EPOC16 OPL Programming
Sat 25 Nov 2023
Psion PDAs prior to the Series 5 ran a multitasking operating system known as EPOC16, and every device with EPOC16 can run programs developed in a language called OPL, that is built right into every device.
This makes it handy for quickly automating lengthy calculations or other tasks without needing to use a computer, it has a syntax that I would best describe as BASIC-like. This is something I'm not entirely keen on, but given the vintage of the language, It's not a surprise.
I find the graphical instructions particularly interesting, as they allow for the creation of window driven GUI applications on the device itself, in 1991!
A few simple lines at the beginning transform the OPL program into an "OPA", an installable file that adds the application to the menu, With a suitable serial cable, you can even transfer a bitmap image to be used as an icon!
While I can't find a reliable source for this, I'm pretty sure that many Psion PDAs came bundled with a book on programming in the OPL language, allowing people to write helpful utilities without needing to buy a book or download documentation from the web.
I'll have some OPL applications I've written posted up here shortly, with source code of course!
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