addVectors is a function definition, so it doesn't actually do anything until you apply it. In addThree you would use it like this

addThree vec1 vec2 vec3 = let interm = addVectors vec1 vec2 in addVectors interm vec3

or

addThree vec1 vec2 vec3 = addVectors interm vec3 where interm = addVectors vec1 vec2

or

addThree vec1 vec2 vec3 = addVectors (addVectors vec1 vec2) vec3

or

addThree vec1 vec2 vec3 = vec1 `addVectors` vec2 `addVectors` vec3

with the last one looking really nice. In the first two I bind the result to an intermediate variable; in the third the intermediate result is used inline; and the last one is basically the same as third, but the function is used as an infix. On Mon, Jun 27, 2011 at 5:51 PM, Roelof Wobben wrote:

Hello,

Im stil reading chapter4

Now we have this : addVectors (x1, y1) (x2, y2) = (x1 + x2, y1 + y2)

do I understand it that the outcome of x1+x2 will be saved in the last expression x1 + x2

But on which variable can the outcome be found.

Roelof

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