What makes a good extension language?

&lsquo;Scripting languages are designed for gluing&rsquo;, wrote John Ousterhout, the&#xA;creator of Tcl, in 1998. 1 What Ousterhout had in mind&#xA;was writing an application in a scripting language and having it delegate&#xA;certain functions to components written in system programming languages. A&#xA;similar idea inspired the wrapper generator SWIG ,&#xA;developed for scientific computing. 2…