A small functional language interpreter similar to Haskell implemented in python and ANTLR4, done just for self-learning.

a = 1;

f(x): x + 1;

f(x): x ? 1 : 0;

a = {x=1;x};

a = [1,2,3];

All functions return a value, even builtin functions. Assignment returns always 1. print returns always 1. One difference with Haskell is there is no pattern matching.

• +, -, *, /, **: arithmetic operators
• |, &, ^: bitwise/boolean operators
• ~: 2 complement.
• !: logical negation.
• $: convert a list into parameters for a function.
• >,>=,<,<=,==: comparation.
• (expr) ? (expr1) : (expr2) : if/else
• #: start comment line.

• split(list) returns the list splitted into head and tail
• map(func, list) returns the mapping of a function over a list
• print(...) prints parameters

x(a,b): a + b; 
print(x(1,2));

fib(x): x <= 1 ? x : (fib(x-1)+fib(x-2));
print(fib(5),fib(6),fib(7),fib(8));

printlines(x): 
    x ? { h, t = split(x) ; print(x) ; printlines(x) }
      : 1;

items=[1,2,3,4,5,6];
printlines(items);

# passing list as parameters
do_something(a,b,c,d,e,f,g): 1

do_something($items);

x(a,b): a + b;
z(f,a,b): f(a,b);
print("function as first class object:",z(x,1,2));

max(x): x 
    ? { h,t=split(x); m=max(t); h > m ? h : m } 
    : 0;

sum(x) : x ? {h,t=split(x); h+sum(t)} : 0;

print(max(items));
print(sum(items));