Constant STDLIB

pub const STDLIB: &'static str = "
% ===== Standard library

eq(A, A).

% All the following are susceptible to going out of bounds on i64 values.

isLess(fraction(Fn, Fd), fraction(Gn, Gd)) :- isLess(mul(Fn, Gd), mul(Gn, Fd)).
is(fraction(Fn, Fd), fraction(Gn, Gd)) :- is(mul(Fn, Gd), mul(Gn, Fd)).
isGreater(fraction(Fn, Fd), fraction(Gn, Gd)) :- isGreater(mul(Fn, Gd), mul(Gn, Fd)).
isLessEq(fraction(Fn, Fd), fraction(Gn, Gd)) :- isLessEq(mul(Fn, Gd), mul(Gn, Fd)).
isGreaterEq(fraction(Fn, Fd), fraction(Gn, Gd)) :- isGreaterEq(mul(Fn, Gd), mul(Gn, Fd)).

% list. Empty list is `nil`
% l(Elem, Next).

% Returns the last element of the list (the one that is followed by `nil`)
last(l(Elem, nil), Elem).
last(l(_, Elems), Elem) :- last(Elems, Elem).

% append a single element to list
append(Es, Elem, l(Elem, Es)).
";

The standard library of Prolog predicates.

The current Prolog syntax doesn’t accept “=”, “,”, and other goodies in queries, so this makes them possible:

• A = config(_, _). becomes A, eq(A, config(_, _)).