula becomes merely an obscure procession of symbols when > rewritten with the operators set off by spaces: > > ( fs : gs ) + ( g : gs ) = f + g : fs + gs
I wouldn't require them inside parentheses, but that's a very good point: the list constructor in patterns is an example of an operator where basically no one ever uses spaces. > > And it becomes too long and too subtly modulated to take in at > a glance if more spacing is added to emphasize precedence: > > ( f : fs ) + ( g : gs ) = f + g : fs + gs I would rather write (f + g) : (fs + gs), but point taken. In any case, while I would in theory support spaces around all operators, modulo counterexamples such as those presented above, I'm not proposing it and I don't think anyone is, so it's probably best to stick to discussing spaces around (.) (which I also support). Apologies for taking the discussion off topic. _______________________________________________ Haskell-prime mailing list Haskell-prime@haskell.org http://www.haskell.org/mailman/listinfo/haskell-prime
