one-time initialization

From: Michael Hicks (mwh@dsl.cis.upenn.edu)
Date: Thu Jan 28 1999 - 06:08:23 MET

From: Michael Hicks <mwh@dsl.cis.upenn.edu>
Message-Id: <199901280508.AAA21644@codex.cis.upenn.edu>
Subject: one-time initialization
To: caml-list@inria.fr
Date: Thu, 28 Jan 1999 00:08:23 -0500 (EST)

I wonder if anyone knows how to optimize the following (simplified for the
sake of dicussion) situation:

let global = ref None
let init i =
  global := Some i
let f () =
  match (!global) with
    Some x -> x
  | None -> failwith "not initialized";;
let g() =
  match (!global) with
    ...

Essentially, there is some global state that is initialized once, and is
used by all functions in the module. In a more realistic situation, this
state might be initialized by reading in a file. Given that following
initialization the global state never changes, it should be conceivable to
eliminate the match and dereference; on my machine (pentium 166), the match
and dereference result in about a 30% slowdown. I've fooled around with
some things, but haven't found anything that performs better than this
straightforward approach or is any more elegant.

Thanks,
Mike 

-- 
Michael Hicks
Ph.D. Candidate, the University of Pennsylvania
http://www.cis.upenn.edu/~mwh            mailto://mwh@dsl.cis.upenn.edu
"I worked with an individual who plugged his power strip back into itself
and for the life of him could not understand why his computer would not
turn on."

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