[syslog-ng] [PATCH (3.5) 0/6]: Type hinting support

The following patchset introduces type hinting support, for mongodb and format-json for the time being, along with a couple of cleanups done prior to the introduction. The code passes unit and func tests, and is the result of a pair programming session by Balazs Scheidler <bazsi@balabit.hu> and myself, I rearranged the result and split it up into individual, mostly self-contained commits. To use type hinting with value-pairs: value-pair(pair("SOME-INTEGER" int("1234")) pair("SOME-DATETIME" datetime("$UNIXTIME"))); Simiarly, with format-json: template("$(format-json some-integer=int(1234) some-datetime=datetime($UNIXTIME))\n") Further documentation will follow later, most likely in a form of a blog post.