Lambda is a dialect of LISP that you can write on mobile!
Lambda allows you to write simple LISP expressions using all the primitive mathematical operators (+, -, *, /), comparison operators (>, >=, <, <=, =), conditional (cond), logical operators (or, and), etc.
You can also define variables and methods, including recursion.
Full syntax at: https://github.com/reddragon/lambda/blob/master/README.md