@cindex language, PSPP
@cindex PSPP, language
-@note{PSPP is not even close to completion.
-Only a few statistical procedures are implemented. PSPP
-is a work in progress.}
-
This chapter discusses elements common to many PSPP commands.
Later chapters will describe individual commands in detail.
Strings can be concatenated using @samp{+}, so that @samp{"a" + 'b' +
'c'} is equivalent to @samp{'abc'}. Concatenation is useful for
-splitting a single string across multiple source lines. The maximum
-length of a string, after concatenation, is 255 characters.
+splitting a single string across multiple source lines.
Strings may also be expressed as hexadecimal, octal, or binary
character values by prefixing the initial quote character by @samp{X},
that command being considered part of the previous command.
The period terminating the end of a command is optional but recommended.
-In interactive mode, each command must either be terminated with a period,
-or an empty line must follow the command.
-The use of (@samp{+} and @samp{@minus{}} as continuation characters is not
+In interactive mode, each command must be terminated with a period
+or by a blank line.
+The use of @samp{+} and @samp{@minus{}} as continuation characters is not
permitted.
@node Types of Commands
Variables, whether numeric or string, can have designated
@dfn{user-missing values}. Every user-missing value is an actual value
for that variable. However, most of the time user-missing values are
-treated in the same way as the system-missing value. String variables
-that are wider than a certain width, usually 8 characters (depending on
-computer architecture), cannot have user-missing values.
+treated in the same way as the system-missing value.
For more information on missing values, see the following sections:
@ref{Variables}, @ref{MISSING VALUES}, @ref{Expressions}. See also the