Catch

Catch[expr] returns the argument of the first Throw generated in the evaluation of expr.

Catch[expr, form] returns value from the first Throw[value, tag] for which form matches tag.

Catch[expr, form, f] returns f[value, tag].

Catch[expr, ... ] always returns the value of expr if no Throw was generated during the evaluation.

form can be any expression, and is often a pattern.

tag in Throw[value, tag] is re-evaluated every time it is compared to form.

See The Mathematica Book: Section 2.5.9.

See also: Check, CheckAbort.

Further Examples