Update comment to reflect availability of random casereaders.

diff --git a/src/data/casefile.c b/src/data/casefile.c
index 9e31d431ce39410b0953515e79d1de5b12be0311..453fbf09da4a5af8f6a9effe85aeb3fe9d4fbad2 100644 (file)
--- a/src/data/casefile.c
+++ b/src/data/casefile.c
@@ -66,10 +66,10 @@
           during the reading phase.  Each casereader has an
           independent position in the casefile.
 
           during the reading phase.  Each casereader has an
           independent position in the casefile.
 

-          Casereaders may only move forward.  They cannot move
-          backward to arbitrary records or seek randomly.
-          Cloning casereaders is possible, but it is not yet
-          implemented.
+          Ordinary casereaders may only move forward.  They
+          cannot move backward to arbitrary records or seek
+          randomly.  Cloning casereaders is possible, but it is
+          not yet implemented.

 
           Use casefile_get_reader() to create a casereader for
           use in phase 2.  This also transitions from phase 1 to
 
           Use casefile_get_reader() to create a casereader for
           use in phase 2.  This also transitions from phase 1 to


@@ -80,6 +80,12 @@
           a case from a casereader.  Use casereader_destroy() to
           discard a casereader when it is no longer needed.
 
           a case from a casereader.  Use casereader_destroy() to
           discard a casereader when it is no longer needed.
 

+          "Random" casereaders, which support a seek operation,
+          may also be created.  These should not, generally, be
+          used for statistical procedures, because random access
+          is much slower than sequential access.  They are
+          intended for use by the GUI.
+

        3. Destruction.  This phase is optional.  The casefile is
           also read with casereaders in this phase, but the
           ability to create new casereaders is curtailed.
        3. Destruction.  This phase is optional.  The casefile is
           also read with casereaders in this phase, but the
           ability to create new casereaders is curtailed.