@node Sets of Variables, Input and Output Formats, System Variables, Variables
@subsection Lists of variable names
-@cindex TO convention
-@cindex convention, TO
+@cindex @code{TO} convention
+@cindex convention, @code{TO}
To refer to a set of variables, list their names one after another.
Optionally, their names may be separated by commas. To include a
@node Input and Output Formats, Scratch Variables, Sets of Variables, Variables
@subsection Input and Output Formats
+@cindex formats
An @dfn{input format} describes how to interpret the contents of an
input field as a number or a string. It might specify that the field
contains an ordinary decimal number, a time or date, a number in binary
@node Basic Numeric Formats
@subsubsection Basic Numeric Formats
+@cindex numeric formats
The basic numeric formats are used for input and output of real numbers
in standard or scientific notation. The following table shows an
example of how each format displays positive and negative numbers with
@node Custom Currency Formats
@subsubsection Custom Currency Formats
+@cindex currency formats
The custom currency formats are closely related to the basic numeric
formats, but they allow users to customize the output format. The
SET command configures custom currency formats, using the syntax
@node Binary and Hexadecimal Numeric Formats
@subsubsection Binary and Hexadecimal Numeric Formats
+@cindex binary formats
+@cindex hexadecimal formats
The binary and hexadecimal formats are primarily designed for
compatibility with existing machine formats, not for human readability.
All of them therefore have a F format as default output format. Some of
@node Time and Date Formats
@subsubsection Time and Date Formats
+@cindex time formats
+@cindex date formats
In PSPP, a @dfn{time} is an interval. The time formats translate
between human-friendly descriptions of time intervals and PSPP's
internal representation of time intervals, which is simply the number of
@node String Formats
@subsubsection String Formats
+@cindex string formats
The A and AHEX formats are the only ones that may be assigned to string
variables. Neither format allows any decimal places.
@node Scratch Variables, , Input and Output Formats, Variables
@subsection Scratch Variables
+@cindex scratch variables
Most of the time, variables don't retain their values between cases.
Instead, either they're being read from a data file or the active file,
in which case they assume the value read, or, if created with