Add support for reading and writing SPV files.

[pspp] / doc / expressions.texi

diff --git a/doc/expressions.texi b/doc/expressions.texi
index e468b8750ac457361b878a7788ac24e6d0e8a544..c530f7a7a839dddd3fe54434bb3e23d43bbff977 100644 (file)
--- a/doc/expressions.texi
+++ b/doc/expressions.texi
@@ -1,7 +1,16 @@
-@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/}
+@code{\NAME\}
 @end macro
 
 @node Expressions
@@ -264,7 +273,8 @@ The sections below describe each function in detail.
 * Set Membership::              ANY RANGE
 * Statistical Functions::       CFVAR MAX MEAN MEDIAN MIN SD SUM VARIANCE
 * String Functions::            CONCAT INDEX LENGTH LOWER LPAD LTRIM NUMBER 
-                                REPLACE RINDEX RPAD RTRIM STRING SUBSTR UPCASE
+                                REPLACE RINDEX RPAD RTRIM STRING STRUNC SUBSTR
+                                UPCASE
 * Time and Date::               CTIME.xxx DATE.xxx TIME.xxx XDATE.xxx
                                 DATEDIFF DATESUM
 * Miscellaneous Functions::     LAG YRMODA VALUELABEL
@@ -341,9 +351,14 @@ FUZZBITS}), which is 6 unless overridden.
 @end deftypefn
 
 @cindex truncation
-@deftypefn {Function} {} TRUNC (@var{number})
-Discards the fractional part of @var{number}; that is, rounds
-@var{number} towards zero.
+@deftypefn {Function} {} TRUNC (@var{number} [, @var{mult}[, @var{fuzzbits}]])
+Rounds @var{number} to a multiple of @var{mult}, toward zero.  For the
+default @var{mult} of 1, this is equivalent to discarding the
+fractional part of @var{number}.  Values that fall short of a multiple
+of @var{mult} by less than @var{fuzzbits} of errors in the
+least-significant bits of @var{number} are rounded away from zero.  If
+@var{fuzzbits} is not specified then the default is taken from SET
+FUZZBITS (@pxref{SET FUZZBITS}), which is 6 unless overridden.
 @end deftypefn
 
 @node Trigonometry
@@ -408,7 +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{})
@@ -424,10 +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})
@@ -691,6 +707,15 @@ format specifier @var{format}.  For example, @code{STRING(123.56, F5.1)}
 has the value @code{"123.6"}.
 @end deftypefn
 
+@cindex strings, trimming
+@cindex strings, truncating
+@cindex white space, trimming
+@deftypefn {Function} {} STRUNC (@var{string}, @var{n})
+Returns @var{string}, first trimming it to at most @var{n} bytes, then
+removing trailing spaces.  Returns an empty string if @var{n} is
+missing or negative.
+@end deftypefn
+
 @cindex substrings
 @cindex strings, taking substrings of
 @deftypefn {Function} {} SUBSTR (@var{string}, @var{start})