6.2.1.6 Match Keys

A match-keys argument is a list of length equal to the number of primary keys. The match-keys restrict the actions of the table command to those records whose primary keys all satisfy the corresponding element of the match-keys list. The elements and their actions are:

#f

The false value matches any key in the corresponding position.

an object of type procedure

This procedure must take a single argument, the key in the corresponding position. Any key for which the procedure returns a non-false value is a match; Any key for which the procedure returns a #f is not.

other values

Any other value matches only those keys equal? to it.