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11 lines
611 B
11 lines
611 B
3 years ago
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Exercise 4.17: Draw diagrams of the environment
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in effect when evaluating the expression ⟨e3⟩ in the procedure in the
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text, comparing how this will be structured when definitions are interpreted
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sequentially with how it will be structured if definitions are scanned out as
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described. Why is there an extra frame in the transformed program? Explain
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why this difference in environment structure can never make a difference in the
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behavior of a correct program. Design a way to make the interpreter implement
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the “simultaneous” scope rule for internal definitions without constructing
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the extra frame.
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