How does psql actually implement the \d commands

Hi,

I know about the -E option to psql and did that to get the following,
which is what psql does for a \d <tablename>:

********* QUERY **********
SELECT c.oid,
  n.nspname,
  c.relname
FROM pg_catalog.pg_class c
     LEFT JOIN pg_catalog.pg_namespace n ON n.oid = c.relnamespace
WHERE pg_catalog.pg_table_is_visible(c.oid)
      AND c.relname ~ '^(personaldata)$'
ORDER BY 2, 3;
**************************

********* QUERY **********
SELECT relhasindex, relkind, relchecks, reltriggers, relhasrules
FROM pg_catalog.pg_class WHERE oid = '17408'
**************************

********* QUERY **********
SELECT a.attname,
  pg_catalog.format_type(a.atttypid, a.atttypmod),
  (SELECT substring(d.adsrc for 128) FROM pg_catalog.pg_attrdef d
   WHERE d.adrelid = a.attrelid AND d.adnum = a.attnum AND
a.atthasdef),
  a.attnotnull, a.attnum
FROM pg_catalog.pg_attribute a
WHERE a.attrelid = '17408' AND a.attnum > 0 AND NOT a.attisdropped
ORDER BY a.attnum
**************************

********* QUERY **********
SELECT c.relname FROM pg_catalog.pg_class c, pg_catalog.pg_inherits i
WHERE c.oid=i.inhparent AND i.inhrelid = '17408' ORDER BY inhseqno ASC
**************************

Now, I tried to execute these queries one at a time and they failed,
somewhat miserably.  In what order does PostgreSQL actually execute
them?  Are they implemented as sub-queries?  If so, in what order are
they executed?

Andy