Add direct JSON return of search results

[lehenbauer]

Using yajl or whatever, add a direct JSON return capability. It can be a direct C-to-C thing and since type inspection from C is trivial and fast we can generate the JSON with fidelity. The Tcl interpreter wouldn't even need to be invoked for each match.

Something like... $table search -compare [list [list > clock $val]] -json varName

...to get the json into a var. You might want a -jsonfp or something, to write directly to a file handle or socket.