Functional programming language for Python programmers and friends
Just for you, and this time in the Pythonesque rendering.
module main: import std (range) import std.io (printf, IO) # print the Fahrenheit-Celcius table for fahr = 0, 20, ..., 300 function main(mutable IO io): Int lower = 0 # lower bound Int upper = 300 # upper bound Int step = 20 # step for Int fahr in range(lower, upper, step): Double celcius = 5 * (fahr - 32) / 9 std.io.printf(io, "%3d\t%6.1f\n", fahr, celcius)
It does not really look like it, but this language is purely functional. It represents side effects using unique types. If you declare a mutable parameter, you basically declare a unique input parameter and a unique output parameter.
I’m also giving you a list implementation
module std.container.list: ## The standard singly-linked list type type List[E]: Nil ## empty list Node: E value ## current value List[E] next ## remaining list
And yes, both languages should be able to be represented using the same abstract syntax tree. The only change is the replacement of the opening curly brace by a colon, the removal of the closing curly bracket and semicolons, the replacement of C-style comments with Python-style comments and the requirement of indentation; oh and the for statement gets a bit lighter as well.