These functions return true if expr is of the specified type, and false otherwise.

An expression is of type logical if it is of type `and`, `or`, `xor`, `implies`, or `not`. For each of the types f, where f is one of `and`, `or`, `xor`, `implies`, or `not`, x is of type f if op(0, x) = f.

type/boolean

$\mathrm{type}\left(x<5\&comma;\mathrm{logical}\right)$

$\mathrm{false}$

$\mathrm{type}\left(a\mathbf{or}\mathbf{not}b\&comma;\mathrm{logical}\right)$

$\mathrm{true}$

$\mathrm{type}\left(1<2\mathbf{and}5<x\&comma;\mathrm{logical}\right)$

$\mathrm{false}$