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> The author also doesn’t suggest what should be used instead to encode structured data, or perhaps more importantly what should have been used to encode graph like things such as map/lists/objects in the 2000’s.

That’s easy: S-expressions. Steve Yegge wrote about this in 2005: https://sites.google.com/site/steveyegge2/the-emacs-problem

Would you rather have:

    <?xml version="1.0" encoding="utf-8" standalone="no"?>
    <!DOCTYPE log SYSTEM "logger.dtd">
    <log>
    <record>
      <date>2005-02-21T18:57:39</date>
      <millis>1109041059800</millis>
      <sequence>1</sequence>
      <logger></logger>
      <level>SEVERE</level>
      <class>java.util.logging.LogManager$RootLogger</class>
      <method>log</method>
      <thread>10</thread>
      <message>A very very bad thing has happened!</message>
      <exception>
        <message>java.lang.Exception</message>
        <frame>
          <class>logtest</class>
          <method>main</method>
          <line>30</line>
        </frame>
      </exception>
    </record>
    </log>
or:

    (log
     '(record
       (date "2005-02-21T18:57:39")
       (millis 1109041059800)
       (sequence 1)
       (logger nil)
       (level 'SEVERE)
       (class "java.util.logging.LogManager$RootLogger")
       (method 'log)
       (thread 10)
       (message "A very very bad thing has happened!")
       (exception
        (message "java.lang.Exception")
        (frame
         (class "logtest")
         (method 'main)
         (line 30)))))


I have no strong preference for either, so long as both of them convey the structured information I need.

Although tbh I'm preferring the XML in your example due to the lack of random quotes - why does (record need a quote, but (log doesn't?

The XML seems a lot more consistent.


The example seems pretty weird. If it's just data there shouldn't be any quotes at all. The only purpose of quoting is to prevent evaluation, so I guess the idea must be that `log` is a function call to be evaluated, but then the example isn't even the same thing as the XML version (and there are still nested quotes inside the already quoted record).


You'll want XML as soon as it exceeds one screenful :) And this XML is, well, "musused"; it should be that:

    <log>
      <record date="2005-02-21T18:57:39" millis="1109041059800" sequence="1" level="SEVERE" class="java.util.logging.LogManager$RootLogger" method="log" thread="10" message="A very very bad thing has happened!">
        <exception id="123" message="java.lang.Exception" class="logtest" method="main" line="30" />
      </record>
    </log>
I also don't object squeezing the exception attributes into record with some prefix that would make the names unique, like that:

    <record date="2005-02-21T18:57:39" millis="1109041059800" sequence="1" level="SEVERE" class="java.util.logging.LogManager$RootLogger" method="log" thread="10" message="A very very bad thing has happened!" exc-message="java.lang.Exception" exc-class="logtest" exc-method="main" exc-line="30" />
Or, if it's possible to normalize these data, factor out the exception and other attributes and build an index of them so that they can be referenced by an ID:

    <exception id="123" message="java.lang.Exception" class="logtest" method="main" line="30" />
    
    <record ... exception-id="123" />


The S-expressions are misused too — Steve Yegge’s example, not mine. My version would have no use of QUOTE at all.


The XML version has the dtd which can be used to validate it though. I am not aware of something similar for s-expressions.


Frankly, I’d rather some form of compressed binary logs, but sure, either works if it includes a stack trace and I need it at the time! Text logs compress well anyway, they just grow larger if/when you process them later... I’m just happy to see objects as log entries instead of plaintext strings. ;)


The xml, definitely. Without lisp-specific tooling that colours/balances etc, writing 5 consecutive closing parens (and not 4 or 6) is a headache. Also I probably couldn’t choose it on its own merits - I choose what the non programmers that edit the file can use (and they sure don’t have any other editor than notepad).

Then again: I’d usually only ever choose between formats with support already on the platform/standard library, if it was just some config or small data file. If the data is core to the product then of course it might be reasonable to include a new library or even write a parser. I’m talking java and .net now mainly.




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