lambda.js

// LAMBDA WORLD ================================================================
zero = p => x => x;
one = p => x => p(x);
inc = n => p => x => p(n(p)(x));
two = inc(one);
three = inc(two);
add = n => m => m(inc)(n);
five = add(two)(three);
mul = n => m => m(add(n))(zero);
fifeteen = mul(three)(five);
ten = add(five)(five);
hundred = mul(ten)(ten);
pair = x => y => f => f(x)(y);
left = p => p(x => y => x);
right = p => p(x => y => y);
p1 = pair(three)(five);
lp1 = left(p1);
rp1 = right(p1);
nextp = p => pair(right(p))(inc(right(p)));
dec = n => left(n(nextp)(pair(zero)(zero)));
ninetynine = dec(hundred);
sub = n => m => m(dec)(n);
eightyfive = sub(hundred)(fifeteen);
np1 = nextp(p1);
ltrue = x => y => x;
lfalse = x => y => y;
not = b => b(lfalse)(ltrue);
and = a => b => a(b(ltrue)(lfalse))(lfalse);
or = a => b => a(ltrue)(b(ltrue)(lfalse));
iszero = n => n(x => lfalse)(ltrue);
le = n => m => iszero(sub(n)(m));
ge = n => m => iszero(sub(m)(n));
eq = n => m => and(le(n)(m))(ge(n)(m));
empty = pair(lfalse)(lfalse);
shift = a => n => pair(ltrue)(pair(n)(a));
arr0 = shift(shift(empty)(one))(two);
//==============================================================================

// printing
function pdoc(x) { document.body.innerHTML += x + "<br>";  }
function pcon(x) { console.log(x);  }
var p = pcon;
function to_i(n) { return n(x => x + 1)(0); }
function pi(n) { p(to_i(n)); }
function to_b(b) { return b(true)(false); }
function pb(n) { p(to_b(n)); }
// (ltrue, (one, (lfalse, lfalse)))
function to_a(a, res) {
    res = res || [];
    if (to_b(left(a))) {
        res.push(to_i(left(right(a))));
        to_a(right(right(a)), res);
    }
    return res;
}
function pa(a) { p(to_a(a)); }

pb(ge(one)(two))
pb(eq(one)(two))
pb(eq(one)(one))
pa(arr1);