maintains expr in an unevaluated form.
- Hold has attribute HoldAll and performs no operation on its arguments.
- Hold is removed by ReleaseHold. »
- Hold[e1,e2,…] maintains a sequence of unevaluated expressions to which a function can be applied using Apply.
- Even though expr itself is not evaluated, Hold[expr] may still evaluate if expr is of the form f[args], and upvalues for f have been defined. »
Introduced in 1988