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Re: Error of using <integer>?

From: Per Bothner <per at bothner dot com>
To: Yaroslav Kavenchuk <kavenchuk at gmail dot com>
Cc: kawa <kawa at sourceware dot org>
Date: Thu, 24 Jan 2008 08:54:01 -0800
Subject: Re: Error of using <integer>?
References: <f19ba4b50801240237n46cde33ej317e639cc3a8c046@mail.gmail.com>

Yaroslav Kavenchuk wrote:

(define (!i x :: <integer>) :: <integer>
  (letrec ((!!i (lambda (i :: <integer> k :: <integer>) :: <integer>
               (if (= i 1)
                   k
                   (!!i
                     (- i 1)
                     (* i k))))))
    (!!i x 1)))

#|kawa:36|# (define x (!i 2352))
#|kawa:37|# (define x (!i 2353))
java.lang.StackOverflowError


It works for me.  But I'm running on GNU/Linux (Fedora 8),
which may mean I have a different default stack size.

I looked at the generated bytecode for the two versions:
The untyped version is tail-recursive (i.e. is compiled
to a loop), while the typed one isn't (i.e. is compiled
to a recursive call).

I'll take a look to see if I can figure out why.
--
	--Per Bothner
per@bothner.com   http://per.bothner.com/

References:
- Error of using <integer>?
  - From: Yaroslav Kavenchuk

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