Yes please :)

Check out any open issues, or dive in to add some functionality. Below I'll try to outline a few interesting parts of the code base.

GraphQLCompiler just uses the generated parsers from Antlr4 to parse the GraphQL string. The parsers are generated at compile time from EntityGraphQL.g4. The resulting Abstract Syntax Tree is then processed using the visitor pattern.

GraphQLVisitor builds on pre-generated visitors from Antlr4.

In GraphQLVisitor we visit all the tokens defined in our grammer ans process them. Basically we turn them into .Net expressions.

Example, GQL

query {
    movies {
        id name
    }
    actors { name age }
}

The final result of GraphQLVisitor is a GraphQLResultNode which just holds each top level operation, GraphQLQueryNode, GraphQLMutationNode, GraphQLSubscriptionNode or GraphQLFragmentNode.

GraphQLFragmentNode represents a defined fragment - the type it is on and the fields it selects.

GraphQLMutationNode wraps up calling the mutation with the arguments and wraps any result selection (the thing in {} after your mutation call and arguments) in a GraphQLQueryNode. Before executing the resulting selection it does some expression manipulation to have a better formed query for ORMs.

Apart from GraphQLVisitor, GraphQLQueryNode is where a majority of the magic happens. It is responsible for putting all the field expression together. It builds the Select() calls and does other expression manipulations like

• Replaces ExpressionParameters with the correct ones
• Replaces any fragment fields with the expanded field selection from the GraphQLFragmentNode
• Injects services

Not currently implemented.

The reason we build the final expression here is it is after the completion of the visitor and we no have access to fragments that may have been define after we first see them used.