# lec03 - (* binding - reminder about let and letrec *) let...

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(* binding - reminder about let and letrec *) let foo(x) = x+1 in let bar(x) = foo(x-1) in bar(3110) let foo(x) = x+1 and bar(x) = foo(x-1) (* unbound *) in bar(3110) let rec foo(x) = x+1 and bar(x) = foo(x-1) in bar(3110) (* functions foo and bar can refer to themselves and each other *) let rec x=1 and y = x+1 in x+y (* example: computing square roots *) let squareRoot(x) = let rec (* numerical accuracy *) delta = 1e-12 (* returns true iff the guess is good enough *) and goodEnough(guess) = abs_float(guess *. guess -. x) < delta (* return a better guess by averaging it with x/guess *) and improve(guess) = (guess +. x /. guess) /. 2.0 (* Return the square root of x, starting from an initial guess. *) and tryGuess(guess) = if goodEnough(guess) then guess else tryGuess(improve(guess)) in (* start with a guess of 1.0 *) tryGuess(1.0) let square (x) = x *. x (* form of function definitions we have been using, float * float -> float *) let sum(x,y) = x +. 2. *. y (* shorthand for pattern matching of tuple, as seen in recitation *)

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## This note was uploaded on 10/25/2009 for the course PHYS 2214 at Cornell.

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lec03 - (* binding - reminder about let and letrec *) let...

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