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10 lines
507 B
10 lines
507 B
2 years ago
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Exercise 5.39: Write a procedure
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lexical-address-lookup that implements the new lookup operation. It
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should take two arguments—a lexical address and a run-time environment—and
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return the value of the variable stored at the specified lexical address.
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Lexical-address-lookup should signal an error if the value of the
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variable is the symbol *unassigned*.331 Also write a procedure
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lexical-address-set! that implements the operation that changes the
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value of the variable at a specified lexical address.
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