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letrec
Learn letrec in Scheme with a construct-specific explanation, unique example, engineering boundary, and mastery check.
letrec is a focused Scheme topic inside Binding Forms. This lesson explains the construct itself, the state or value it operates on, and the observable result it produces.
Read the example as a small executable experiment. Identify the exact syntax that belongs to letrec, then change one input and predict the result before running it.
Topic-specific example
(letrec ((even? (lambda (n) (or (zero? n) (odd? (- n 1))))) (odd? (lambda (n) (and (not (zero? n)) (even? (- n 1)))))) (even? 10))
letrec has rules that are easy to miss when the example is copied mechanically. Check the feature-specific boundary shown by this construct: scope, mutability, evaluation order, type constraints, lifetime, error behavior, compile-time restrictions, or resource cleanup where applicable.