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Another try/finally idea
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Date: 2007-12-28 (03:56)
From: Dave Benjamin <dave@r...>
Subject: Another try/finally idea
Here's another way of writing a HOF to do try/finally-like behavior to 
handle the allocation and disposal of resources. It's pretty similar to 
the one in Extlib, but it's designed to work well with the existing 
library functions:

let using resource finalize process =
     let result = process resource in
     finalize resource;
   with e ->
     finalize resource;
     raise e

With this, I can print the first line of my .emacs file in one line:

using (open_in ".emacs") close_in input_line

Common cases can be wrapped easily:

let with_open_in filename = using (open_in filename) close_in
let with_open_in_bin filename = using (open_in_bin filename) close_in
let with_open_out filename = using (open_out filename) close_out
let with_open_out_bin filename = using (open_out_bin filename) close_out

Now, getting the first line is even simpler (and more readable):

with_open_in ".emacs" input_line