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Subject: Let rec trouble

To: caml-list@inria.fr

Date: Sat, 25 Jul 1998 15:06:38 -0400 (EDT)

From: "Christopher Oliver" <oliver@fritz.traverse.com>

Message-Id: <E0z09eQ-00007g-00@fritz.traverse.net>

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);;

**Next message:**Pierre Weis: "Re: Let rec trouble"**Previous message:**Xavier Leroy: "Re: Thinking about ICFP'98 programming contest..."**In reply to:**Norman Davis: "Thinking about ICFP'98 programming contest..."**Next in thread:**Pierre Weis: "Re: Let rec trouble"**Reply:**Pierre Weis: "Re: Let rec trouble"**Maybe reply:**Christopher Oliver: "Re: Let rec trouble"**Messages sorted by:**[ date ] [ thread ] [ subject ] [ author ]

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