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Re: [ddlm-group] New syntax: 'marker' characters

I am away at a meeting.  I'll try to comment on all this when I
get back, if you all have not resolved it. -- Herbert

=====================================================
  Herbert J. Bernstein, Professor of Computer Science
    Dowling College, Kramer Science Center, KSC 121
         Idle Hour Blvd, Oakdale, NY, 11769

                  +1-631-244-3035
                  [email protected]
=====================================================

On Thu, 5 Nov 2009, James Hester wrote:

> Hi Joe and others: based on what Joe reports, it would seem pointless
> to add markers to the syntax, as an application can simply do a first
> quick non-tokenising run through a CIF file and create an index for
> itself if it desires efficient data extraction.
>
> I'll take up the theme of ordering elsewhere.
>
> James.
>
> On Thu, Nov 5, 2009 at 5:53 AM, Joe Krahn <[email protected]> wrote:
>
>> I use a regexp that properly handles all comments and quoting types in
>> CIF1, so it does not just search for the 'data_' sub-string.
>>
>> I am actually surprised that it could parse so quickly. However, this
>> requires parsing characters without tokenizing them; a data block is a
>> single regexp. A normal CIF parser may not be designed to parse without
>> tokenizing and storing values, so it may take some redesign to get the
>> same performance even in a compiled program.
>>
>> Of course, there is no reason why a given CIF implementation could not
>> use comments as hints for faster parsing. Even with the above argument
>> that fast parsing is possible, a large network-mounted file could go
>> slow just reading the intervening file data. However, putting the hints
>> in comments means that it does not need to be part of the CIF spec.
>>
>> Ordering hints are a bit different, because they affect more than just
>> comments. Currently, order is supposed to be irrelevant, so you could
>> claim that it is also just a performance hint. I have always thought
>> that a canonical order is useful. Most CIF software writes out "pretty"
>> formatted text because organization is useful when being viewed by a
>> human. Herbert's suggestion is to make preferred ordering an integral
>> part of the DDL, but avoid incorporating ordering rules into the CIF
>> syntax. Then, people that want ordering rules can use them, but it avoid
>> complicating the CIF spec.
>>
>> Joe Krahn
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>>
>
>
>
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