Modularisation of reduce with functional programming as described by Hughes http://ipaper.googlecode.com/git-history/8070869c59470de474515000e3af74f8958b2161/John-Hughes/The%20Computer%20Journal-1989-Hughes-98-107.pdf

reduce.coffee

#  a function that takes a function and returns a function
reduce = (operation) ->
  # the returned function accepts a list
  (list) ->
    # and applies the operation passed to the outer function recursively to the list 
    if list.length > 2
      return operation list[0], reduce(operation)(list.slice(1, list.length))
    # until it is empty
    else
      return operation list[0], list[1]

# basic mathematical operations that take two arguments
add      = (a, b) -> a + b
multiply = (a, b) -> a * b

# combine these operations with reduce to create specialised reduce functions
sum         = reduce add
factorial   = reduce multiply


console.log()
console.log sum [3 .. 6] # 3 + 4 + 5 + 6
console.log()
console.log factorial [2 .. 4] # 2 * 3 * 4