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Re: Parsing efficiency? - why not 'compile'????

• To: "Alaric B. Snell" <alaric@a...>, xml-dev@l...
• Subject: Re: Parsing efficiency? - why not 'compile'????
• From: Elliotte Rusty Harold <elharo@m...>
• Date: Thu, 27 Feb 2003 10:26:21 -0500
• In-reply-to: <E18oPCa-0001s1-00@c...>
• References: <OF047F14BF.0A3C2919-ONCA256CD8.00031C17@f...><20030227073457.2C45F5542@c...><p04330106ba83be615336@[192.168.254.4]><E18oPCa-0001s1-00@c...>

At 2:39 PM +0000 2/27/03, Alaric B. Snell wrote:

>No, no, relax; in the scheme I suggested, it uses the type information as
>*advisory* data on how to encode stuff. It could ignore it all and just put
>everything in as strings. This is what people refer to as a "Schema-aware
>compressor".

I'm not sure what you're suggesting is what Robin's suggesting. Right 
now I'm very confused (not that unusual or even unproductive a state 
to be in, though :-)

Type-awareness strikes me as fundamentally dangerous, especially in 
this sort of scheme. Yes, it could encode everything as strings but 
given that it doesn't, how do I decode? Do I have to have the schema 
handy? or is the type information bundled into the binary file?

Also, how are elements like these encoded?

<quantity type="xsd:int">000017</quantity>
<quantity type="xsd:int">17.00000</quantity>
<quantity type="xsd:int">17.5</quantity>
<quantity type="xsd:int">two</quantity>
<quantity type="xsd:int">2 and not a fnord</quantity>
<quantity type="xsd:int>Cheesy Poofs</quantity>

I expect any plausible binary compression scheme to be lossless with 
respect to the infoset, not the PSVI mind you but the I. I don't 
expect to lose any significant data just because:

1. The data is invalid
2. I happen to use a different schema for decoding than you used for encoding

If the binary compression fails these tests, I cry shenanigans on you. :-)
-- 

+-----------------------+------------------------+-------------------+
| Elliotte Rusty Harold | elharo@m... | Writer/Programmer |
+-----------------------+------------------------+-------------------+
|           Processing XML with Java (Addison-Wesley, 2002)          |
|              http://www.cafeconleche.org/books/xmljava             |
| http://www.amazon.com/exec/obidos/ISBN%3D0201771861/cafeaulaitA  |
+----------------------------------+---------------------------------+
|  Read Cafe au Lait for Java News:  http://www.cafeaulait.org/      |
|  Read Cafe con Leche for XML News: http://www.cafeconleche.org/    |
+----------------------------------+---------------------------------+

• Follow-Ups:
  • Re: Parsing efficiency? - why not 'compile'????
    • From: Dennis Sosnoski <dms@s...>
  • Re: Parsing efficiency? - why not 'compile'????
    • From: "Alaric B. Snell" <alaric@a...>

• References:
  • Parsing efficiency? - why not 'compile'????
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  • Re: Parsing efficiency? - why not 'compile'????
    • From: Alaric Snell <alaric@a...>
  • Re: Parsing efficiency? - why not 'compile'????
    • From: Elliotte Rusty Harold <elharo@m...>
  • Re: Parsing efficiency? - why not 'compile'????
    • From: "Alaric B. Snell" <alaric@a...>

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