Working on Lisp-Like Parser
One of the many potential next projects for me might be a greeks server - like I've worked on in the past. The difference here is that it's targeted to me a lot more flexible than the old MarketMash system - this one is going to allow for the clients to give it "mutations" to the center state so their numbers can be as good, or bad, as they want. I've fiddled with a lot of different schemes for specifying this kind of mutation - including muParser. But those don't seem right in this context.
The choice for this seems to be a lisp-like language that is in use in some other projects in The Shop, and it would be a natural fit to have a C++ version of this for any C++-based projects. Right now, the only version is a Java-based one, and while that's nice, it's also heavily customized to the application it sits in. What I'm looking for is a simple parser that can have variables, constants, functions all added to it - augmenting a nice set of default capabilities so the user can make of it what they want.
The language isn't really hard. The expressions are really pretty simple:
(set boo 5) (+ boo 10) (* 12 5 3) (avg (min boo 5) (max boo 5))
stuff like that. Each expression has a function as the first argument, and then a series of items - which can be values or other expressions. I've just decided to make the Item a base class, subclass Value and Expression, and then start the coding.
Today was all the parsing of the input text, and it's pretty nicely compact. I'm pleased with the way it's looking. Tomorrow is the functions, etc.