Re: [exim] Idea: Predefined macros

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Author: Philip Hazel
Date:  
To: Jason_Meers, Stefan Klatt, Nigel Metheringham
CC: exim-users, W B Hacker
Subject: Re: [exim] Idea: Predefined macros
On Wed, 2 May 2007, Jason_Meers wrote:

> 1)option-1: "include_predefined_macros"
> A boolean which will or will not include any predefined macros. Easy to
> understand. Use it or don't use it, your call.


Chicken and egg problem. An option within the config that affects the
way the config is read. Hmm.

> 2) option-2: create_exim_runtime_configuration
> When exim starts parse exim.conf (or exim4.conf) and replace/expand any
> items that can be expanded when exim starts (including predefined
> macros) and let exim use this as its new "runtime" config. You could
> also strip out spaces, comments, linewraps etc..etc..


There is no concept of "exim starts". So it doesn't know when to do this
transformation.

You have always been able to write your own "edit the Exim config"
script (compare visudo and similar) that allows you to edit the file,
then transforms it in any way you like, possibly even tests it (there's
a thought :-) and then installs the result for Exim to use.

There are plenty of Unix tools to help you do this. I'm afraid I don't
see why Exim should invent another one.


On Wed, 2 May 2007, Stefan Klatt wrote:

> What about a precompiled configfile for the next version?


Back to Sendmail circa 1980?


On Thu, 3 May 2007, Nigel Metheringham wrote:

> The thing we could, of course, take from sendmail, is to do macro
> expansion outside the MTA - ie pre-process a macro-ised config file
> into the real config file using the macro preprocessor of choice (in
> my case not M4). You can then make things arbitrarily complex
> without a run-time hit.


... as I suggested above.


-- 
Philip Hazel            University of Cambridge Computing Service
Get the Exim 4 book:    http://www.uit.co.uk/exim-book