DuckDuckGo is a search engine that accepts plugins contributed by the community to provide "instant answers" for certain domain-specific queries. See DuckDuckHack.com for more information about developing plugins for DuckDuckGo.I created a plugin called tcl_ref which displays syntax synopses and command descriptions from the Tcl/Tk 8.5 manual pages in response to queries that mention "Tcl" and a recognized command name.Here is an example. A query for "Tcl upvar" returns this syntax summary, which links directly to the corresponding manual page:(Other normal search results appear below this summary.)
The plugin is a first effort. I invite anyone who is interested in improving the plugin to fork it on GitHub and submit the improvements to DuckDuckGo.