Implement Ruby-only parser for Expressir (was: crashing nearly on every run on Ruby 3.2.2)

[ronaldtse]

We need to replace this with a Ruby-only solution.

[ronaldtse]

The EXPRESS grammar is located here:

• https://github.com/lutaml/express-grammar

The task here is to develop a parser (using the pure-Ruby Parslet gem) to parse the EXPRESS syntax, then link each EXPRESS node back to the objects provided in this library (expressir).

Then we can get rid of the "rice" interface which requires C++ compilation.

It was a terrible (i.e. very terrible) mistake to use ANTLR to generate the parser, which has caused us much agony and costs in maintaining the parser.