#ifndef MATH_SORT_H
#define MATH_SORT_H 1
+/* Support for sorting cases.
+
+ Use sort_create_writer() to sort cases in the most general way:
+
+ - Create a casewriter with sort_create_writer(), specifying the sort
+ criteria.
+ - Write all of the cases to be sorted to the casewriter, e.g. with
+ casewriter_write().
+ - Obtain the sorted results with casewriter_make_reader().
+
+ sort_execute() and sort_execute_1var() are shortcuts for situations where the
+ cases are already available from a casereader.
+
+ All of these functions can efficiently sort data bigger than memory. */
+
struct subcase;
struct caseproto;
struct variable;