Finally, if you know on which TAP server the service is located, you can query a table directly from the command line and select the output format, e.g.:
wget "http://voparis-tap-planeto.obspm.fr/tap/sync?REQUEST=doQuery&LANG=ADQL&QUERY=SELECT * FROM exoplanet.epn_core WHERE "star_name" LIKE '%GJ 357%' &FORMAT=json"
(will retrieve description of exoplanets around star GJ 357. We're passing a TAP query via wget, which contains an ADQL query after the QUERY parameter. This mechanism applies to all EPN-TAP services. Available output formats depend on the server).
The most helpful IDL libraries in this context are NASA's Astron library, and possibly SSW.