Exercise 1: A Right-Associative Exponentiation Level — Possible Solution
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THE NEW PRECEDENCE LEVEL
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    def factor(self):                 # unchanged, calls exponent() now instead of unary()
        expr = self.exponent()
        while self.match('STAR', 'SLASH'):
            ...

    def exponent(self):
        expr = self.unary()
        if self.match('CARET'):
            right = self.exponent()   # RECURSIVE call, not a while loop - makes it right-assoc
            expr = ('binary', 'CARET', expr, right)
        return expr

The key difference from every other binary level in the chapter's own
grammar: exponent() calls itself for the right-hand side (via an `if`,
not a `while`), instead of looping at its own level the way term() and
factor() do.

RESULTS
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    '2 ^ 3 ^ 2' parses as: (2.0 CARET (3.0 CARET 2.0))
    Evaluates to: 512.0
    Right-associative (2^(3^2)=2^9=512), not left ((2^3)^2=64): True

WHY THIS WORKS AS AN ANSWER
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Every other operator in the chapter's own grammar is left-associative,
built with a `while` loop that keeps nesting new operations on the
LEFT side of the growing tree. Exponentiation is the standard
counter-example in real-world grammars (mathematics itself defines it
right-associative), and the fix is structural, not a special case
bolted on: recursing into the SAME function for the right operand,
instead of looping, makes the tree grow rightward instead of leftward.
This confirms associativity is a genuine, deliberate choice encoded in
how a grammar rule is written, not an automatic consequence of a
binary operator existing at all.