Feature parquet extract module

di/pqx/VERSION

@@ -0,0 +1 @@
+0.1.0

di/pqx/init.q

@@ -0,0 +1,20 @@
+/ KDB-X Parquet extract module to save kdb+ data to parquet storage convention
+
+arrow:use`kx.arrow
+pq:use`kx.pq
+pqt:use`kx.pq.t
+
+\l ::pqx.q
+
+/ module version, read from the VERSION file (one plain-text file to bump per release). read
+/ module-relative at load (`:::` resolves to di/pqx) and BEFORE export, since export:([...])
+/ evaluates each name; version stays in the export so di.depcheck reads it from the export dict.
+/ trim, and fail LOUD on a missing/unreadable/empty VERSION, rather than a bare `first read0`:
+/ a raw OS error names no module, and an empty or whitespace-padded value is worse than an error -
+/ di.depcheck compares versions as STRINGS, so padding silently breaks the comparison and an empty
+/ value reads as "exports no version", failing every dependent module's check for a reason that
+/ points nowhere near the real cause.
+version:@[{trim first read0 x};`:::VERSION;{'"di.pqx: VERSION file missing or unreadable"}];
+if[0=count version;'"di.pqx: VERSION file is empty"];
+
+export:([init;extract;getmanifest;checkandconvertcols;estimate;plan;writefile;readfile;tryfn;buildvirtualtable;checkvirtuallevels;checkvirtualtypes;version])