make it possible to get text from selection

Change-Id: Iafbba49f5a0ca2c75034e64eaf856d3afa41c718
Reviewed-by: Nicolas Arnaud-Cormos <nicolas@kdab.com>
use the AST to get arguments for a function call

Change-Id: Ie7ffbec02ad14a58f53924125ccc23e4e074a6e1
Reviewed-by: Nicolas Arnaud-Cormos <nicolas@kdab.com>