OpoLua: a compiled-OPL interpreter for iOS written in Lua

An OPO (compiled OPL) interpreter written in Lua and Swift, based on the Psion Series 5 era format (ie ER5, prior to the Quartz 6.x changes). It lets you run Psion 5 programs written in OPL on any iOS device, subject to the limitations described below.

OpoLua GitHub page

If you're pining for that Psion Series 5, but don't want to deal with the hassle of owning and maintaining a real one - here's a solution if you're an iOS users. Incredibly neat, but with one limitation: only pure OPL programs work. Any program that also has native ARM code will not work.