Escape Mechanisms

There are several pages around the subject of the EscapeHatch. Refactoring could cut this number down a little and focus on instances or discussion, perhaps.

We already mentioned the combination of an interpreted language combined with an exec capability in EscapeHatchMechanism. What are some others? [this reminds me of AlternateHardAndSoftLayers]

A similar EscapeHatchMechanism is use of either embedding or extension. That is, the language can either be pulled into another language, so that your C program could parse Perl statements, for example, or the language could be extended with the use of libraries not written in that language, but that have some kind of interface which allows them to still be loaded and used.