Commiting integration of Site Wide Categories into Weblogger. While
implementing this I've also fixed numerous random bugs.
Some comments off the top of my head regarding this implementation:
* Weblogger currently doesn't take advantage of nested categories. You
can use trees that are nested but categories in those trees are
treated as if they were all flat.
* I've provided a migration script from old to new categories. The
script just copies data and doesn't delete anything. It is written
in Tcl so that it can take advantage of the APIs.
* I left the legacy categories in system. There are several reasons
for that:
- Site-Wide categories don't have short names and thus speaking
URLs are not implemented. Some people might prefer to keep
speaking URLs, especially if they don't want to break them
after migration
- Blogger-specific categories are simpler and thus easier to use.
- Having both solutions available for a while makes transition less
painful.
* I had lots of problems with Oracle port. At first I thought just
that it is slightly instable because we are working on HEAD and
categories are in flux... Only after having fixed a lot of bugs I
realized that LEGACY CATEGOIRIES NEVER WORKED IN ORACLE. At that
point it was easier to make them actually work in oracle :-)
* Actually it seems that the whole Weblogger never worked in Oracle, I
was fixing bugs such as broken filtering by date (because Oracle's
trunc() uses different format strings from PostgreSQL's date_trunc()
etc. etc.
* Juggling pieces of Tcl from .tcl to .xql (via variable and command
substitution) and pieces of SQL from .xql to .tcl (via db_map) was
fun :-)
* Implementing nested multirows (to show all categories one object is
in), in combination with included templates thought me a lot about
the templating system. One of the lessons: <multirow name="@foo@">
with variable could actually work if a bunch of bugs with variable
substitution were fixed in templating system. Until then using:
template::multirow -local -ulevel 1 upvar $foo myfoo will be
necessary.
* Some extensions for db_multirow, <multiple> and friends to support
grouping and tables-within-tables would be really useful. I didn't
dare do such large-scale hacks on db_multirow
* one-entry{tcl,adp} should be replaced with blog{tcl,adp} - after all
getting one entry is just a special case of getting many entries.
