richthegeek / ajs

Javascript evaluator with seamless asynchronous handling

We have a reason, and execution environment, for code that looks like this:

user.devices.sessions.actions.filter(...)

Which in reality actually has several layers of asynchronous code:

• the devices are looked up in the database
• then the sessions are looked up in the database, for all devices
• then the actions are retrieved from all sessions and it's filtered

The way it's done at the moment is to throw promises and repeatedly re-run it until no promises are thrown.

This is crazy, but it works (https://github.com/richthegeek/node-deferred-object)

However, whilst it is somewhat-efficient (<1ms most of the time) it causes a bunch of problems (uncaught promises on edge cases) and generally is a bit of a hassle.

This is an attempt to make the code run only once, with breaks for asyncronous stuff to resolve.

The first step of this, however, is simply to make the javascript compile.

Frankly, this is almost definitely a very bad idea. But I'm doing it anyway.

ajs's Issues

Implement a context class stack

Currently contexts are passed around on objects in a rubbish manner. This isn't an issue yet because I've not done much with functions, but it will quickly become untenable.

Solution is to implement a Context class which has a pointer to it's parent context. The context class has several methods (currently in index.coffee):

1. Context::constructor(Context) - instantiates a new context pointing to the passed Context as it's parent
2. Context::get(key, callback) - iterates through to parent until it exists, and returns it when it does
3. Context::set(key, value, callback) - iterates through to parent until it is found and sets it there, else sets it on the current context.
4. Context::unset(key, callback) - like Context::set but issues a delete when found.

Each node has a context as before, but this stop certain classes of bugs before they occur.