RoundTripping

Round Tripping

Mt4 can call Python, but Python can't call Mt4. So we need to establish a round-trip from Mt4 that looks to see if there is anything that Python wants it to do.

The way we do this is to make a Queue object from the Python library Queue and push anything Python wants done onto the Queue in Python. Then put a timer event in your Mt4 expert that fires periodically (like even 10 seconds), and calls the Python code to pop the work off the queue.

However, Mt4 does not have an eval command to handle arbitrary strings to be executed. So we wrote the zOTLibProcessCmd` in the OTMql4Lib project (OTLibProcessCmd.mq4) that approximates what should be Eval in Mt4.

Depending on how you push things onto the queue, you may want to take the result of zOTLibProcessCmd and distribute it via RabbitMQ.

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