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

An expression is of type boolean if it is of type type/relation, type type/logical or one of the Boolean constants true, false, or FAIL.

type/logical, type/relation, type/truefalse, type/truefalseFAIL

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

$\mathrm{true}$

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

$\mathrm{true}$

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

$\mathrm{true}$

$\mathrm{type}\left(\mathrm{false}\&comma;\mathrm{boolean}\right)$

$\mathrm{true}$