https://www.linkedin.com/pulse/multitiered-stack-machine-nsm-using-5gl-fifth-graph-ng-ph-d-/
http://5gl.epizy.com/nsm/fgl.html
https://github.com/udexon/SMMP
nSM simply means "a stack machine within a stack machine .... (repeat up to N times)" . It is so named because the initial implementations of nSM are coded in PHP and JavaScript, whose interpreters are themselves stack machines.
5GL (Fifth Generation Graph Language) is a stack machine programming language similar to Forth. The core stack machine is implemented in less than 50 lines of PHP and JavaScript code, and demonstrates the Inverse Shunting Yard Algorithm (ISYA), the inverse of Dijkstra's legendary Shunting Yard Algorithm (DSYA).
See demo and 5GL core in JavaScript.
We have decided not to open source it pending negotiations with investors, but you are welcome to contact the author for collaboration, which will allow you access to the source code.