% Reference 9.1: reusable string normalization, splitting, joining, replacement, and conversions.
%% goal: answer(X0, X1)

answer(trim, X) :- trim("  Hello Eyepl  ", X).
answer(lower, X) :- lowercase("Hello Eyepl", X).
answer(upper, X) :- uppercase("Hello Eyepl", X).
answer(split, X) :- split("red,green,blue", ",", X).
answer(join, X) :- join([red, green, blue], ":", X).
answer(substring, X) :- substring("abcdef", 2, 3, X).
answer(replace, X) :- replace("red-green-red", "red", "blue", X).
answer(number_to_string, X) :- number_string(42, X).
answer(string_to_number, X) :- number_string(X, "3.5").
answer(atom_string, X) :- atom_string(eyepl, X).