The Common Lisp
loop macro has been extended with a clause for iterating over query results. This extension is available only when Common SQL has been loaded. For a full description of the rest of the Common Lisp
loop facility, including the possible return values, see Steele, Common Lisp: the Language , second edition.
Each iteration of the loop assigns the next record of the table to the variable var . The record is represented in Lisp as a list. Destructuring can be used in var to bind variables to specific attributes of the records resulting from query-expression . In conjunction with the panoply of existing clauses available from the
loop macro, the new iteration clause provides an integrated report generation facility.
loop example performs the following on each record returned as a result of a query: bind
name to the query result, find the salary (if any) from an associated hash-table, increment a count for salaries greater than 20000, accumulate the salary, and print the details. Finally, it prints the average salary.