ConfirmMatch

confirms that expr matches the pattern form, otherwise throwing a Failure to the nearest lexically surrounding Enclose.

ConfirmMatch[expr,form,info]

if expr does not match form, evaluates info and includes the result in the thrown Failure.

ConfirmMatch[expr,form,info,tag]

uses the tag tag for any thrown errors.

Details

Examples

Confirm that a expression matches a pattern, stopping evaluation if it does:

Create a function that throws an error when given an unexpected input:

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