Joy

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Joy is a concantaive programming language, created by Manfred von Thun. It supports function-level programming by using a linked list as a stack to supply the functions with parameters. The lists in the program code are called quotations and the functions are often used as combinators. The theory of the programming language was very extensively documented by Manfred von Thun.

mjoy

mjoy is an implementation of Joy in the Lazarus IDE. It's just a subset of Joy. The idea was to introduce children to Joy programming by using a simple turtle graphic system for practice. The turtle graphic commands were formulated entirely in mjoy, with the turtle as a list object.

Example:

   init 100 -100 moveto 45 rad turn 70 move turtle draw

Joy of Postfix

Joy of Postfix is ​​an implementation of Joy in Kotlin for Android mobile phones. It is also a subset of Joy, but it is significantly richer in implemented features than mjoy. It serves as an App for Reverse-Polish-Notation fans who also want to take advantage of Joy's programmable capabilities. Documentation.

Example:

   factorial == [null] [succ] [dup pred] [*] linrec
   
   7 factorial .
   --> 5040

Implementations

• La Trobe University Zip-files
• Joy source code (GitHub-Archive)
• mjoy, an interpreter for drawings with turtle graphics (Subset of Joy)
• JoyOfPostfix/App in heise/Download in the Android Register (Subset of Joy) and the PDF-file