Let rec trouble
 Christopher Oliver
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Date:   (:) 
From:  Christopher Oliver <oliver@f...> 
Subject:  Let rec trouble 
I'm having trouble with the syntax of let rec. Consider the following program for computing Van der Waerden's bound: open Num open Nat open Big_int open Ratio let rec n k l = let rec m i = if i =/ Int 0 then Int 1 else Int 2 */ (m (pred_num i)) */ (n (k **/ (m (pred_num i))) (pred_num l)) in if l =/ Int 2 then succ_num k else m k;; print_string (string_of_num (n (Int 3) (Int 3)));; I would like to restrict the lexical scope of 'n' by replacing the first double semicolon with 'in.' I nest m precisely to capture k and l in m's lexical environment. Why is this use forbidden? I.e. Why shouldn't I be able to write: let rec n k l = let rec m i = if i =/ Int 0 then Int 1 else Int 2 */ (m (pred_num i)) */ (n (k **/ (m (pred_num i))) (pred_num l)) in if l =/ Int 2 then succ_num k else m k in print_string (string_of_num (n (Int 3) (Int 3)));; I would prefer not to define a top level symbol, and this seems an inconsistancy. Am I missing something?  Christopher Oliver Traverse Internet Systems Coordinator 223 Grandview Pkwy, Suite 108 oliver@traverse.net Traverse City, Michigan, 49684 let magic f = fun x > x and more_magic n f = fun x > f ((n f) x);;