Ilya Zakharevich on Wed, 26 Jun 2002 11:48:58 -0400

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Re: [PATCH 2.2.2] mneumonics for flags

On Wed, Jun 26, 2002 at 04:37:40PM +0200, Bill Allombert wrote:
> > As far as I can see it, the M flag for arguments is not included in
> > 2.2.3.  Any particular reason for this?

> 1) This patch create ambiguities in the GP grammar.
> Runge-Kutta/Known-Prime is already a valid GP expression.
> Giving it a different meaning in some context is creating ambiguities.

This is not anything new: a lot of arguments are treated similarly:

 default(Runge-Kutta/Known-Prime, 1)
  ***   unknown default: Runge-Kutta/Known-Prime.

> 2) You cannot store flag values in variable, so something like
> flag=6; if(x==1,flag+=1024) 
> cannot be translated to use symbolic flag

Of course you can.  All that is needed is extending the logic to treat
t_STRING arguments similarly.  (Do not remember whether this is
already present in the patch, but this is trivial to patch.)

> With the current way GP parse its code, there is no performance penalty
> to put Runge-Kutta/Known-Prime in a string "Runge-Kutta/Known-Prime",
> which resolves the ambiguity.

See default().

> With the GP2C parser, post-processing can easily be implemented to
> translate flag string into numerical value at compile time.

I'm confused: Is not this a plus?

> 3) This patch does not provide a similar interface to libpari programming.
> It is important that libpari and GP interface are kept on a par.

???  The parse_option_string() API is available...