Fundamentals of CS I (CS151 2001S) : Reference

eq? - determine if two values share the same memory

Parametersval1, a value
val2, another value
PurposeDetermines if val1 and val2 are equal in the sense that they share the same memory location. Typically only appropriate for symbolic and Boolean values.
ProducesA truth value: true (#t) if the two values are equal in the given sense, false (#f) if they're not.
PreconditionsExactly two parameters (verified).
> (eq? 2 2)
> (eq? 2 2 2)
eq?: expects 2 arguments, given 3: 2 2 2
> (eq? 2 (+ 1 1))
> (eq? "hello" "hello")
> (eq? 'hello 'hello)
> (eq? 'hello (car (list 'hello 'goodbye)))
> (eq? null null)
> (eq? (cons 'a null) (cons 'a null))
> (eq? 5.0 5)
> (eq? 5.0 5.0)

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