From: "David A. Black" <dblack@...>
Date: 2009-01-31T20:52:39+09:00
Subject: Re: global generator of unique symbols

Hi --

On Sat, 31 Jan 2009, Thomas Hafner wrote:

> Hello,
>
> is there a global generator of unique symbols? See article
> <r98456-qlb.ln1@faun.hafner.nl.eu.org> why that can be needed. There I
> have defined myself a generator, but that's no real solution: if
> software is going to be put together from different libraries, only
> one common generator should be used by all software parts to prevent
> symbol clash.
>
> With ``generator of unique symbols'' I mean: the first time since
> program start it will generate any symbol. Any other time it will
> generate a symbol that differs from all already generated symbols.

Based on a 2005 post from Jeremy Kemper, based in turn on a response
from Ryan Leavengood:

   $unique_symbol = 'AAAAAAAA'
   def generate_symbol
     $unique_symbol.succ!.to_sym
   end

As James Gray pointed out in the same thread, be careful with runaway
symbol generation, since symbols aren't garbage collected.


David

-- 
David A. Black / Ruby Power and Light, LLC
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