From: Hugh Sasse <hgs@...>
Date: 2005-11-16T23:30:24+09:00
Subject: Re: static variable; behaviour in ruby?

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On Wed, 16 Nov 2005, Brian Schr=F6der wrote:

> On 16/11/05, Hugh Sasse <hgs@dmu.ac.uk> wrote:
> > Any idea how to create or simulate a static variable in ruby?
> >
> > I want to create a variable to hold state between calls of a method,
> > but have the state disappear when the method goes out of scope.
> > I could create it in some external object but then I'd need to query
> > the scoping rules, and know where i was.
> >
> > I'm trying to do an instance_eval on a string containing a method such =
as
> >    do_this x,y,z {block}
> > and I want to evaluate the block, or not, as a function of some
> > state against which x,y,z are compared.  The code will be called severa=
l
> > times, but I only want the state intialized the first time the scope
> > is entered.
> >
> > And, just to make matters worse, there could be several independent
> > calls to this method within the scope, each with its own separate
> > state.
> >
> > Maybe there's another way to do this?
> >
> >         Thank you
> >         Hugh
> >
> >
>=20
> I advise that you state your basic problem, as this seems to be a
> problem with an ugly workaround. You can probably restructure your
> problem such that this is no longer needed.

I thought the paragraph about instance_eval explained it :-).

Essentially, I have become fed up with lousy diagnostics from sed,
and have been trying to re-implement (enough of) it in Ruby, so I
hae some chance of getting the code to work. Thus I'd use code like:

   within 10, 30 {
     sub(/this/, 'that')
     sub(/thingy/, 'the other')
     # Example of munging something akin to C comments
     within /^\s+\/\*/, /\*\/\s*$/ {
       rot13 # or something
     }
   }

So I need to keep track of which patterns have matched, and clear
them when the scope (surrounding block) is gone.
>=20
> Brian
>=20
        Hugh
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