fbuf: New data structure for buffered file I/O.

[pspp] / doc / expressions.texi

diff --git a/doc/expressions.texi b/doc/expressions.texi
index 1141f3a53d723f0aba39d03b165447a961fd3d63..c530f7a7a839dddd3fe54434bb3e23d43bbff977 100644 (file)
--- a/doc/expressions.texi
+++ b/doc/expressions.texi
@@ -1,4 +1,13 @@
-@c Use @func when refering to a function.
+@c PSPP - a program for statistical analysis.
+@c Copyright (C) 2017 Free Software Foundation, Inc.
+@c Permission is granted to copy, distribute and/or modify this document
+@c under the terms of the GNU Free Documentation License, Version 1.3
+@c or any later version published by the Free Software Foundation;
+@c with no Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts.
+@c A copy of the license is included in the section entitled "GNU
+@c Free Documentation License".
+@c
+@c Use @func when referring to a function.
 @c Use @deftypefn for their definitions 
 @macro func{NAME}
 @code{\NAME\}
@@ -414,7 +423,11 @@ functions.  In particular, user-missing values for numeric variables
 are converted to system-missing values.
 
 @deftypefn {Function} {} MISSING (@var{expr})
-Returns 1 if @var{expr} has the system-missing value, 0 otherwise.
+When @var{expr} is simply the name of a numeric variable, returns 1 if
+the variable has the system-missing value or if it is user-missing.
+For any other value 0 is returned.
+If @var{expr} takes another form, the function returns 1 if the value is
+system-missing, 0 otherwise.
 @end deftypefn
 
 @deftypefn {Function} {} NMISS (@var{expr} [, @var{expr}]@dots{})
@@ -430,10 +443,7 @@ variable ranges using the @code{@var{var1} TO @var{var2}} syntax.
 @end deftypefn
 
 @deftypefn {Function} {} SYSMIS (@var{expr})
-When @var{expr} is simply the name of a numeric variable, returns 1 if
-the variable has the system-missing value, 0 if it is user-missing or
-not missing.  If given @var{expr} takes another form, results in 1 if
-the value is system-missing, 0 otherwise.
+Returns 1 if @var{expr} has the system-missing value, 0 otherwise.
 @end deftypefn
 
 @deftypefn {Function} {} VALUE (@var{variable})