Develop Parser for Custom Software

In need of building a simple parser for our e-commerce custom software. It will run as command-line and will parse input using a well-defined grammar and tree of possibilities, validate the input for correctness, identify syntax / semantic errors and generate a set of instructions to be executed, i.e. call web service. There are about 40-50 different possibilities, using 5 categories of actions. May start with a simple trial project and assign full scope afterwards. Access to skpe or gchat is essential.