Generating config stuff from single source

We are currently maintaining information about configuration parameters
in at least three places: the documentation, guc.c, and
postgresql.conf.sample. I would like to generate these from a single
source. Computationally, this is not very challenging, it's just a bit
of work. I imagine as the source an XML file with a custom schema; see
below for an example. I think this is the best source format because
it allows integrating the DocBook-formatted descriptions without too
much trouble and it allows for file format validation. An alternative
might be m4 but that would not offer these features. To process this
we'd use XSLT stylesheets run through xsltproc. We'd run this part
during the tarball building phase, so users would not need it.
Obviously, all of this will need some fine-tuning, but can we agree on
this general direction?

<parameters>
<group>
<title>Query Tuning</title>

<subgroup>
<title>Planer Method Configuration</title>

<parameter>
<name>enable_hashagg</name>
<context>userset</context>
<shortdesc>Enables the planner's use of hashed aggregation
plans.</shortdesc>
<longdesc>blah</longdesc>
<vartype>bool</vartype>
<variable>enable_hashagg</variable>
<resetval>true</resetval>
<min>...</min>
<max>...</max>
<assignhook>...</assignhook>
<showhook>...</showhook>
</parameter>

</subgroup>
</group>
</parameters>

--
Peter Eisentraut
http://developer.postgresql.org/~petere/