Tuesday, May 22, 2012

Breaking Ground

The documentation has gotten to a point where the things that are well known are done, and the things that are not will not get much better writing documentation. So I have broken ground on (yet another) iteration of the language. The implementation focus for this one will be testability and doing only what the requirements specify. I am also going to focus on stable releases; not that anyone downloads them... That said, I've completed the first release of the new iteration:


The exe is a simple command line interface for the parser. Pass in a filename and see if it parses correctly. Error messages exist, but are not very good in a number of places. That and there are only a few places where parsing can fail in Tangent before the type interpretation occurs.

One departure during this iteration is that I am hand-rolling my own lexer/parser for the language. Why? Yes, it's because I suck. Oh, why did I choose to do it you mean? Glad you asked.

In the previous few iterations I used the parsing framework to do the language parsing. It was good enough. Unfortunately, its output was a generic untyped syntax tree. A good amount of busy-work (and errors) in the previous iterations was walking the list, verifying children and transforming it into something usable. By rolling a specific parser, the result is tightly coupled to the language meaning everything I expect to be there is there. All the different pieces of the syntax have good names and correct types. Ideally this will provide cleaner code where the parsing results are being consumed, making the implementation less complicated and thus more likely to advance successfully.