You will want to have a look at Chapter 17, Template Driven Code Generation, in the "Advanced Perl Programming" book. This uses a C like language to specify object models to generate C++ headers and SQL statements.

The classical reference for this type of stuff is of course: Little Languages. In: More Programming Pearls: Confessions of a Coder. John Bentley. Association for Computing Machinery, 1988. (BTW, if anyone out there has a copy of this book that he wants to sell, I would really, really like to buy it!)

Another really easy syntax to set things like this up would be a LISP like (prefix) syntax (e.g., like Excel functions do it). You can easily parse this stuff and implement it by functions that you call from a central dispatcher.

As for verbosity, it seems that all XML based stuff is incredibly verbose, so I doubt that this is such a good choice. Besides that, people who can write XML will be able to handle a CGI form, too. You will need a syntax simpler than that, IMHO. As mentioned above, I really like this Excel function like syntax - it is easy to implement, and users have got used to it.

Christian Lemburg
Brainbench MVP for Perl
http://www.brainbench.com

Darn! I was just trying to do that!

You might remember one of my pet projects, a Module Reviews (again!)

So I was just trying to write a simple CGI that would do this, and I came up with this simple way to write a template to generate the form:

<conf>
  <category id="usage" html="select" multiple="multiple">
    <name>Usage</usage>
    <option id="read">Read Docs</option>
    <option id="tested">Tested</option>
    <option id="rejected">Rejected</option>
    <option id="used">Used</>
    <option id="used_a_lot">Used a lot</option>
  </category>
  <category id="quality" html="radio" type="number" range="0-5">
    <name>Quality</name>
  </category>
  <category id="documentation" html="radio" type="number" range="0-5">
    <nameDocumentaion></name>
  </category>
  <category id="support" html="radio" type="number" range="0-5" na="ye
+s">
    <name>Support</name>
  </category>
</conf>
[download]

Now I plan to use this config file to both generate the input form and then to drive the generation of the XML created when the form is used.

Does this makes sense? And is this close to what you want to do?

I'll have the code later, sorry, you just caught me in the act of writing it ;--(

Yes, this is very close to what I want to do. Although data for multiple selects and the like could potentially be pulled from database tables. The big question is, how will you translate that to html? I'd like to allow them to specify a font or whatever, but in doing that it gets so close to being the actual html form, that I may as well have them write it in html :). Will you parse it yourself and translate? I'd like to know if there is a way to do that without parsing it completely yourself.

Just for the sake of filling up vroom's database :), let me show you what I have so far (P.S. this describes a form, but it also tries to describe a table structure, both of which refer to adding an entry which is a computer system). This was done with the intent of parsing it myself to produce appropriate html, but again, if there's a way that I could rewrite/retag everything and use some module to produce the output, I'd love that.

<?xml version="1.0" standalone="yes"?>

<!-- Everyone gets an id for free, you must have a unique "subject" ro
+w!!! -->
<!-- i.e. for every addition to a type, an id will be assigned -->
<!-- i.e. everything must have a row named subject (VARCHAR(128) max) 
+-->
<!-- which will contain the hostname or whatever you like, but it -->
<!-- _must_ be named "subject" -->

<!-- Stuff to think about -->
<!-- <macro type="sql">SELECT * from foo</macro> -->
<!-- <macro type="perl">sub { print 4 * 50 }</macro> -->
<!-- select id,subject from (whatever) where something="stuff" -->
<!-- <target>id:subect:something="stuff"</target> ? -->
<!-- <name>file</name><datatype>blob</datatype><style>file_upload</sty
+le> -->

<!-- ********** START SYSTEM DEFINITION ********** -->
<form> 
    <name>System</name>
    <post_notes_to>1</post_notes_to>
    <email_notes>1</email_notes>
    <row> 
        <element>
            <label>Hostname</label>
            <name>subject</name>
            <required>1</required>
            <validchars>[\w\.-_]+</validchars>
            <datatype>varchar</datatype>
            <size>25</size>
        </element>
    </row>
    <row>
        <element>
            <label>Vendor/Model</label>
            <name>sysdesc</name>
            <required>1</required>
            <validchars>[\w\.-_]+</validchars>
            <datatype>varchar</datatype>
            <size>64</size>
            <default>Sun UE6500</default>
            <instructions>(i.e. Sun UE6500)</instructions>
        </element>
    </row>
    <row>
        <element>
            <label>Serial#</label>
            <name>serialnum</name>
            <required>0</required>
            <validchars>[\w\.-_:]+</validchars>
            <datatype>varchar</datatype>
            <size>32</size>
        </element>
    </row>
    <row>
        <element>
            <label>Maint Contract</label>
            <name>maint</name>
            <required>0</required>
            <datatype>varchar</datatype>
            <style>pulldown</style>
            <title>Select Contract...</title>
            <info_from>Maintenance</info_from>
            <target>id:subject</target>
        </element>
    </row>
    <row>
        <element>
            <label>Mac Address</label>
            <name>mac</name>
            <required>0</required>
            <validchars>[\w:]+</validchars>
            <datatype>varchar</datatype>
            <size>32</size>
        </element>
    </row>
    <row>
        <element>
            <label>OS Level</label>
            <name>oslevel</name>
            <required>0</required>
            <validchars>[\w\.]+</validchars>
            <datatype>varchar</datatype>
            <size>32</size>
            <default>SunOS 5.8</default>
        </element>
    </row>
    <row>
        <element>
            <label>IP Address</label>
            <name>ipaddr1</name>
            <required>0</required>
            <validchars>[\d/:\.]+</validchars>
            <datatype>varchar</datatype>
            <size>32</size>
        </element>
    </row>
    <row>
        <element>
            <label>Contacts</label>
            <name>icontacts</name>
            <required>0</required>
            <datatype>varchar</datatype>
            <style>multiple</style>
            <size>3</size>
            <title>==Internal Contacts==</title>
            <info_from>Internal Contacts</info_from>
            <target>id:subject</target>
        </element>
        <element>
            <name>vcontacts</name>
            <required>0</required>
            <datatype>varchar</datatype>
            <style>multiple</style>
            <size>3</size>
            <title>==Vendor Contacts==</title>
            <info_from>Vendor Contacts</info_from>
            <target>id:subject</target>
        </element>
    </row>
    <row>
        <element>
            <label>Description</label>
            <name>description</name>
            <required>0</required>
            <datatype>text</datatype>
            <style>textarea</style>
            <size>45w:10h</size>
        </element>
    </row>
    <row>
        <element>
            <label>Last Modified</label>
            <name>date</name>
            <required>0</required>
            <datatype>date</datatype>
        </element>
    </row>
</form>
[download]

I'll show you the code as soon as it's written! I have just one comment on the format you're using: consideringyou are doing really strict typing of the data, you might want to have a look at the W3C's XML Schemas, which (supposedly, I never actually read the spec) cover that feature quite well.

As for parsing the data I'll use as usual XML::Twig to generate the form, and probably a combo of CGI::XMLform to get the data and XML::Twig to create the initial data for a module and to update it's record from the CGI, as it makes it pretty easy to update just a record with a given id (but of course I am partial to XML::Twig, especially as I can always fix it if there is any problem ;--)

More on that later...