I created a Joy interpreter for Android in Kotlin.
If you don’t know Joy yet, it is an extremely simple Postfix language for programming your own functions and its execution in a pipeline - an RPN calculator, so to speak.
It uses a linked list for the parameter stack that is passed on between the functions. As a result, Joy can be signed as a real functional programming language and this variant is often with a monade at the end of a sequence.
There are two sources from where the app and the PDF can be downloaded.
homepage Where there are also many information about the app.
And Concatenative.org where heise download is also given.
I wish you a lot of fun and joy with the app,
metazip