18. The search engine of claim 16 , wherein: a first of the commands comprises a bitcheck command embodying the specified set of characters; and a first of the co-processors is dedicated to execute the bitcheck command to generate a compliance signal indicating whether a selected input character is a member of the specified set of characters.
21. The search engine of claim 18 , wherein: a second of the commands comprises a count command embodying the specified range of instances; and a second of the co-processors is dedicated to execute the count command to generate a range signal indicating whether the number of input characters in the selected portion falls within the specified range of instances.