On 28.11.2013 14:31, Jose wrote:
IMHO, It is worth to help this nice guy (Sandro Furieri, the author of spatialite) to discover Lua and LuaJIT :-) He currently writes insane amounts of C code to bind important libraries to SQLite as functions and even more expensive as virtual tables.A Lua binding for readosm seems the most flexible approach (readosm is from spatialite, mentioned in previous answer) http://www.gaia-gis.it/gaia-sins/readosm-1.0.0b-doxy-doc/index.html https://www.gaia-gis.it/fossil/readosm/index and then write this example in Lua (to compare to the C one) http://www.gaia-gis.it/gaia-sins/readosm-1.0.0b-doxy-doc/test_osm2_8c-example.html
For example: libxml2. He currently exposes VirtualXPath virtual table: https://www.gaia-gis.it/fossil/libspatialite/wiki?name=VirtualXPath-intro intended to be used with statements in form: select * from xpath_opera where xpath_expr = '/opera[@author = "Puccini"]/@title'which is OK, but for the people paying rents with datapocessing it is well known, that there regularly arises the need of one more table: VirtualXPath2 for:
select attr_xpath('./@title') title, attr_xpath('count(./part)') parts
from xpath_opera
where node_xpath_expr = '/opera[@author = "Puccini"]'
which would cost Sandro even more than the former.
I have added to my "some good day" TODO :-(, to propose patch for
spatialite reimplementing libxml2 vtables via LuaJIT.
Kind Regards, Alek