henri_3_18_21.py

from Question import Question
from Expression import Int, Plus, Equals, Var, Minus, Times, Negative

documentation = [
    "expr.to_pos_neg(): If expr looks like 'a - b', it is converted to 'a + -b'",
    "expr.pos_neg_to_minus(): If expr looks like 'a + -b', it is converted to 'a - b'",
    "expr.associate_l_to_r(): If expr looks like '(a + b) + c', it is converted to 'a + (b + c)'.  You can replace '+' with '*'.",
    "expr.associate_r_to_l(): Converts an expression that looks like 'a + (b + c)' to '(a + b) + c'.  You can replace '+' with '*'",
    "expr.rw_se(sub_expr, equal_expr): Rewrites every expression equal to subexpr inside of expr to equal_expr, but only if equal_expr means the same thing as sub_expr.",
    "expr.commute(): If expr looks like 'a + b', it is converted to 'b + a'.  You can replace '+' with '*'"
]

def check_answer(a0):
    return lambda a: a == a0

def conv_q(expr1_str, expr2_str, af):
    return Question("Convert the expression '{}' to '{}'".format(expr1_str, expr2_str), af)

questions = [
    #conv_q("1 + (2 + 3)", "1 + (3 + 2)", check_answer(Plus(Int(1), Plus(Int(3), Int(2))))),
    #conv_q("(2 * 3) * a", "(c * b) * a", check_answer(Times(Times(Var("c"), Var("b")), Var("a")))),
    conv_q("(1 * 2) + (2 * 3)", "(2 * 1) + (3 * 2)", check_answer(Plus(Times(Int(2), Int(1)), Times(Int(3), Int(2))))),
    conv_q("1 + ((2 + 3) + 4)", "1 + ((3 + 4) + 2)", check_answer(Plus(Int(1), Plus(Plus(Int(3), Int(4)), Int(2))))),
    conv_q("(1 - 3) - 2", "(1 - 2) - 3", check_answer(Minus(Minus(Int(1), Int(2)), Int(3)))),
    conv_q("1 + (2 + 3)", "3 + (2 + 1)", check_answer(Plus(Int(3), Plus(Int(2), Int(1))))),
    conv_q("(-3 - 2) - 1", "(-1 - 2) - 3", check_answer(Minus(Minus(Negative(Int(1)), Int(2)), Int(3)))),
    conv_q("1 + (2 + (3 + 4))", "4 + (3 + (2 + 1))", check_answer(Plus(Int(4), Plus(Int(3), Plus(Int(2), Int(1))))))
]