Hi Jeff,
| You can write the section (+ x) to specify a function to add `x' to
| something. That's great, then you need to specify a function for
| subtracting `x' from something.
This is why the "subtract" function is included in the Prelude:
Prelude> map (subtract 1) [1..10]
[0,1,2,3,4,5,6,7,8,9]
Prelude>
| No so, of course. (- x) means `negate x'. Bummer. What an
| unpleasant bit of asymmetry!
Of course, (-x) as a negative number probably has more of a precedent
than (-x) as the "subtract x" reading. Some folks have suggested a
different notation for sections in which an underscore indicates the
position of missing arguments. That would make (_-x) look different
from (-x), and from (_-_), but it doesn't look particularly pretty
either ...
All the best,
Mark
