Forum OpenACS Q&A: what is the best practive for extracting xml like info from variables

<delivery_address>1234 Main Street</delivery_address>
<postal_code>12345</postal_code>
<municipality>MyCity</municipality>
<region>CA</region>
<country_code>US</country_code>
<additional_text>C/O Somebody Else</additional_text>

set extract_this_item "region"

regsub -all {\t<$extract_this_item>([^\t]*)<\/$extract_this_item>\t} $value {\1} extracted_item

Look at the example on this page:
https://openacs.org/doc/openacs-4-6-3/db-api-detailed.html

In the section called Placing Column Values in Arrays and Sets

db_foreach users_select "select first_names, last_name from users" -column_set columns {
    # Now $columns is an ns_set.
    doc_body_append "<li>"
    for { set i 0 } { $i < [ns_set size $columns] } { incr i } {
        doc_body_append "[ns_set key $columns $i] is [ns_set value $columns $i]. \n"
    }
}

I know it sounds like you have been second guessed twice, but without more insight its hard to give good advice. Was your real question - "What is wrong with my regex?" :)

Here's what I mean:

<contact>

<home>
<address>
<street>1 Main St</street>
<city>Plainville</city>
<state>New York (or NY)</state>
</address>
<phone>
<number>123-4567</number>
<type>mobile</type>
</phone>
</home>

<work>
<address>
<street>1 Main St</street>
<city>Plainville</city>
<state>New York (or NY)</state>
</address>
<phone>
<number>123-4567</number>
<type>mobile</type>
</phone>
</work>

</contact>

I'm ignoring that tags don't need to balance in XML, (e.g. <number/>123-4567 could be valid )..

If it's nesting, the regex won't help with balanced tags or not, because you'll have two that match <street>xxx</street> or <street/> .. You really need to parse the tree, which is what ns_xml and similar tools are designed to do.

Of course if this package isn't meant to ever be a candidate for inclusion in the toolkit distribution feel free to do whatever you want.

Having said this ... if you insist on this approach, you really should properly parse the document using ns_xml or (preferably, since we're switching) tDOM.  Generalized XML is not parsable by simple regexps, if at some point your XML description crosses that threshold you're going to have to switch to a proper parser anyway.

I consider it to be hack-level, but for a one-time upgrade, it seems like it will do the work.

I'll ignore whether or not this is a good idea, or whether it would be better to do it with tDOM. If you're looking for the regexp, see:

http://rubick.com/openacs/acs_to_openacs