Eval

I am still a bit dumbfounded how to get something useful out of the Commonmark bindings. One manner of making it useful, as others showcased, is to add Yaml meta-information and a template system to a processor so I looked at the various Yaml C/C++ implementations but shied a bit away of yet another binding.

The other manner is to use Egel for metainformation or even post-processing rules. Egel-enabled Commonmark where the language plays a similar role as Javascript plays for HTML.

And, of course, that idea is somewhat neat but.. Caveats, unclear how to implement that, etc.

For one, Egel constructs are of course far more verbose than Yaml specification which is designed to be terse. Then, Egel is pure; well, mostly. How do you insert information, or even processing instructions into a document when everything is supposed to be pure? And it seems clear I need some form of `eval` but in the interpreter, so far, the evaluator makes use of a module system which in turn makes use of the runtime system. If the runtime needs to know of the evaluator I suddenly got cyclic dependencies.

This actually needs far more thought than I imagined.