Mention that a measure of 0 is occasionally seen.

diff --git a/doc/data-file-format.texi b/doc/data-file-format.texi
index 2186b6d411089552ca91d281d9f9388df43854a1..006395078d9cb56e9cc618c72fba9edd83f1cad9 100644 (file)
--- a/doc/data-file-format.texi
+++ b/doc/data-file-format.texi
@@ -582,6 +582,9 @@ Ordinal Scale
 Continuous Scale
 @end table
 
+Occasionally a value of 0 is seen here.  PSPP interprets this to mean
+a nominal scale.
+
 @item int32 width
 The width of the display column for the variable in characters.