Miller domain-specific languages

These exist for Miller's put and filter functions. The grammars are not at all profound: just parsing 101 as familiar from an introductory compilers course. I use lex and lemon rather than lex and yacc: I find Lemon far more transparent.

Concrete syntax trees (CSTs) are embodied in the lex/lemon files. Abstract syntax trees (ASTs) are in the Miller containers directory.