Fix missing @clicksequence problem with older Texinfo versions.

[pspp-builds.git] / doc / expressions.texi

diff --git a/doc/expressions.texi b/doc/expressions.texi
index 87355293e79e2e1c2e155ac8339bb1a56b2626c7..345e59669d36ad6f0cc08a8f95251e3b0760fdbc 100644 (file)
--- a/doc/expressions.texi
+++ b/doc/expressions.texi
@@ -1,33 +1,31 @@
-@node Expressions, Data Input and Output, Language, Top
+@node Expressions

 @chapter Mathematical Expressions
 @cindex expressions, mathematical
 @cindex mathematical expressions
 
 @chapter Mathematical Expressions
 @cindex expressions, mathematical
 @cindex mathematical expressions
 

-Some PSPP commands use expressions, which share a common syntax
-among all PSPP commands.  Expressions are made up of
-@dfn{operands}, which can be numbers, strings, or variable names,
-separated by @dfn{operators}.  There are five types of operators:
-grouping, arithmetic, logical, relational, and functions.
-
-Every operator takes one or more @dfn{arguments} as input and produces
-or @dfn{returns} exactly one result as output.  Both strings and numeric
-values can be used as arguments and are produced as results, but each
-operator accepts only specific combinations of numeric and string values
-as arguments.  With few exceptions, operator arguments may be
+Expressions share a common syntax each place they appear in PSPP
+commands.  Expressions are made up of @dfn{operands}, which can be
+numbers, strings, or variable names, separated by @dfn{operators}.
+There are five types of operators: grouping, arithmetic, logical,
+relational, and functions.
+
+Every operator takes one or more operands as input and yields exactly
+one result as output.  Depending on the operator, operands accept
+strings or numbers as operands.  With few exceptions, operands may be

 full-fledged expressions in themselves.
 
 @menu
 full-fledged expressions in themselves.
 
 @menu

-* Boolean Values::              Boolean values.
-* Missing Values in Expressions::  Using missing values in expressions.
-* Grouping Operators::          parentheses
-* Arithmetic Operators::        add sub mul div pow
-* Logical Operators::           AND NOT OR
-* Relational Operators::        EQ GE GT LE LT NE
-* Functions::                   More-sophisticated operators.
-* Order of Operations::         Operator precedence.
+* Boolean Values::                 Boolean values
+* Missing Values in Expressions::  Using missing values in expressions
+* Grouping Operators::             parentheses
+* Arithmetic Operators::           add sub mul div pow
+* Logical Operators::              AND NOT OR
+* Relational Operators::           EQ GE GT LE LT NE
+* Functions::                      More-sophisticated operators
+* Order of Operations::            Operator precedence

 @end menu
 
 @end menu
 

-@node Boolean Values, Missing Values in Expressions, Expressions, Expressions
+@node Boolean Values

 @section Boolean Values
 @cindex Boolean
 @cindex values, Boolean
 @section Boolean Values
 @cindex Boolean
 @cindex values, Boolean


@@ -39,29 +37,31 @@ System-missing is neither true nor false and indicates that the true
 value is unknown.
 
 Boolean-typed operands or function arguments must take on one of these
 value is unknown.
 
 Boolean-typed operands or function arguments must take on one of these

-three values.  Other values are considered false, but cause an error
+three values.  Other values are considered false, but provoke a warning

 when the expression is evaluated.
 
 Strings and Booleans are not compatible, and neither may be used in
 place of the other.
 
 when the expression is evaluated.
 
 Strings and Booleans are not compatible, and neither may be used in
 place of the other.
 

-@node Missing Values in Expressions, Grouping Operators, Boolean Values, Expressions
+@node Missing Values in Expressions

 @section Missing Values in Expressions
 
 @section Missing Values in Expressions
 

-String missing values are not treated specially in expressions.  Most
-numeric operators return system-missing when given system-missing
-arguments.  Exceptions are listed under particular operator
-descriptions.
+Most numeric operators yield system-missing when given any
+system-missing operand.  A string operator given any system-missing
+operand typically results in the empty string.  Exceptions are listed
+under particular operator descriptions.
+
+String user-missing values are not treated specially in expressions.

 
 User-missing values for numeric variables are always transformed into
 
 User-missing values for numeric variables are always transformed into

-the system-missing value, except inside the arguments  to the
+the system-missing value, except inside the arguments to the

 @code{VALUE} and @code{SYSMIS} functions.
 
 The missing-value functions can be used to precisely control how missing
 values are treated in expressions.  @xref{Missing Value Functions}, for
 more details.
 
 @code{VALUE} and @code{SYSMIS} functions.
 
 The missing-value functions can be used to precisely control how missing
 values are treated in expressions.  @xref{Missing Value Functions}, for
 more details.
 

-@node Grouping Operators, Arithmetic Operators, Missing Values in Expressions, Expressions
+@node Grouping Operators

 @section Grouping Operators
 @cindex parentheses
 @cindex @samp{(  )}
 @section Grouping Operators
 @cindex parentheses
 @cindex @samp{(  )}


@@ -74,40 +74,43 @@ expression with parentheses to force early evaluation.
 Parentheses also surround the arguments to functions, but in that
 situation they act as punctuators, not as operators.
 
 Parentheses also surround the arguments to functions, but in that
 situation they act as punctuators, not as operators.
 

-@node Arithmetic Operators, Logical Operators, Grouping Operators, Expressions
+@node Arithmetic Operators

 @section Arithmetic Operators
 @cindex operators, arithmetic
 @cindex arithmetic operators
 
 @section Arithmetic Operators
 @cindex operators, arithmetic
 @cindex arithmetic operators
 

-The arithmetic operators take numeric arguments and produce numeric
+The arithmetic operators take numeric operands and produce numeric

 results.
 
 @table @code
 @cindex @samp{+}
 @cindex addition
 @item @var{a} + @var{b}
 results.
 
 @table @code
 @cindex @samp{+}
 @cindex addition
 @item @var{a} + @var{b}

-Adds @var{a} and @var{b}, returning the sum.
+Yields the sum of @var{a} and @var{b}.

 
 @cindex @samp{-}
 @cindex subtraction
 @item @var{a} - @var{b}
 
 @cindex @samp{-}
 @cindex subtraction
 @item @var{a} - @var{b}

-Subtracts @var{b} from @var{a}, returning the difference.
+Subtracts @var{b} from @var{a} and yields the difference.

 
 @cindex @samp{*}
 @cindex multiplication
 @item @var{a} * @var{b}
 
 @cindex @samp{*}
 @cindex multiplication
 @item @var{a} * @var{b}

-Multiplies @var{a} and @var{b}, returning the product.
+Yields the product of @var{a} and @var{b}.  If either @var{a} or
+@var{b} is 0, then the result is 0, even if the other operand is
+missing.

 
 @cindex @samp{/}
 @cindex division
 @item @var{a} / @var{b}
 
 @cindex @samp{/}
 @cindex division
 @item @var{a} / @var{b}

-Divides @var{a} by @var{b}, returning the quotient.  If @var{b} is
-zero, the result is system-missing.
+Divides @var{a} by @var{b} and yields the quotient.  If @var{a} is 0,
+then the result is 0, even if @var{b} is missing.  If @var{b} is zero,
+the result is system-missing.

 
 @cindex @samp{**}
 @cindex exponentiation
 @item @var{a} ** @var{b}
 
 @cindex @samp{**}
 @cindex exponentiation
 @item @var{a} ** @var{b}

-Returns the result of raising @var{a} to the power @var{b}.  If
+Yields the result of raising @var{a} to the power @var{b}.  If

 @var{a} is negative and @var{b} is not an integer, the result is
 system-missing.  The result of @code{0**0} is system-missing as well.
 
 @var{a} is negative and @var{b} is not an integer, the result is
 system-missing.  The result of @code{0**0} is system-missing as well.
 


@@ -117,7 +120,7 @@ system-missing.  The result of @code{0**0} is system-missing as well.
 Reverses the sign of @var{a}.  
 @end table
 
 Reverses the sign of @var{a}.  
 @end table
 

-@node Logical Operators, Relational Operators, Arithmetic Operators, Expressions
+@node Logical Operators

 @section Logical Operators
 @cindex logical operators
 @cindex operators, logical
 @section Logical Operators
 @cindex logical operators
 @cindex operators, logical


@@ -127,10 +130,10 @@ Reverses the sign of @var{a}.
 @cindex Boolean
 @cindex values, system-missing
 @cindex system-missing
 @cindex Boolean
 @cindex values, system-missing
 @cindex system-missing

-The logical operators take logical arguments and produce logical
-results, meaning ``true or false''.  PSPP logical operators are
+The logical operators take logical operands and produce logical
+results, meaning ``true or false.''  Logical operators are

 not true Boolean operators because they may also result in a
 not true Boolean operators because they may also result in a

-system-missing value.
+system-missing value.  @xref{Boolean Values}, for more information.

 
 @table @code
 @cindex @code{AND}
 
 @table @code
 @cindex @code{AND}


@@ -140,8 +143,8 @@ system-missing value.
 @item @var{a} AND @var{b}
 @itemx @var{a} & @var{b}
 True if both @var{a} and @var{b} are true, false otherwise.  If one
 @item @var{a} AND @var{b}
 @itemx @var{a} & @var{b}
 True if both @var{a} and @var{b} are true, false otherwise.  If one

-argument is false, the result is false even if the other is missing.  If
-both arguments are missing, the result is missing.
+operand is false, the result is false even if the other is missing.  If
+both operands are missing, the result is missing.

 
 @cindex @code{OR}
 @cindex @samp{|}
 
 @cindex @code{OR}
 @cindex @samp{|}


@@ -149,9 +152,9 @@ both arguments are missing, the result is missing.
 @cindex logical union
 @item @var{a} OR @var{b}
 @itemx @var{a} | @var{b}
 @cindex logical union
 @item @var{a} OR @var{b}
 @itemx @var{a} | @var{b}

-True if at least one of @var{a} and @var{b} is true.  If one argument is
-true, the result is true even if the other argument is missing.  If both
-arguments are missing, the result is missing.
+True if at least one of @var{a} and @var{b} is true.  If one operand is
+true, the result is true even if the other operand is missing.  If both
+operands are missing, the result is missing.

 
 @cindex @code{NOT}
 @cindex @samp{~}
 
 @cindex @code{NOT}
 @cindex @samp{~}


@@ -159,14 +162,14 @@ arguments are missing, the result is missing.
 @cindex logical inversion
 @item NOT @var{a}
 @itemx ~ @var{a}
 @cindex logical inversion
 @item NOT @var{a}
 @itemx ~ @var{a}

-True if @var{a} is false.  If the argument is missing, then the result
+True if @var{a} is false.  If the operand is missing, then the result

 is missing.
 @end table
 
 is missing.
 @end table
 

-@node Relational Operators, Functions, Logical Operators, Expressions
+@node Relational Operators

 @section Relational Operators
 
 @section Relational Operators
 

-The relational operators take numeric or string arguments and produce Boolean
+The relational operators take numeric or string operands and produce Boolean

 results.
 
 Strings cannot be compared to numbers.  When strings of different
 results.
 
 Strings cannot be compared to numbers.  When strings of different


@@ -174,8 +177,8 @@ lengths are compared, the shorter string is right-padded with spaces
 to match the length of the longer string.
 
 The results of string comparisons, other than tests for equality or
 to match the length of the longer string.
 
 The results of string comparisons, other than tests for equality or

-inequality, are dependent on the character set in use.  String
-comparisons are case-sensitive.
+inequality, depend on the character set in use.  String comparisons
+are case-sensitive.

 
 @table @code
 @cindex equality, testing
 
 @table @code
 @cindex equality, testing


@@ -222,10 +225,10 @@ True if @var{a} is greater than @var{b}.
 @item @var{a} NE @var{b}
 @itemx @var{a} ~= @var{b}
 @itemx @var{a} <> @var{b}
 @item @var{a} NE @var{b}
 @itemx @var{a} ~= @var{b}
 @itemx @var{a} <> @var{b}

-True is @var{a} is not equal to @var{b}.
+True if @var{a} is not equal to @var{b}.

 @end table
 
 @end table
 

-@node Functions, Order of Operations, Relational Operators, Expressions
+@node Functions

 @section Functions
 @cindex functions
 
 @section Functions
 @cindex functions
 


@@ -238,31 +241,32 @@ True is @var{a} is not equal to @var{b}.
 PSPP functions provide mathematical abilities above and beyond
 those possible using simple operators.  Functions have a common
 syntax: each is composed of a function name followed by a left
 PSPP functions provide mathematical abilities above and beyond
 those possible using simple operators.  Functions have a common
 syntax: each is composed of a function name followed by a left

-parenthesis, one or more arguments, and a right parenthesis.  Function
-names are @strong{not} reserved; their names are specially treated
-only when followed by a left parenthesis: @code{EXP(10)} refers to the
-constant value @code{e} raised to the 10th power, but @code{EXP} by
-itself refers to the value of variable EXP.
+parenthesis, one or more arguments, and a right parenthesis.
+
+Function names are not reserved.  Their names are specially treated
+only when followed by a left parenthesis, so that @code{EXP(10)}
+refers to the constant value @code{e} raised to the 10th power, but
+@code{EXP} by itself refers to the value of variable EXP.

 
 The sections below describe each function in detail.
 
 @menu
 
 The sections below describe each function in detail.
 
 @menu

-* Advanced Mathematics::        EXP LG10 LN SQRT
+* Mathematics::                 EXP LG10 LN LNGAMMA SQRT

 * Miscellaneous Mathematics::   ABS MOD MOD10 RND TRUNC
 * Trigonometry::                ACOS ARCOS ARSIN ARTAN ASIN ATAN COS SIN TAN
 * Missing Value Functions::     MISSING NMISS NVALID SYSMIS VALUE
 * Miscellaneous Mathematics::   ABS MOD MOD10 RND TRUNC
 * Trigonometry::                ACOS ARCOS ARSIN ARTAN ASIN ATAN COS SIN TAN
 * Missing Value Functions::     MISSING NMISS NVALID SYSMIS VALUE

-* Pseudo-Random Numbers::       NORMAL UNIFORM

 * Set Membership::              ANY RANGE
 * Statistical Functions::       CFVAR MAX MEAN MIN SD SUM VARIANCE
 * String Functions::            CONCAT INDEX LENGTH LOWER LPAD LTRIM NUMBER 
                                 RINDEX RPAD RTRIM STRING SUBSTR UPCASE
 * Set Membership::              ANY RANGE
 * Statistical Functions::       CFVAR MAX MEAN MIN SD SUM VARIANCE
 * String Functions::            CONCAT INDEX LENGTH LOWER LPAD LTRIM NUMBER 
                                 RINDEX RPAD RTRIM STRING SUBSTR UPCASE

-* Time & Date::                 CTIME.xxx DATE.xxx TIME.xxx XDATE.xxx
-* Miscellaneous Functions::     LAG YRMODA
-* Functions Not Implemented::   CDF.xxx CDFNORM IDF.xxx NCDF.xxx PROBIT RV.xxx
+* Time and Date::               CTIME.xxx DATE.xxx TIME.xxx XDATE.xxx
+                                DATEDIFF DATESUM
+* Miscellaneous Functions::     LAG YRMODA VALUELABEL
+* Statistical Distribution Functions::  PDF CDF SIG IDF RV NPDF NCDF

 @end menu
 
 @end menu
 

-@node Advanced Mathematics, Miscellaneous Mathematics, Functions, Functions
-@subsection Advanced Mathematical Functions
+@node Mathematics
+@subsection Mathematical Functions

 @cindex mathematics, advanced
 
 Advanced mathematical functions take numeric arguments and produce
 @cindex mathematics, advanced
 
 Advanced mathematical functions take numeric arguments and produce


@@ -283,13 +287,18 @@ Takes the base-@i{e} logarithm of @var{number}.  If @var{number} is
 not positive, the result is system-missing.
 @end deftypefn
 
 not positive, the result is system-missing.
 @end deftypefn
 

+@deftypefn {Function} {} LNGAMMA (@var{number})
+Yields the base-@i{e} logarithm of the complete gamma of @var{number}.
+If @var{number} is a negative integer, the result is system-missing.
+@end deftypefn
+

 @cindex square roots
 @deftypefn {Function} {} SQRT (@var{number})
 Takes the square root of @var{number}.  If @var{number} is negative,
 the result is system-missing.
 @end deftypefn
 
 @cindex square roots
 @deftypefn {Function} {} SQRT (@var{number})
 Takes the square root of @var{number}.  If @var{number} is negative,
 the result is system-missing.
 @end deftypefn
 

-@node Miscellaneous Mathematics, Trigonometry, Advanced Mathematics, Functions
+@node Miscellaneous Mathematics

 @subsection Miscellaneous Mathematical Functions
 @cindex mathematics, miscellaneous
 
 @subsection Miscellaneous Mathematical Functions
 @cindex mathematics, miscellaneous
 


@@ -304,9 +313,9 @@ Results in the absolute value of @var{number}.
 @cindex modulus
 @deftypefn {Function} {} MOD (@var{numerator}, @var{denominator})
 Returns the remainder (modulus) of @var{numerator} divided by
 @cindex modulus
 @deftypefn {Function} {} MOD (@var{numerator}, @var{denominator})
 Returns the remainder (modulus) of @var{numerator} divided by

-@var{denominator}.  If @var{denominator} is 0, the result is
-system-missing.  However, if @var{numerator} is 0 and
-@var{denominator} is system-missing, the result is 0.
+@var{denominator}.  If @var{numerator} is 0, then the result is 0,
+even if @var{denominator} is missing.  If @var{denominator} is 0, the
+result is system-missing.

 @end deftypefn
 
 @cindex modulus, by 10
 @end deftypefn
 
 @cindex modulus, by 10


@@ -327,7 +336,7 @@ Discards the fractional part of @var{number}; that is, rounds
 @var{number} towards zero.
 @end deftypefn
 
 @var{number} towards zero.
 @end deftypefn
 

-@node Trigonometry, Missing Value Functions, Miscellaneous Mathematics, Functions
+@node Trigonometry

 @subsection Trigonometric Functions
 @cindex trigonometry
 
 @subsection Trigonometric Functions
 @cindex trigonometry
 


@@ -337,13 +346,16 @@ results.
 @cindex arccosine
 @cindex inverse cosine
 @deftypefn {Function} {} ARCOS (@var{number})
 @cindex arccosine
 @cindex inverse cosine
 @deftypefn {Function} {} ARCOS (@var{number})

+@deftypefnx {Function} {} ACOS (@var{number})

 Takes the arccosine, in radians, of @var{number}.  Results in
 Takes the arccosine, in radians, of @var{number}.  Results in

-system-missing if @var{number} is not between -1 and 1.
+system-missing if @var{number} is not between -1 and 1 inclusive.
+This function is a PSPP extension.

 @end deftypefn
 
 @cindex arcsine
 @cindex inverse sine
 @deftypefn {Function} {} ARSIN (@var{number})
 @end deftypefn
 
 @cindex arcsine
 @cindex inverse sine
 @deftypefn {Function} {} ARSIN (@var{number})

+@deftypefnx {Function} {} ASIN (@var{number})

 Takes the arcsine, in radians, of @var{number}.  Results in
 system-missing if @var{number} is not between -1 and 1 inclusive.
 @end deftypefn
 Takes the arcsine, in radians, of @var{number}.  Results in
 system-missing if @var{number} is not between -1 and 1 inclusive.
 @end deftypefn


@@ -351,6 +363,7 @@ system-missing if @var{number} is not between -1 and 1 inclusive.
 @cindex arctangent
 @cindex inverse tangent
 @deftypefn {Function} {} ARTAN (@var{number})
 @cindex arctangent
 @cindex inverse tangent
 @deftypefn {Function} {} ARTAN (@var{number})

+@deftypefnx {Function} {} ATAN (@var{number})

 Takes the arctangent, in radians, of @var{number}.
 @end deftypefn
 
 Takes the arctangent, in radians, of @var{number}.
 @end deftypefn
 


@@ -372,17 +385,17 @@ of @var{angle} that are too close to odd multiples of pi/2.
 Portability: none.
 @end deftypefn
 
 Portability: none.
 @end deftypefn
 

-@node Missing Value Functions, Pseudo-Random Numbers, Trigonometry, Functions
+@node Missing Value Functions

 @subsection Missing-Value Functions
 @cindex missing values
 @cindex values, missing
 @cindex functions, missing-value
 
 Missing-value functions take various numeric arguments and yield
 @subsection Missing-Value Functions
 @cindex missing values
 @cindex values, missing
 @cindex functions, missing-value
 
 Missing-value functions take various numeric arguments and yield

-various types of results.  Note that the normal rules of evaluation
-apply within expression arguments to these functions.  In particular,
-user-missing values for numeric variables are converted to
-system-missing values.
+various types of results.  Except where otherwise stated below, the
+normal rules of evaluation apply within expression arguments to these
+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.
 
 @deftypefn {Function} {} MISSING (@var{expr})
 Returns 1 if @var{expr} has the system-missing value, 0 otherwise.


@@ -390,16 +403,14 @@ Returns 1 if @var{expr} has the system-missing value, 0 otherwise.
 
 @deftypefn {Function} {} NMISS (@var{expr} [, @var{expr}]@dots{})
 Each argument must be a numeric expression.  Returns the number of
 
 @deftypefn {Function} {} NMISS (@var{expr} [, @var{expr}]@dots{})
 Each argument must be a numeric expression.  Returns the number of

-system-missing values in the list.  As a special extension,
-the syntax @code{@var{var1} TO @var{var2}} may be used to refer to a
-range of variables; see @ref{Sets of Variables}, for more details.
+system-missing values in the list, which may include variable ranges
+using the @code{@var{var1} TO @var{var2}} syntax.

 @end deftypefn
 
 @deftypefn {Function} {} NVALID (@var{expr} [, @var{expr}]@dots{})
 Each argument must be a numeric expression.  Returns the number of
 @end deftypefn
 
 @deftypefn {Function} {} NVALID (@var{expr} [, @var{expr}]@dots{})
 Each argument must be a numeric expression.  Returns the number of

-values in the list that are not system-missing.  As a special extension,
-the syntax @code{@var{var1} TO @var{var2}} may be used to refer to a
-range of variables; see @ref{Sets of Variables}, for more details.
+values in the list that are not system-missing.  The list may include
+variable ranges using the @code{@var{var1} TO @var{var2}} syntax.

 @end deftypefn
 
 @deftypefn {Function} {} SYSMIS (@var{expr})
 @end deftypefn
 
 @deftypefn {Function} {} SYSMIS (@var{expr})


@@ -412,55 +423,11 @@ the value is system-missing, 0 otherwise.
 @deftypefn {Function} {} VALUE (@var{variable})
 Prevents the user-missing values of @var{variable} from being
 transformed into system-missing values, and always results in the
 @deftypefn {Function} {} VALUE (@var{variable})
 Prevents the user-missing values of @var{variable} from being
 transformed into system-missing values, and always results in the

-actual value of @var{variable}, whether it is user-missing,
-system-missing or not missing at all.
-@end deftypefn
-
-@node Pseudo-Random Numbers, Set Membership, Missing Value Functions, Functions
-@subsection Pseudo-Random Number Generation Functions
-@cindex random numbers
-@cindex pseudo-random numbers (see random numbers)
-
-Pseudo-random number generation functions take numeric arguments and
-produce numeric results.
-
-PSPP uses the alleged RC4 cipher as a pseudo-random number generator
-(PRNG).  The bytes output by this PRNG are system-independent for a
-given random seed, but differences in endianness and floating-point
-formats will make PRNG results differ from system to system.  RC4
-should produce high-quality random numbers for simulation purposes.
-(If you're concerned about the quality of the random number generator,
-well, you're using a statistical processing package---analyze it!)
-
-PSPP's implementation of RC4 has not undergone any security auditing.
-Furthermore, various precautions that would be necessary for secure
-operation, such as secure seeding and discarding the first several
-bytes of output, have not been taken.  Therefore, PSPP's
-implementation of RC4 should not be used for security purposes.
-
-@cindex random numbers, normally-distributed
-@deftypefn {Function} {} NORMAL (@var{number})
-Results in a random number.  Results from @code{NORMAL} are normally
-distributed with a mean of 0 and a standard deviation of @var{number}.
-@end deftypefn
-
-@cindex random numbers, uniformly-distributed
-@deftypefn {Function} {} UNIFORM (@var{number})
-Results in a random number between 0 and @var{number}.  Results from
-@code{UNIFORM} are evenly distributed across its entire range.  There
-may be a maximum on the largest random number ever generated---this is
-often 
-@ifinfo 
-2**31-1 
-@end ifinfo
-@tex
-$2^{31}-1$
-@end tex
-(2,147,483,647), but it may be orders of magnitude
-higher or lower.
-@end deftypefn
-
-@node Set Membership, Statistical Functions, Pseudo-Random Numbers, Functions
+actual value of @var{variable}, whether it is valid, user-missing, or
+system-missing.
+@end deftypefn
+
+@node Set Membership

 @subsection Set-Membership Functions
 @cindex set membership
 @cindex membership, of set
 @subsection Set-Membership Functions
 @cindex set membership
 @cindex membership, of set


@@ -489,7 +456,7 @@ System-missing values in @var{set} do not cause RANGE to return
 system-missing.
 @end deftypefn
 
 system-missing.
 @end deftypefn
 

-@node Statistical Functions, String Functions, Set Membership, Functions
+@node Statistical Functions

 @subsection Statistical Functions
 @cindex functions, statistical
 @cindex statistics
 @subsection Statistical Functions
 @cindex functions, statistical
 @cindex statistics


@@ -500,66 +467,62 @@ other can only be computed on numeric values.  Their results have the
 same type as their arguments.  The current case's weighting factor
 (@pxref{WEIGHT}) has no effect on statistical functions.
 
 same type as their arguments.  The current case's weighting factor
 (@pxref{WEIGHT}) has no effect on statistical functions.
 

+These functions' argument lists may include entire ranges of variables
+using the @code{@var{var1} TO @var{var2}} syntax.
+

 @cindex arguments, minimum valid
 @cindex minimum valid number of arguments
 @cindex arguments, minimum valid
 @cindex minimum valid number of arguments

-With statistical functions it is possible to specify a minimum number of
-non-missing arguments for the function to be evaluated.  To do so,
-append a dot and the number to the function name.  For instance, to
-specify a minimum of three valid arguments to the MEAN function, use the
-name @code{MEAN.3}.
+Unlike most functions, statistical functions can return non-missing
+values even when some of their arguments are missing.  Most
+statistical functions, by default, require only 1 non-missing value to
+have a non-missing return, but CFVAR, SD, and VARIANCE require 2.
+These defaults can be increased (but not decreased) by appending a dot
+and the minimum number of valid arguments to the function name.  For
+example, @code{MEAN.3(X, Y, Z)} would only return non-missing if all
+of @samp{X}, @samp{Y}, and @samp{Z} were valid.

 
 @cindex coefficient of variation
 @cindex variation, coefficient of
 @deftypefn {Function} {} CFVAR (@var{number}, @var{number}[, @dots{}])
 Results in the coefficient of variation of the values of @var{number}.
 
 @cindex coefficient of variation
 @cindex variation, coefficient of
 @deftypefn {Function} {} CFVAR (@var{number}, @var{number}[, @dots{}])
 Results in the coefficient of variation of the values of @var{number}.

-This function requires at least two valid arguments to give a
-non-missing result.  (The coefficient of variation is the standard
-deviation divided by the mean.)
+(The coefficient of variation is the standard deviation divided by the
+mean.)

 @end deftypefn
 
 @cindex maximum
 @deftypefn {Function} {} MAX (@var{value}, @var{value}[, @dots{}])
 Results in the value of the greatest @var{value}.  The @var{value}s may
 @end deftypefn
 
 @cindex maximum
 @deftypefn {Function} {} MAX (@var{value}, @var{value}[, @dots{}])
 Results in the value of the greatest @var{value}.  The @var{value}s may

-be numeric or string.  Although at least two arguments must be given,
-only one need be valid for MAX to give a non-missing result.
+be numeric or string.

 @end deftypefn
 
 @cindex mean
 @deftypefn {Function} {} MEAN (@var{number}, @var{number}[, @dots{}])
 @end deftypefn
 
 @cindex mean
 @deftypefn {Function} {} MEAN (@var{number}, @var{number}[, @dots{}])

-Results in the mean of the values of @var{number}.  Although at least
-two arguments must be given, only one need be valid for MEAN to give a
-non-missing result.
+Results in the mean of the values of @var{number}.

 @end deftypefn
 
 @cindex minimum
 @deftypefn {Function} {} MIN (@var{number}, @var{number}[, @dots{}])
 Results in the value of the least @var{value}.  The @var{value}s may
 @end deftypefn
 
 @cindex minimum
 @deftypefn {Function} {} MIN (@var{number}, @var{number}[, @dots{}])
 Results in the value of the least @var{value}.  The @var{value}s may

-be numeric or string.  Although at least two arguments must be given,
-only one need be valid for MAX to give a non-missing result.
+be numeric or string.

 @end deftypefn
 
 @cindex standard deviation
 @cindex deviation, standard
 @deftypefn {Function} {} SD (@var{number}, @var{number}[, @dots{}])
 Results in the standard deviation of the values of @var{number}.
 @end deftypefn
 
 @cindex standard deviation
 @cindex deviation, standard
 @deftypefn {Function} {} SD (@var{number}, @var{number}[, @dots{}])
 Results in the standard deviation of the values of @var{number}.

-This function requires at least two valid arguments to give a
-non-missing result.

 @end deftypefn
 
 @cindex sum
 @deftypefn {Function} {} SUM (@var{number}, @var{number}[, @dots{}])
 @end deftypefn
 
 @cindex sum
 @deftypefn {Function} {} SUM (@var{number}, @var{number}[, @dots{}])

-Results in the sum of the values of @var{number}.  Although at least two
-arguments must be given, only one need by valid for SUM to give a
-non-missing result.
+Results in the sum of the values of @var{number}.

 @end deftypefn
 
 @cindex variance
 @deftypefn {Function} {} VARIANCE (@var{number}, @var{number}[, @dots{}])
 @end deftypefn
 
 @cindex variance
 @deftypefn {Function} {} VARIANCE (@var{number}, @var{number}[, @dots{}])

-Results in the variance of the values of @var{number}.  This function
-requires at least two valid arguments to give a non-missing result.
+Results in the variance of the values of @var{number}.

 @end deftypefn
 
 @end deftypefn
 

-@node String Functions, Time & Date, Statistical Functions, Functions
+@node String Functions

 @subsection String Functions
 @cindex functions, string
 @cindex string functions
 @subsection String Functions
 @cindex functions, string
 @cindex string functions


@@ -577,18 +540,19 @@ The resultant string is truncated to a maximum of 255 characters.
 @cindex searching strings
 @deftypefn {Function} {} INDEX (@var{haystack}, @var{needle})
 Returns a positive integer indicating the position of the first
 @cindex searching strings
 @deftypefn {Function} {} INDEX (@var{haystack}, @var{needle})
 Returns a positive integer indicating the position of the first

-occurrence @var{needle} in @var{haystack}.  Returns 0 if @var{haystack}
+occurrence of @var{needle} in @var{haystack}.  Returns 0 if @var{haystack}

 does not contain @var{needle}.  Returns system-missing if @var{needle}
 is an empty string.
 @end deftypefn
 
 does not contain @var{needle}.  Returns system-missing if @var{needle}
 is an empty string.
 @end deftypefn
 

-@deftypefn {Function} {} INDEX (@var{haystack}, @var{needle}, @var{divisor})
-Divides @var{needle} into parts, each with length @var{divisor}.
-Searches @var{haystack} for the first occurrence of each part, and
+@deftypefn {Function} {} INDEX (@var{haystack}, @var{needles}, @var{needle_len})
+Divides @var{needles} into one or more needles, each with length
+@var{needle_len}.
+Searches @var{haystack} for the first occurrence of each needle, and

 returns the smallest value.  Returns 0 if @var{haystack} does not
 returns the smallest value.  Returns 0 if @var{haystack} does not

-contain any part in @var{needle}.  It is an error if @var{divisor}
-cannot be evenly divided into the length of @var{needle}.  Returns
-system-missing if @var{needle} is an empty string.
+contain any part in @var{needle}.  It is an error if @var{needle_len}
+does not evenly divide the length of @var{needles}.  Returns
+system-missing if @var{needles} is an empty string.

 @end deftypefn
 
 @cindex strings, finding length of
 @end deftypefn
 
 @cindex strings, finding length of


@@ -620,9 +584,9 @@ if @var{padding} does not contain exactly one character.
 @end deftypefn
 
 @cindex strings, trimming
 @end deftypefn
 
 @cindex strings, trimming

-@cindex whitespace, trimming
+@cindex white space, trimming

 @deftypefn {Function} {} LTRIM (@var{string})
 @deftypefn {Function} {} LTRIM (@var{string})

-Returns @var{string}, after removing leading spaces.  Other whitespace,
+Returns @var{string}, after removing leading spaces.  Other white space,

 such as tabs, carriage returns, line feeds, and vertical tabs, is not
 removed.
 @end deftypefn
 such as tabs, carriage returns, line feeds, and vertical tabs, is not
 removed.
 @end deftypefn


@@ -654,12 +618,12 @@ occurrence of @var{needle} in @var{haystack}.  Returns 0 if
 @var{needle} is an empty string.
 @end deftypefn
 
 @var{needle} is an empty string.
 @end deftypefn
 

-@deftypefn {Function} {} RINDEX (@var{haystack}, @var{needle}, @var{divisor})
-Divides @var{needle} into parts, each with length @var{divisor}.
+@deftypefn {Function} {} RINDEX (@var{haystack}, @var{needle}, @var{needle_len})
+Divides @var{needle} into parts, each with length @var{needle_len}.

 Searches @var{haystack} for the last occurrence of each part, and
 returns the largest value.  Returns 0 if @var{haystack} does not contain
 Searches @var{haystack} for the last occurrence of each part, and
 returns the largest value.  Returns 0 if @var{haystack} does not contain

-any part in @var{needle}.  It is an error if @var{divisor} cannot be
-evenly divided into the length of @var{needle}.  Returns system-missing
+any part in @var{needle}.  It is an error if @var{needle_len} does not
+evenly divide the length of @var{needle}.  Returns system-missing

 if @var{needle} is an empty string.
 @end deftypefn
 
 if @var{needle} is an empty string.
 @end deftypefn
 


@@ -681,10 +645,10 @@ or if @var{padding} does not contain exactly one character.
 @end deftypefn
 
 @cindex strings, trimming
 @end deftypefn
 
 @cindex strings, trimming

-@cindex whitespace, trimming
+@cindex white space, trimming

 @deftypefn {Function} {} RTRIM (@var{string})
 Returns @var{string}, after removing trailing spaces.  Other types of
 @deftypefn {Function} {} RTRIM (@var{string})
 Returns @var{string}, after removing trailing spaces.  Other types of

-whitespace are not removed.
+white space are not removed.

 @end deftypefn
 
 @deftypefn {Function} {} RTRIM (@var{string}, @var{padding})
 @end deftypefn
 
 @deftypefn {Function} {} RTRIM (@var{string}, @var{padding})


@@ -705,9 +669,8 @@ has the value @code{"123.6"}.
 @cindex strings, taking substrings of
 @deftypefn {Function} {} SUBSTR (@var{string}, @var{start})
 Returns a string consisting of the value of @var{string} from position
 @cindex strings, taking substrings of
 @deftypefn {Function} {} SUBSTR (@var{string}, @var{start})
 Returns a string consisting of the value of @var{string} from position

-@var{start} onward.  Returns an empty string if @var{start} is system-missing
-or has a value less than 1 or greater than the number of characters in
-@var{string}.
+@var{start} onward.  Returns an empty string if @var{start} is system-missing,
+less than 1, or greater than the length of @var{string}.

 @end deftypefn
 
 @deftypefn {Function} {} SUBSTR (@var{string}, @var{start}, @var{count})
 @end deftypefn
 
 @deftypefn {Function} {} SUBSTR (@var{string}, @var{start}, @var{count})


@@ -718,8 +681,8 @@ than 1 or greater than the number of characters in @var{string}, or if
 @var{count} is less than 1.  Returns a string shorter than @var{count}
 characters if @var{start} + @var{count} - 1 is greater than the number
 of characters in @var{string}.  Examples: @code{SUBSTR("abcdefg", 3, 2)}
 @var{count} is less than 1.  Returns a string shorter than @var{count}
 characters if @var{start} + @var{count} - 1 is greater than the number
 of characters in @var{string}.  Examples: @code{SUBSTR("abcdefg", 3, 2)}

-has value @code{"cd"}; @code{SUBSTR("Ben Pfaff", 5, 10)} has the value
-@code{"Pfaff"}.
+has value @code{"cd"}; @code{SUBSTR("nonsense", 4, 10)} has the value
+@code{"sense"}.

 @end deftypefn
 
 @cindex case conversion
 @end deftypefn
 
 @cindex case conversion


@@ -728,51 +691,28 @@ has value @code{"cd"}; @code{SUBSTR("Ben Pfaff", 5, 10)} has the value
 Returns @var{string}, changing lowercase letters to uppercase letters.
 @end deftypefn
 
 Returns @var{string}, changing lowercase letters to uppercase letters.
 @end deftypefn
 

-@node Time & Date, Miscellaneous Functions, String Functions, Functions
+@node Time and Date

 @subsection Time & Date Functions
 @cindex functions, time & date
 @cindex times
 @cindex dates
 
 @subsection Time & Date Functions
 @cindex functions, time & date
 @cindex times
 @cindex dates
 

-@cindex dates, legal range of
-The legal range of dates for use in PSPP is 15 Oct 1582
-through 31 Dec 19999.
-
-@cindex arguments, invalid
-@cindex invalid arguments
-@quotation
-@strong{Please note:} Most time & date extraction functions will accept
-invalid arguments:
-
-@itemize @bullet
-@item
-Negative numbers in PSPP time format.
-@item
-Numbers less than 86,400 in PSPP date format.
-@end itemize
-
-However, sensible results are not guaranteed for these invalid values.
-The given equivalents for these functions are definitely not guaranteed
-for invalid values.
-@end quotation
-
-@quotation
-@strong{Please note also:} The time & date construction
-functions @strong{do} produce reasonable and useful results for
-out-of-range values; these are not considered invalid.
-@end quotation
+@cindex dates, valid
+For compatibility, PSPP considers dates before 15 Oct 1582 invalid.
+Most time and date functions will not accept earlier dates.

 
 @menu
 
 @menu

-* Time & Date Concepts::        How times & dates are defined and represented
+* Time and Date Concepts::      How times & dates are defined and represented

 * Time Construction::           TIME.@{DAYS HMS@}
 * Time Extraction::             CTIME.@{DAYS HOURS MINUTES SECONDS@}
 * Date Construction::           DATE.@{DMY MDY MOYR QYR WKYR YRDAY@}
 * Date Extraction::             XDATE.@{DATE HOUR JDAY MDAY MINUTE MONTH
                                        QUARTER SECOND TDAY TIME WEEK
                                        WKDAY YEAR@}
 * Time Construction::           TIME.@{DAYS HMS@}
 * Time Extraction::             CTIME.@{DAYS HOURS MINUTES SECONDS@}
 * Date Construction::           DATE.@{DMY MDY MOYR QYR WKYR YRDAY@}
 * Date Extraction::             XDATE.@{DATE HOUR JDAY MDAY MINUTE MONTH
                                        QUARTER SECOND TDAY TIME WEEK
                                        WKDAY YEAR@}

+* Time and Date Arithmetic::    DATEDIFF DATESUM

 @end menu
 
 @end menu
 

-@node Time & Date Concepts, Time Construction, Time & Date, Time & Date
+@node Time and Date Concepts

 @subsubsection How times & dates are defined and represented
 
 @cindex time, concepts
 @subsubsection How times & dates are defined and represented
 
 @cindex time, concepts


@@ -786,16 +726,14 @@ Thus, the following intervals correspond with the numeric values given:
           1 hour                          3,600
           1 day, 3 hours, 10 seconds     97,210
           40 days                     3,456,000
           1 hour                          3,600
           1 day, 3 hours, 10 seconds     97,210
           40 days                     3,456,000

-          10010 d, 14 min, 24 s     864,864,864

 @end example
 
 @cindex dates, concepts
 @cindex time, instants of
 @end example
 
 @cindex dates, concepts
 @cindex time, instants of

-A @dfn{date}, on the other hand, is a particular instant in the past or
-the future.  PSPP represents a date as a number of seconds after the
-midnight that separated 8 Oct 1582 and 9 Oct 1582.  (Please note that 15
-Oct 1582 immediately followed 9 Oct 1582.)  Thus, the midnights before
-the dates given below correspond with the numeric PSPP dates given:
+A @dfn{date}, on the other hand, is a particular instant in the past
+or the future.  PSPP represents a date as a number of seconds since
+midnight preceding 14 Oct 1582.  Because midnight preceding the dates
+given below correspond with the numeric PSPP dates given:

 
 @example
               15 Oct 1582                86,400
 
 @example
               15 Oct 1582                86,400


@@ -805,63 +743,30 @@ the dates given below correspond with the numeric PSPP dates given:
               24 Aug 1995        13,028,601,600
 @end example
 
               24 Aug 1995        13,028,601,600
 @end example
 

-@cindex time, mathematical properties of
-@cindex mathematics, applied to times & dates
-@cindex dates, mathematical properties of
-@noindent
-Please note: 
-
-@itemize @bullet
-@item
-A time may be added to, or subtracted from, a date, resulting in a date.
-
-@item
-The difference of two dates may be taken, resulting in a time.  
-
-@item 
-Two times may be added to, or subtracted from, each other, resulting in
-a time.
-@end itemize
-
-(Adding two dates does not produce a useful result.)
-
-Since times and dates are merely numbers, the ordinary addition and
-subtraction operators are employed for these purposes.
-
-@quotation
-@strong{Please note:} Many dates and times have extremely large
-values---just look at the values above.  Thus, it is not a good idea to
-take powers of these values; also, the accuracy of some procedures may
-be affected.  If necessary, convert times or dates in seconds to some
-other unit, like days or years, before performing analysis.
-@end quotation
-
-@node Time Construction, Time Extraction, Time & Date Concepts, Time & Date
+@node Time Construction

 @subsubsection Functions that Produce Times
 @cindex times, constructing
 @cindex constructing times
 
 @subsubsection Functions that Produce Times
 @cindex times, constructing
 @cindex constructing times
 

-These functions take numeric arguments and produce numeric results in
-PSPP time format.
+These functions take numeric arguments and return numeric values that
+represent times.

 
 @cindex days
 @cindex time, in days
 @deftypefn {Function} {} TIME.DAYS (@var{ndays})
 
 @cindex days
 @cindex time, in days
 @deftypefn {Function} {} TIME.DAYS (@var{ndays})

-Results in a time value corresponding to @var{ndays} days.
-(@code{TIME.DAYS(@var{x})} is equivalent to @code{@var{x} * 60 * 60 *
-24}.)
+Returns a time corresponding to @var{ndays} days.

 @end deftypefn
 
 @cindex hours-minutes-seconds
 @cindex time, in hours-minutes-seconds
 @deftypefn {Function} {} TIME.HMS (@var{nhours}, @var{nmins}, @var{nsecs})
 @end deftypefn
 
 @cindex hours-minutes-seconds
 @cindex time, in hours-minutes-seconds
 @deftypefn {Function} {} TIME.HMS (@var{nhours}, @var{nmins}, @var{nsecs})

-Results in a time value corresponding to @var{nhours} hours, @var{nmins}
-minutes, and @var{nsecs} seconds.  (@code{TIME.HMS(@var{h}, @var{m},
-@var{s})} is equivalent to @code{@var{h}*60*60 + @var{m}*60 +
-@var{s}}.)
+Returns a time corresponding to @var{nhours} hours, @var{nmins}
+minutes, and @var{nsecs} seconds.  The arguments may not have mixed
+signs: if any of them are positive, then none may be negative, and
+vice versa.  

 @end deftypefn
 
 @end deftypefn
 

-@node Time Extraction, Date Construction, Time Construction, Time & Date
+@node Time Extraction

 @subsubsection Functions that Examine Times
 @cindex extraction, of time
 @cindex time examination
 @subsubsection Functions that Examine Times
 @cindex extraction, of time
 @cindex time examination


@@ -875,21 +780,18 @@ give numeric results.
 @cindex time, in days
 @deftypefn {Function} {} CTIME.DAYS (@var{time})
 Results in the number of days and fractional days in @var{time}.
 @cindex time, in days
 @deftypefn {Function} {} CTIME.DAYS (@var{time})
 Results in the number of days and fractional days in @var{time}.

-(@code{CTIME.DAYS(@var{x})} is equivalent to @code{@var{x}/60/60/24}.)

 @end deftypefn
 
 @cindex hours
 @cindex time, in hours
 @deftypefn {Function} {} CTIME.HOURS (@var{time})
 Results in the number of hours and fractional hours in @var{time}.
 @end deftypefn
 
 @cindex hours
 @cindex time, in hours
 @deftypefn {Function} {} CTIME.HOURS (@var{time})
 Results in the number of hours and fractional hours in @var{time}.

-(@code{CTIME.HOURS(@var{x})} is equivalent to @code{@var{x}/60/60}.)

 @end deftypefn
 
 @cindex minutes
 @cindex time, in minutes
 @deftypefn {Function} {} CTIME.MINUTES (@var{time})
 Results in the number of minutes and fractional minutes in @var{time}.
 @end deftypefn
 
 @cindex minutes
 @cindex time, in minutes
 @deftypefn {Function} {} CTIME.MINUTES (@var{time})
 Results in the number of minutes and fractional minutes in @var{time}.

-(@code{CTIME.MINUTES(@var{x})} is equivalent to @code{@var{x}/60}.)

 @end deftypefn
 
 @cindex seconds
 @end deftypefn
 
 @cindex seconds


@@ -900,25 +802,30 @@ Results in the number of seconds and fractional seconds in @var{time}.
 equivalent to @code{@var{x}}.)
 @end deftypefn
 
 equivalent to @code{@var{x}}.)
 @end deftypefn
 

-@node Date Construction, Date Extraction, Time Extraction, Time & Date
+@node Date Construction

 @subsubsection Functions that Produce Dates
 @cindex dates, constructing
 @cindex constructing dates
 
 @cindex arguments, of date construction functions
 @subsubsection Functions that Produce Dates
 @cindex dates, constructing
 @cindex constructing dates
 
 @cindex arguments, of date construction functions

-These functions take numeric arguments and give numeric results in the
-PSPP date format.  Arguments taken by these functions are:
+These functions take numeric arguments and give numeric results that
+represent dates.  Arguments taken by these functions are:

 
 @table @var
 @item day
 
 @table @var
 @item day

-Refers to a day of the month between 1 and 31.
+Refers to a day of the month between 1 and 31.  Day 0 is also accepted
+and refers to the final day of the previous month.  Days 29, 30, and
+31 are accepted even in months that have fewer days and refer to a day
+near the beginning of the following month.

 
 @item month
 
 @item month

-Refers to a month of the year between 1 and 12.
+Refers to a month of the year between 1 and 12.  Months 0 and 13 are
+also accepted and refer to the last month of the preceding year and
+the first month of the following year, respectively.

 
 @item quarter
 Refers to a quarter of the year between 1 and 4.  The quarters of the
 
 @item quarter
 Refers to a quarter of the year between 1 and 4.  The quarters of the

-year begin on the first days of months 1, 4, 7, and 10.
+year begin on the first day of months 1, 4, 7, and 10.

 
 @item week
 Refers to a week of the year between 1 and 53.
 
 @item week
 Refers to a week of the year between 1 and 53.


@@ -927,7 +834,9 @@ Refers to a week of the year between 1 and 53.
 Refers to a day of the year between 1 and 366.
 
 @item year
 Refers to a day of the year between 1 and 366.
 
 @item year

-Refers to a year between 1582 and 19999.
+Refers to a year, 1582 or greater.  Years between 0 and 99 are treated
+according to the epoch set on SET EPOCH, by default beginning 69 years
+before the current date (@pxref{SET EPOCH}).

 @end table
 
 @cindex arguments, invalid
 @end table
 
 @cindex arguments, invalid


@@ -967,11 +876,11 @@ day of week @var{week} of year @var{year}.
 @cindex year-day
 @cindex dates, year-day
 @deftypefn {Function} {} DATE.YRDAY (@var{year}, @var{yday})
 @cindex year-day
 @cindex dates, year-day
 @deftypefn {Function} {} DATE.YRDAY (@var{year}, @var{yday})

-Results in a date value corresponding to the midnight before day
+Results in a date value corresponding to the day

 @var{yday} of year @var{year}.
 @end deftypefn
 
 @var{yday} of year @var{year}.
 @end deftypefn
 

-@node Date Extraction,  , Date Construction, Time & Date
+@node Date Extraction

 @subsubsection Functions that Examine Dates
 @cindex extraction, of dates
 @cindex date examination
 @subsubsection Functions that Examine Dates
 @cindex extraction, of dates
 @cindex date examination


@@ -999,8 +908,6 @@ For a time, results in the time corresponding to the number of whole
 days @var{date-or-time} includes.  For a date, results in the date
 corresponding to the latest midnight at or before @var{date-or-time};
 that is, gives the date that @var{date-or-time} is in.
 days @var{date-or-time} includes.  For a date, results in the date
 corresponding to the latest midnight at or before @var{date-or-time};
 that is, gives the date that @var{date-or-time} is in.

-(XDATE.DATE(@var{x}) is equivalent to TRUNC(@var{x}/86400)*86400.)
-Applying this function to a time is a non-portable feature.

 @end deftypefn
 
 @cindex hours
 @end deftypefn
 
 @cindex hours


@@ -1010,9 +917,7 @@ Applying this function to a time is a non-portable feature.
 For a time, results in the number of whole hours beyond the number of
 whole days represented by @var{date-or-time}.  For a date, results in
 the hour (as an integer between 0 and 23) corresponding to
 For a time, results in the number of whole hours beyond the number of
 whole days represented by @var{date-or-time}.  For a date, results in
 the hour (as an integer between 0 and 23) corresponding to

-@var{date-or-time}.  (XDATE.HOUR(@var{x}) is equivalent to
-MOD(TRUNC(@var{x}/3600),24))  Applying this function to a time is a
-non-portable feature.
+@var{date-or-time}.  

 @end deftypefn
 
 @cindex day of the year
 @end deftypefn
 
 @cindex day of the year


@@ -1034,9 +939,7 @@ corresponding to @var{date}.
 @cindex time, in minutes
 @deftypefn {Function} {} XDATE.MINUTE (@var{time-or-date})
 Results in the number of minutes (as an integer between 0 and 59) after
 @cindex time, in minutes
 @deftypefn {Function} {} XDATE.MINUTE (@var{time-or-date})
 Results in the number of minutes (as an integer between 0 and 59) after

-the last hour in @var{time-or-date}.  (XDATE.MINUTE(@var{x}) is
-equivalent to MOD(TRUNC(@var{x}/60),60)) Applying this function to a
-time is a non-portable feature.
+the last hour in @var{time-or-date}. 

 @end deftypefn
 
 @cindex months
 @end deftypefn
 
 @cindex months


@@ -1059,24 +962,20 @@ corresponding to @var{date}.
 @deftypefn {Function} {} XDATE.SECOND (@var{time-or-date})
 Results in the number of whole seconds after the last whole minute (as
 an integer between 0 and 59) in @var{time-or-date}.
 @deftypefn {Function} {} XDATE.SECOND (@var{time-or-date})
 Results in the number of whole seconds after the last whole minute (as
 an integer between 0 and 59) in @var{time-or-date}.

-(XDATE.SECOND(@var{x}) is equivalent to MOD(@var{x}, 60).)  Applying
-this function to a time is a non-portable feature.

 @end deftypefn
 
 @cindex days
 @cindex times, in days
 @end deftypefn
 
 @cindex days
 @cindex times, in days

-@deftypefn {Function} {} XDATE.TDAY (@var{time})
-Results in the number of whole days (as an integer) in @var{time}.
-(XDATE.TDAY(@var{x}) is equivalent to TRUNC(@var{x}/86400).)
+@deftypefn {Function} {} XDATE.TDAY (@var{date})
+Results in the number of whole days from 14 Oct 1582 to @var{date}.

 @end deftypefn
 
 @cindex time
 @cindex dates, time of day
 @deftypefn {Function} {} XDATE.TIME (@var{date})
 Results in the time of day at the instant corresponding to @var{date},
 @end deftypefn
 
 @cindex time
 @cindex dates, time of day
 @deftypefn {Function} {} XDATE.TIME (@var{date})
 Results in the time of day at the instant corresponding to @var{date},

-in PSPP time format.  This is the number of seconds since
-midnight on the day corresponding to @var{date}.  (XDATE.TIME(@var{x}) is
-equivalent to TRUNC(@var{x}/86400)*86400.)
+as a time value.  This is the number of seconds since
+midnight on the day corresponding to @var{date}.

 @end deftypefn
 
 @cindex week
 @end deftypefn
 
 @cindex week


@@ -1092,111 +991,503 @@ corresponding to @var{date}.
 @cindex dates, in weekdays
 @deftypefn {Function} {} XDATE.WKDAY (@var{date})
 Results in the day of week (as an integer between 1 and 7) corresponding
 @cindex dates, in weekdays
 @deftypefn {Function} {} XDATE.WKDAY (@var{date})
 Results in the day of week (as an integer between 1 and 7) corresponding

-to @var{date}.  The days of the week are:
-
-@table @asis
-@item 1
-Sunday
-@item 2
-Monday
-@item 3
-Tuesday
-@item 4
-Wednesday
-@item 5
-Thursday
-@item 6
-Friday
-@item 7
-Saturday
-@end table
+to @var{date}, where 1 represents Sunday.

 @end deftypefn
 
 @cindex years
 @cindex dates, in years
 @deftypefn {Function} {} XDATE.YEAR (@var{date})
 @end deftypefn
 
 @cindex years
 @cindex dates, in years
 @deftypefn {Function} {} XDATE.YEAR (@var{date})

-Returns the year (as an integer between 1582 and 19999) corresponding to
+Returns the year (as an integer 1582 or greater) corresponding to

 @var{date}.
 @end deftypefn
 
 @var{date}.
 @end deftypefn
 

-@node Miscellaneous Functions, Functions Not Implemented, Time & Date, Functions
+@node Time and Date Arithmetic
+@subsubsection Time and Date Arithmetic
+
+@cindex time, mathematical properties of
+@cindex mathematics, applied to times & dates
+@cindex dates, mathematical properties of
+@noindent
+Ordinary arithmetic operations on dates and times often produce
+sensible results.  Adding a time to, or subtracting one from, a date
+produces a new date that much earlier or later.  The difference of two
+dates yields the time between those dates.  Adding two times produces
+the combined time.  Multiplying a time by a scalar produces a time
+that many times longer.  Since times and dates are just numbers, the
+ordinary addition and subtraction operators are employed for these
+purposes.
+
+Adding two dates does not produce a useful result.
+
+Dates and times may have very large values.  Thus,
+it is not a good idea to take powers of these values; also, the
+accuracy of some procedures may be affected.  If necessary, convert
+times or dates in seconds to some other unit, like days or years,
+before performing analysis.
+
+PSPP supplies a few functions for date arithmetic:
+
+@deftypefn {Function} {} DATEDIFF (@var{date2}, @var{date1}, @var{unit})
+Returns the span of time from @var{date1} to @var{date2} in terms of
+@var{unit}, which must be a quoted string, one of @samp{years},
+@samp{quarters}, @samp{months}, @samp{weeks}, @samp{days},
+@samp{hours}, @samp{minutes}, and @samp{seconds}.  The result is an
+integer, truncated toward zero.
+
+One year is considered to span from a given date to the same month,
+day, and time of day the next year.  Thus, from Jan.@tie{}1 of one
+year to Jan.@tie{}1 the next year is considered to be a full year, but
+Feb.@tie{}29 of a leap year to the following Feb.@tie{}28 is not.
+Similarly, one month spans from a given day of the month to the same
+day of the following month.  Thus, there is never a full month from
+Jan.@tie{}31 of a given year to any day in the following February.
+@end deftypefn
+
+@deftypefn {Function} {} DATESUM (@var{date}, @var{quantity}, @var{unit}[, @var{method}])
+Returns @var{date} advanced by the given @var{quantity} of the
+specified @var{unit}, which must be one of the strings @samp{years},
+@samp{quarters}, @samp{months}, @samp{weeks}, @samp{days},
+@samp{hours}, @samp{minutes}, and @samp{seconds}.
+
+When @var{unit} is @samp{years}, @samp{quarters}, or @samp{months},
+only the integer part of @var{quantity} is considered.  Adding one of
+these units can cause the day of the month to exceed the number of
+days in the month.  In this case, the @var{method} comes into
+play: if it is omitted or specified as @samp{closest} (as a quoted
+string), then the resulting day is the last day of the month;
+otherwise, if it is specified as @samp{rollover}, then the extra days
+roll over into the following month.
+
+When @var{unit} is @samp{weeks}, @samp{days}, @samp{hours},
+@samp{minutes}, or @samp{seconds}, the @var{quantity} is not rounded
+to an integer and @var{method}, if specified, is ignored.
+@end deftypefn
+
+@node Miscellaneous Functions

 @subsection Miscellaneous Functions
 @cindex functions, miscellaneous
 
 @subsection Miscellaneous Functions
 @cindex functions, miscellaneous
 

-Miscellaneous functions take various arguments and produce various
-results.
-

 @cindex cross-case function
 @cindex function, cross-case
 @cindex cross-case function
 @cindex function, cross-case

-@deftypefn {Function} {} LAG (@var{variable})
+@deftypefn {Function} {} LAG (@var{variable}[, @var{n}])

 @anchor{LAG}
 @anchor{LAG}

+

 @var{variable} must be a numeric or string variable name.  @code{LAG}
 @var{variable} must be a numeric or string variable name.  @code{LAG}

-results in the value of that variable for the case before the current
-one.  In case-selection procedures, @code{LAG} results in the value of
-the variable for the last case selected.  Results in system-missing (for
-numeric variables) or blanks (for string variables) for the first case
-or before any cases are selected.
-@end deftypefn
+yields the value of that variable for the case @var{n} before the
+current one.  Results in system-missing (for numeric variables) or
+blanks (for string variables) for the first @var{n} cases.
+
+@code{LAG} obtains values from the cases that become the new active file
+after a procedure executes.  Thus, @code{LAG} will not return values
+from cases dropped by transformations such as @cmd{SELECT IF}, and
+transformations like @cmd{COMPUTE} that modify data will change the
+values returned by @code{LAG}.  These are both the case whether these
+transformations precede or follow the use of @code{LAG}.

 
 

-@deftypefn {Function} {} LAG (@var{variable}, @var{ncases})
-@var{variable} must be a numeric or string variable name.  @var{ncases}
-must be a small positive constant integer, although there is no explicit
-limit.  (Use of a large value for @var{ncases} will increase memory
-consumption, since PSPP must keep @var{ncases} cases in memory.)
-@code{LAG (@var{variable}, @var{ncases}} results in the value of
-@var{variable} that is @var{ncases} before the case currently being
-processed.  See @code{LAG (@var{variable})} above for more details.
+If @code{LAG} is used before @cmd{TEMPORARY}, then the values it returns
+are those in cases just before @cmd{TEMPORARY}.  @code{LAG} may not be
+used after @cmd{TEMPORARY}.
+
+If omitted, @var{ncases} defaults to 1.  Otherwise, @var{ncases} must
+be a small positive constant integer.  There is no explicit limit, but
+use of a large value will increase memory consumption.

 @end deftypefn
 
 @cindex date, Julian
 @cindex Julian date
 @deftypefn {Function} {} YRMODA (@var{year}, @var{month}, @var{day})
 @end deftypefn
 
 @cindex date, Julian
 @cindex Julian date
 @deftypefn {Function} {} YRMODA (@var{year}, @var{month}, @var{day})

-@var{year} is a year between 0 and 199 or 1582 and 19999.  @var{month} is
-a month between 1 and 12.  @var{day} is a day between 1 and 31.  If
-@var{month} or @var{day} is out-of-range, it changes the next higher
-unit.  For instance, a @var{day} of 0 refers to the last day of the
-previous month, and a @var{month} of 13 refers to the first month of the
-next year.  @var{year} must be in range.  If @var{year} is between 0 and
-199, 1900 is added.  @var{year}, @var{month}, and @var{day} must all be
-integers.
+@var{year} is a year, either between 0 and 99 or at least 1582.
+Unlike other PSPP date functions, years between 0 and 99 always
+correspond to 1900 through 1999.  @var{month} is a month between 1 and
+13.  @var{day} is a day between 0 and 31.  A @var{day} of 0 refers to
+the last day of the previous month, and a @var{month} of 13 refers to
+the first month of the next year.  @var{year} must be in range.
+@var{year}, @var{month}, and @var{day} must all be integers.

 
 @code{YRMODA} results in the number of days between 15 Oct 1582 and
 the date specified, plus one.  The date passed to @code{YRMODA} must be
 on or after 15 Oct 1582.  15 Oct 1582 has a value of 1.
 @end deftypefn
 
 
 @code{YRMODA} results in the number of days between 15 Oct 1582 and
 the date specified, plus one.  The date passed to @code{YRMODA} must be
 on or after 15 Oct 1582.  15 Oct 1582 has a value of 1.
 @end deftypefn
 

-@node Functions Not Implemented,  , Miscellaneous Functions, Functions
-@subsection Functions Not Implemented
-@cindex functions, not implemented
-@cindex not implemented
-@cindex features, not implemented
+@cindex value label
+@deftypefn {Function} VALUELABEL (@var{variable})
+Returns a string matching the label associated with the current value
+of @var{variable}.  If the current value of @var{variable} has no
+associated label, then this function returns the empty string.
+@var{variable} may be a numeric or string variable.
+@end deftypefn

 
 

-These functions are not yet implemented and thus not yet documented,
-since it's a hassle.
+@node Statistical Distribution Functions
+@subsection Statistical Distribution Functions

 
 

-@findex CDF.xxx
-@findex CDFNORM
-@findex IDF.xxx
-@findex NCDF.xxx
-@findex PROBIT
-@findex RV.xxx
+PSPP can calculate several functions of standard statistical
+distributions.  These functions are named systematically based on the
+function and the distribution.  The table below describes the
+statistical distribution functions in general:

 
 

-@itemize @bullet
-@item
-@code{CDF.xxx}
-@item
-@code{CDFNORM}
-@item
-@code{IDF.xxx}
-@item
-@code{NCDF.xxx}
-@item
-@code{PROBIT}
-@item
-@code{RV.xxx}
-@end itemize
+@table @asis
+@item PDF.@var{dist} (@var{x}[, @var{param}@dots{}])
+Probability density function for @var{dist}.  The domain of @var{x}
+depends on @var{dist}.  For continuous distributions, the result is
+the density of the probability function at @var{x}, and the range is
+nonnegative real numbers.  For discrete distributions, the result is
+the probability of @var{x}.
+
+@item CDF.@var{dist} (@var{x}[, @var{param}@dots{}])
+Cumulative distribution function for @var{dist}, that is, the
+probability that a random variate drawn from the distribution is less
+than @var{x}.  The domain of @var{x} depends @var{dist}.  The result is
+a probability.
+
+@item SIG.@var{dist} (@var{x}[, @var{param}@dots{})
+Tail probability function for @var{dist}, that is, the probability
+that a random variate drawn from the distribution is greater than
+@var{x}.  The domain of @var{x} depends @var{dist}.  The result is a
+probability.  Only a few distributions include an SIG function.
+
+@item IDF.@var{dist} (@var{p}[, @var{param}@dots{}])
+Inverse distribution function for @var{dist}, the value of @var{x} for
+which the CDF would yield @var{p}.  The value of @var{p} is a
+probability.  The range depends on @var{dist} and is identical to the
+domain for the corresponding CDF.
+
+@item RV.@var{dist} ([@var{param}@dots{}])
+Random variate function for @var{dist}.  The range depends on the
+distribution.
+
+@item NPDF.@var{dist} (@var{x}[, @var{param}@dots{}])
+Noncentral probability density function.  The result is the density of
+the given noncentral distribution at @var{x}.  The domain of @var{x}
+depends on @var{dist}.  The range is nonnegative real numbers.  Only a
+few distributions include an NPDF function.
+
+@item NCDF.@var{dist} (@var{x}[, @var{param}@dots{}])
+Noncentral cumulative distribution function for @var{dist}, that is,
+the probability that a random variate drawn from the given noncentral
+distribution is less than @var{x}.  The domain of @var{x} depends
+@var{dist}.  The result is a probability.  Only a few distributions
+include an NCDF function.
+@end table
+
+The individual distributions are described individually below.
+
+@menu
+* Continuous Distributions::    
+* Discrete Distributions::      
+@end menu
+
+@node Continuous Distributions
+@subsubsection Continuous Distributions
+
+The following continuous distributions are available:
+
+@deftypefn {Function} {} PDF.BETA (@var{x})
+@deftypefnx {Function} {} CDF.BETA (@var{x}, @var{a}, @var{b})
+@deftypefnx {Function} {} IDF.BETA (@var{p}, @var{a}, @var{b})
+@deftypefnx {Function} {} RV.BETA (@var{a}, @var{b})
+@deftypefnx {Function} {} NPDF.BETA (@var{x}, @var{a}, @var{b}, @var{lambda})
+@deftypefnx {Function} {} NCDF.BETA (@var{x}, @var{a}, @var{b}, @var{lambda})
+Beta distribution with shape parameters @var{a} and @var{b}.  The
+noncentral distribution takes an additional parameter @var{lambda}.
+Constraints: @var{a} > 0, @var{b} > 0, @var{lambda} >= 0, 0 <= @var{x}
+<= 1, 0 <= @var{p} <= 1.
+@end deftypefn
+
+@deftypefn {Function} {} PDF.BVNOR (@var{x0}, @var{x1}, @var{rho})
+@deftypefnx {Function} {} CDF.VBNOR (@var{x0}, @var{x1}, @var{rho})
+Bivariate normal distribution of two standard normal variables with
+correlation coefficient @var{rho}.  Two variates @var{x0} and @var{x1}
+must be provided.  Constraints: 0 <= @var{rho} <= 1, 0 <= @var{p} <= 1.
+@end deftypefn
+
+@deftypefn {Function} {} PDF.CAUCHY (@var{x}, @var{a}, @var{b})
+@deftypefnx {Function} {} CDF.CAUCHY (@var{x}, @var{a}, @var{b})
+@deftypefnx {Function} {} IDF.CAUCHY (@var{p}, @var{a}, @var{b})
+@deftypefnx {Function} {} RV.CAUCHY (@var{a}, @var{b})
+Cauchy distribution with location parameter @var{a} and scale
+parameter @var{b}.  Constraints: @var{b} > 0, 0 < @var{p} < 1.
+@end deftypefn
+
+@deftypefn {Function} {} PDF.CHISQ (@var{x}, @var{df})
+@deftypefnx {Function} {} CDF.CHISQ (@var{x}, @var{df})
+@deftypefnx {Function} {} SIG.CHISQ (@var{x}, @var{df})
+@deftypefnx {Function} {} IDF.CHISQ (@var{p}, @var{df})
+@deftypefnx {Function} {} RV.CHISQ (@var{df})
+@deftypefnx {Function} {} NPDF.CHISQ (@var{x}, @var{df}, @var{lambda})
+@deftypefnx {Function} {} NCDF.CHISQ (@var{x}, @var{df}, @var{lambda})
+Chi-squared distribution with @var{df} degrees of freedom.  The
+noncentral distribution takes an additional parameter @var{lambda}.
+Constraints: @var{df} > 0, @var{lambda} > 0, @var{x} >= 0, 0 <=
+@var{p} < 1.
+@end deftypefn
+
+@deftypefn {Function} {} PDF.EXP (@var{x}, @var{a})
+@deftypefnx {Function} {} CDF.EXP (@var{x}, @var{a})
+@deftypefnx {Function} {} IDF.EXP (@var{p}, @var{a})
+@deftypefnx {Function} {} RV.EXP (@var{a})
+Exponential distribution with scale parameter @var{a}.  The inverse of
+@var{a} represents the rate of decay.  Constraints: @var{a} > 0,
+@var{x} >= 0, 0 <= @var{p} < 1.
+@end deftypefn
+
+@deftypefn {Function} {} PDF.XPOWER (@var{x}, @var{a}, @var{b})
+@deftypefnx {Function} {} RV.XPOWER (@var{a}, @var{b})
+Exponential power distribution with positive scale parameter @var{a}
+and nonnegative power parameter @var{b}.  Constraints: @var{a} > 0,
+@var{b} >= 0, @var{x} >= 0, 0 <= @var{p} <= 1.  This distribution is a
+PSPP extension.
+@end deftypefn
+
+@deftypefn {Function} {} PDF.F (@var{x}, @var{df1}, @var{df2})
+@deftypefnx {Function} {} CDF.F (@var{x}, @var{df1}, @var{df2})
+@deftypefnx {Function} {} SIG.F (@var{x}, @var{df1}, @var{df2})
+@deftypefnx {Function} {} IDF.F (@var{p}, @var{df1}, @var{df2})
+@deftypefnx {Function} {} RV.F (@var{df1}, @var{df2})
+@deftypefnx {Function} {} NPDF.F (@var{x}, @var{df1}, @var{df2}, @var{lambda})
+@deftypefnx {Function} {} NCDF.F (@var{x}, @var{df1}, @var{df2}, @var{lambda})
+F-distribution of two chi-squared deviates with @var{df1} and
+@var{df2} degrees of freedom.  The noncentral distribution takes an
+additional parameter @var{lambda}.  Constraints: @var{df1} > 0,
+@var{df2} > 0, @var{lambda} >= 0, @var{x} >= 0, 0 <= @var{p} < 1.
+@end deftypefn
+
+@deftypefn {Function} {} PDF.GAMMA (@var{x}, @var{a}, @var{b})
+@deftypefnx {Function} {} CDF.GAMMA (@var{x}, @var{a}, @var{b})
+@deftypefnx {Function} {} IDF.GAMMA (@var{p}, @var{a}, @var{b})
+@deftypefnx {Function} {} RV.GAMMA (@var{a}, @var{b})
+Gamma distribution with shape parameter @var{a} and scale parameter
+@var{b}.  Constraints: @var{a} > 0, @var{b} > 0, @var{x} >= 0, 0 <=
+@var{p} < 1.
+@end deftypefn
+
+@deftypefn {Function} {} PDF.HALFNRM (@var{x}, @var{a}, @var{b})
+@deftypefnx {Function} {} CDF.HALFNRM (@var{x}, @var{a}, @var{b})
+@deftypefnx {Function} {} IDF.HALFNRM (@var{p}, @var{a}, @var{b})
+@deftypefnx {Function} {} RV.HALFNRM (@var{a}, @var{b})
+Half-normal distribution with location parameter @var{a} and shape
+parameter @var{b}.  Constraints: @var{b} > 0, 0 < @var{p} < 1.
+@end deftypefn
+
+@deftypefn {Function} {} PDF.IGAUSS (@var{x}, @var{a}, @var{b})
+@deftypefnx {Function} {} CDF.IGAUSS (@var{x}, @var{a}, @var{b})
+@deftypefnx {Function} {} IDF.IGAUSS (@var{p}, @var{a}, @var{b})
+@deftypefnx {Function} {} RV.IGAUSS (@var{a}, @var{b})
+Inverse Gaussian distribution with parameters @var{a} and @var{b}.
+Constraints: @var{a} > 0, @var{b} > 0, @var{x} > 0, 0 <= @var{p} < 1.
+@end deftypefn
+
+@deftypefn {Function} {} PDF.LANDAU (@var{x})
+@deftypefnx {Function} {} RV.LANDAU ()
+Landau distribution.
+@end deftypefn
+
+@deftypefn {Function} {} PDF.LAPLACE (@var{x}, @var{a}, @var{b})
+@deftypefnx {Function} {} CDF.LAPLACE (@var{x}, @var{a}, @var{b})
+@deftypefnx {Function} {} IDF.LAPLACE (@var{p}, @var{a}, @var{b})
+@deftypefnx {Function} {} RV.LAPLACE (@var{a}, @var{b})
+Laplace distribution with location parameter @var{a} and scale
+parameter @var{b}.  Constraints: @var{b} > 0, 0 < @var{p} < 1.
+@end deftypefn
+
+@deftypefn {Function} {} RV.LEVY (@var{c}, @var{alpha})
+Levy symmetric alpha-stable distribution with scale @var{c} and
+exponent @var{alpha}.  Constraints: 0 < @var{alpha} <= 2.
+@end deftypefn
+
+@deftypefn {Function} {} RV.LVSKEW (@var{c}, @var{alpha}, @var{beta})
+Levy skew alpha-stable distribution with scale @var{c}, exponent
+@var{alpha}, and skewness parameter @var{beta}.  Constraints: 0 <
+@var{alpha} <= 2, -1 <= @var{beta} <= 1.
+@end deftypefn
+
+@deftypefn {Function} {} PDF.LOGISTIC (@var{x}, @var{a}, @var{b})
+@deftypefnx {Function} {} CDF.LOGISTIC (@var{x}, @var{a}, @var{b})
+@deftypefnx {Function} {} IDF.LOGISTIC (@var{p}, @var{a}, @var{b})
+@deftypefnx {Function} {} RV.LOGISTIC (@var{a}, @var{b})
+Logistic distribution with location parameter @var{a} and scale
+parameter @var{b}.  Constraints: @var{b} > 0, 0 < @var{p} < 1.
+@end deftypefn
+
+@deftypefn {Function} {} PDF.LNORMAL (@var{x}, @var{a}, @var{b})
+@deftypefnx {Function} {} CDF.LNORMAL (@var{x}, @var{a}, @var{b})
+@deftypefnx {Function} {} IDF.LNORMAL (@var{p}, @var{a}, @var{b})
+@deftypefnx {Function} {} RV.LNORMAL (@var{a}, @var{b})
+Lognormal distribution with parameters @var{a} and @var{b}.
+Constraints: @var{a} > 0, @var{b} > 0, @var{x} >= 0, 0 <= @var{p} < 1.
+@end deftypefn
+
+@deftypefn {Function} {} PDF.NORMAL (@var{x}, @var{mu}, @var{sigma})
+@deftypefnx {Function} {} CDF.NORMAL (@var{x}, @var{mu}, @var{sigma})
+@deftypefnx {Function} {} IDF.NORMAL (@var{p}, @var{mu}, @var{sigma})
+@deftypefnx {Function} {} RV.NORMAL (@var{mu}, @var{sigma})
+Normal distribution with mean @var{mu} and standard deviation
+@var{sigma}.  Constraints: @var{b} > 0, 0 < @var{p} < 1.  Three
+additional functions are available as shorthand:
+
+@deftypefn {Function} {} CDFNORM (@var{x})
+Equivalent to CDF.NORMAL(@var{x}, 0, 1).
+@end deftypefn
+
+@deftypefn {Function} {} PROBIT (@var{p})
+Equivalent to IDF.NORMAL(@var{p}, 0, 1).
+@end deftypefn
+
+@deftypefn {Function} {} NORMAL (@var{sigma})
+Equivalent to RV.NORMAL(0, @var{sigma}).
+@end deftypefn
+@end deftypefn
+
+@deftypefn {Function} {} PDF.NTAIL (@var{x}, @var{a}, @var{sigma})
+@deftypefnx {Function} {} RV.NTAIL (@var{a}, @var{sigma})
+Normal tail distribution with lower limit @var{a} and standard
+deviation @var{sigma}.  This distribution is a PSPP extension.
+Constraints: @var{a} > 0, @var{x} > @var{a}, 0 < @var{p} < 1.
+@end deftypefn
+
+@deftypefn {Function} {} PDF.PARETO (@var{x}, @var{a}, @var{b})
+@deftypefnx {Function} {} CDF.PARETO (@var{x}, @var{a}, @var{b})
+@deftypefnx {Function} {} IDF.PARETO (@var{p}, @var{a}, @var{b})
+@deftypefnx {Function} {} RV.PARETO (@var{a}, @var{b})
+Pareto distribution with threshold parameter @var{a} and shape
+parameter @var{b}.  Constraints: @var{a} > 0, @var{b} > 0, @var{x} >=
+@var{a}, 0 <= @var{p} < 1.
+@end deftypefn
+
+@deftypefn {Function} {} PDF.RAYLEIGH (@var{x}, @var{sigma})
+@deftypefnx {Function} {} CDF.RAYLEIGH (@var{x}, @var{sigma})
+@deftypefnx {Function} {} IDF.RAYLEIGH (@var{p}, @var{sigma})
+@deftypefnx {Function} {} RV.RAYLEIGH (@var{sigma})
+Rayleigh distribution with scale parameter @var{sigma}.  This
+distribution is a PSPP extension.  Constraints: @var{sigma} > 0,
+@var{x} > 0.
+@end deftypefn
+
+@deftypefn {Function} {} PDF.RTAIL (@var{x}, @var{a}, @var{sigma})
+@deftypefnx {Function} {} RV.RTAIL (@var{a}, @var{sigma})
+Rayleigh tail distribution with lower limit @var{a} and scale
+parameter @var{sigma}.  This distribution is a PSPP extension.
+Constraints: @var{a} > 0, @var{sigma} > 0, @var{x} > @var{a}.
+@end deftypefn
+
+@deftypefn {Function} {} CDF.SMOD (@var{x}, @var{a}, @var{b})
+@deftypefnx {Function} {} IDF.SMOD (@var{p}, @var{a}, @var{b})
+Studentized maximum modulus distribution with parameters @var{a} and
+@var{b}.  Constraints: @var{a} > 0, @var{b} > 0, @var{x} > 0, 0 <=
+@var{p} < 1.
+@end deftypefn
+
+@deftypefn {Function} {} CDF.SRANGE (@var{x}, @var{a}, @var{b})
+@deftypefnx {Function} {} IDF.SRANGE (@var{p}, @var{a}, @var{b})
+Studentized range distribution with parameters @var{a} and @var{b}.
+Constraints:  @var{a} >= 1, @var{b} >= 1, @var{x} > 0, 0 <= @var{p} <
+1.
+@end deftypefn
+
+@deftypefn {Function} {} PDF.T (@var{x}, @var{df})
+@deftypefnx {Function} {} CDF.T (@var{x}, @var{df})
+@deftypefnx {Function} {} IDF.T (@var{p}, @var{df})
+@deftypefnx {Function} {} RV.T (@var{df})
+@deftypefnx {Function} {} NPDF.T (@var{x}, @var{df}, @var{lambda})
+@deftypefnx {Function} {} NCDF.T (@var{x}, @var{df}, @var{lambda})
+T-distribution with @var{df} degrees of freedom.  The noncentral
+distribution takes an additional parameter @var{lambda}.  Constraints:
+@var{df} > 0, 0 < @var{p} < 1.
+@end deftypefn
+
+@deftypefn {Function} {} PDF.T1G (@var{x}, @var{a}, @var{b})
+@deftypefnx {Function} {} CDF.T1G (@var{x}, @var{a}, @var{b})
+@deftypefnx {Function} {} IDF.T1G (@var{p}, @var{a}, @var{b})
+Type-1 Gumbel distribution with parameters @var{a} and @var{b}.  This
+distribution is a PSPP extension.  Constraints: 0 < @var{p} < 1.
+@end deftypefn
+
+@deftypefn {Function} {} PDF.T2G (@var{x}, @var{a}, @var{b})
+@deftypefnx {Function} {} CDF.T2G (@var{x}, @var{a}, @var{b})
+@deftypefnx {Function} {} IDF.T2G (@var{p}, @var{a}, @var{b})
+Type-2 Gumbel distribution with parameters @var{a} and @var{b}.  This
+distribution is a PSPP extension.  Constraints: @var{x} > 0, 0 <
+@var{p} < 1.
+@end deftypefn
+
+@deftypefn {Function} {} PDF.UNIFORM (@var{x}, @var{a}, @var{b})
+@deftypefnx {Function} {} CDF.UNIFORM (@var{x}, @var{a}, @var{b})
+@deftypefnx {Function} {} IDF.UNIFORM (@var{p}, @var{a}, @var{b})
+@deftypefnx {Function} {} RV.UNIFORM (@var{a}, @var{b})
+Uniform distribution with parameters @var{a} and @var{b}.
+Constraints: @var{a} <= @var{x} <= @var{b}, 0 <= @var{p} <= 1.  An
+additional function is available as shorthand:
+
+@deftypefn {Function} {} UNIFORM (@var{b})
+Equivalent to RV.UNIFORM(0, @var{b}).
+@end deftypefn
+@end deftypefn
+
+@deftypefn {Function} {} PDF.WEIBULL (@var{x}, @var{a}, @var{b})
+@deftypefnx {Function} {} CDF.WEIBULL (@var{x}, @var{a}, @var{b})
+@deftypefnx {Function} {} IDF.WEIBULL (@var{p}, @var{a}, @var{b})
+@deftypefnx {Function} {} RV.WEIBULL (@var{a}, @var{b})
+Weibull distribution with parameters @var{a} and @var{b}.
+Constraints: @var{a} > 0, @var{b} > 0, @var{x} >= 0, 0 <= @var{p} < 1.
+@end deftypefn
+
+@node Discrete Distributions
+@subsubsection Discrete Distributions
+
+The following discrete distributions are available:
+
+@deftypefn {Function} {} PDF.BERNOULLI (@var{x})
+@deftypefnx {Function} {} CDF.BERNOULLI (@var{x}, @var{p})
+@deftypefnx {Function} {} RV.BERNOULLI (@var{p})
+Bernoulli distribution with probability of success @var{p}.
+Constraints: @var{x} = 0 or 1, 0 <= @var{p} <= 1.
+@end deftypefn
+
+@deftypefn {Function} {} PDF.BINOMIAL (@var{x}, @var{n}, @var{p})
+@deftypefnx {Function} {} CDF.BINOMIAL (@var{x}, @var{n}, @var{p})
+@deftypefnx {Function} {} RV.BINOMIAL (@var{n}, @var{p})
+Binomial distribution with @var{n} trials and probability of success
+@var{p}.  Constraints: integer @var{n} > 0, 0 <= @var{p} <= 1, integer
+@var{x} <= @var{n}.
+@end deftypefn
+
+@deftypefn {Function} {} PDF.GEOM (@var{x}, @var{n}, @var{p})
+@deftypefnx {Function} {} CDF.GEOM (@var{x}, @var{n}, @var{p})
+@deftypefnx {Function} {} RV.GEOM (@var{n}, @var{p})
+Geometric distribution with probability of success @var{p}.
+Constraints: 0 <= @var{p} <= 1, integer @var{x} > 0.
+@end deftypefn
+
+@deftypefn {Function} {} PDF.HYPER (@var{x}, @var{a}, @var{b}, @var{c})
+@deftypefnx {Function} {} CDF.HYPER (@var{x}, @var{a}, @var{b}, @var{c})
+@deftypefnx {Function} {} RV.HYPER (@var{a}, @var{b}, @var{c})
+Hypergeometric distribution when @var{b} objects out of @var{a} are
+drawn and @var{c} of the available objects are distinctive.
+Constraints: integer @var{a} > 0, integer @var{b} <= @var{a}, integer
+@var{c} <= @var{a}, integer @var{x} >= 0.
+@end deftypefn
+
+@deftypefn {Function} {} PDF.LOG (@var{x}, @var{p})
+@deftypefnx {Function} {} RV.LOG (@var{p})
+Logarithmic distribution with probability parameter @var{p}.
+Constraints: 0 <= @var{p} < 1, @var{x} >= 1.
+@end deftypefn
+
+@deftypefn {Function} {} PDF.NEGBIN (@var{x}, @var{n}, @var{p})
+@deftypefnx {Function} {} CDF.NEGBIN (@var{x}, @var{n}, @var{p})
+@deftypefnx {Function} {} RV.NEGBIN (@var{n}, @var{p})
+Negative binomial distribution with number of successes paramter
+@var{n} and probability of success parameter @var{p}.  Constraints:
+integer @var{n} >= 0, 0 < @var{p} <= 1, integer @var{x} >= 1.
+@end deftypefn
+
+@deftypefn {Function} {} PDF.POISSON (@var{x}, @var{mu})
+@deftypefnx {Function} {} CDF.POISSON (@var{x}, @var{mu})
+@deftypefnx {Function} {} RV.POISSON (@var{mu})
+Poisson distribution with mean @var{mu}.  Constraints: @var{mu} > 0,
+integer @var{x} >= 0.
+@end deftypefn

 
 

-@node Order of Operations,  , Functions, Expressions
+@node Order of Operations

 @section Operator Precedence
 @cindex operator precedence
 @cindex precedence, operator
 @section Operator Precedence
 @cindex operator precedence
 @cindex precedence, operator


@@ -1204,11 +1495,10 @@ since it's a hassle.
 @cindex operations, order of
 
 The following table describes operator precedence.  Smaller-numbered
 @cindex operations, order of
 
 The following table describes operator precedence.  Smaller-numbered

-levels in the table have higher precedence.  Within a level, operations
-are performed from left to right, except for level 2 (exponentiation),
-where operations are performed from right to left.  If an operator
-appears in the table in two places (@code{-}), the first occurrence is
-unary, the second is binary.
+levels in the table have higher precedence.  Within a level,
+operations are always performed from left to right.  The first
+occurrence of @samp{-} represents unary negation, the second binary
+subtraction.

 
 @enumerate
 @item
 
 @enumerate
 @item


@@ -1226,4 +1516,3 @@ unary, the second is binary.
 @item
 @code{AND  NOT  OR}
 @end enumerate
 @item
 @code{AND  NOT  OR}
 @end enumerate

-@setfilename ignored