On Sun, Jan 25, 2009 at 05:34:35AM +0000, John Hartnup wrote:

2009/1/24 Brent Yorgey :

...

map ($5) [(+1), (^2), abs]

which evaluates to [6,25,5].

Just to check I understand correctly - you're using ($) to 'promote' an expression into a function, in order that it may be used in higher order functions?

In this case, I'm using ($) to *make* a higher-order function---($5) is a function which takes its argument (which must be a function) and applies it to 5. (I'm assuming you're familiar with 'operator sections', if you aren't I can explain that too.) -Brent