IBaseScriptingInterface

This interface is what you inherit from if you want to make a new language interface.

Here is how it looks like in the code:

public/qscript/qscript_language.h

abstract_class IBaseScriptingInterface : public CBaseAppSystem<IAppSystem>
{
public:
    virtual InitReturnVal_t Init() = 0;
    virtual void Initialize() = 0;
    virtual bool Connect(CreateInterfaceFn factory) = 0;
    virtual void Shutdown() = 0;
    virtual void ImportModules(CUtlVector<QModule*>* modules) = 0;
    virtual QInstance* LoadMod(QMod* mod, const char* path) = 0;
    virtual QReturn CallCallback(QCallback* callback, QArgs* args) = 0;
};

Here is a rundown of all the functions.

Init

Gets called after Connect(). I suggest that you dont do anything here and just return INIT_OK.

Initialize

Unused.

Connect

Gets called before anything else. This is where you connect everything you need.

Shutdown

Gets called upon shutdown.

ImportModules

Gets called when QScript has finished importing all modules. (During PostInit)

LoadMod

Loads a single file and gets the mod its from. Must return a QInstance or 0 if the path's file extension doesnt match the language.

CallCallback

Calls the QCallback with the specified QArgs. You mustnt check if the QCallback is correct, it should already be.

Much more is going on under the hood. Read page 5 of the QScript Rundown