I've created a JSON parsing and composing library. I realize Codesys has a paid library for this, but I'm using Schneider SoMachine,and it doesn't support dynamic memory allocation, and it looks like the Codesys library uses the __NEW operator to create an array of variables. Hopefully someone finds this library useful. I've learned quite a bit from posts in this forum, and I guess this is my way of contributing back to the community.
There's an example program in the library, and commenting throughout the various functions.
I've tested this with a number of different JSON strings, but there's no guarantee that it's 100% bug free. My testing environment was Schneider SoMachine 4.3, with M241/M251 PLCs. Comment below to contribute ideas, request changes, or report a bug.
EDIT: version 22.214.171.124, fixes a few bugs
UPDATE: this package has been added to the Codesys Forge https://forge.codesys.com/lib/pro-json/home/Home/
Thanks to Ingo for the assistance with that.