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Subject: Re: Array data in db files?
From: Benjamin Franksen <[email protected]>
To: <[email protected]>, <[email protected]>
Date: Mon, 25 Aug 2014 20:14:10 +0200
Am Montag, 25. August 2014, 06:18:12 schrieb Michael Davidsaver:
> On 08/24/2014 12:42 PM, Benjamin Franksen wrote:
> > ...
> > 
> > The db/dbd syntax can be generalized to a very simple syntax that
> > basically
> > 
> > recognizes one kind of item:
> >   item ::= keyword "(" arg "," ... ")" [ "{" item ... "}" ]
> 
> This would be ideal were it not for three things: embedded C code '%',
> statements like 'addpath' which don't have '(', and break point tables
> (just numbers).

(...yea, the small print...)

> What I have is the following where a 'value' is either a keyword, quoted
> string, or number. "%.*$" is lexed as 'code'.
> 
> item ::= value '(' value ',' ... ')' [ '{' item ... '}' ]
> 
>         | value value
>         | code
> 
> Break point table entries and "addpath" are parsed as "value value".
> 
> This definition parses all the existing dbd files I've tried so far from
> base and synapps.
> 
> > ...
> > The main point is that the syntax is now easily extensible by adding a new
> > keyword and the corresponding function in the table. Unknown keywords
> > (together with the item they introduce) are ignored (or optionally give
> > warning), so that future extensions never break existing parsers.
> 
> Yup, this is the goal.

Cool!

Cheers
Ben

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References:
Array data in db files? Ralph Lange
Re: Array data in db files? Benjamin Franksen
Re: Array data in db files? Michael Davidsaver

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