+raw-value :=
+ 01 value-mod int32[format] double[x]
+ | 02 value-mod int32[format] double[x]
+ string[varname] string[vallab] (01 | 02 | 03)
+ | 03 string[local] value-mod string[id] string[c] (00 | 01)[type]
+ | 04 value-mod int32[format] string[vallab] string[varname]
+ (01 | 02 | 03) string[s]
+ | 05 value-mod string[varname] string[varlabel] (01 | 02 | 03)
+ | value-mod string[format] int32[n-args] arg*[n-args]
+arg :=
+ i0 value
+ | int32[x] i0 value*[x + 1] /* @r{x > 0} */
+@end example
+
+A @code{value} boils down to a number or a string. There are several
+possibilities, which one can distinguish by the first nonzero byte in
+the encoding:
+
+@table @code
+@item 01
+The numeric value @code{x}, presented to the user formatted according
+to @code{format}, which is in the format described for system files.
+@xref{System File Output Formats}, for details. Most commonly
+@code{format} has width 40 (the maximum).
+
+An @code{x} with the maximum negative double @code{-DBL_MAX}
+represents the system-missing value SYSMIS. (HIGHEST and LOWEST have
+not been observed.) @xref{System File Format}, for more about these
+special values.
+
+@item 02
+Similar to @code{01}, with the additional information that @code{x} is
+a value of variable @code{varname} and has value label @code{vallab}.
+Both @code{varname} and @code{vallab} can be the empty string, the
+latter very commonly.
+
+The meaning of the final byte is unknown. Possibly it is connected to
+whether the value or the label should be displayed.
+
+@item 03
+A text string, in two forms: @code{c} is in English, and sometimes
+abbreviated or obscure, and @code{local} is localized to the user's
+locale. In an English-language locale, the two strings are often the
+same, and in the cases where they differ, @code{local} is more
+appropriate for a user interface, e.g.@: @code{c} of ``Not a PxP table
+for MCN...'' versus @code{local} of ``Computed only for a PxP table,
+where P must be greater than 1.''
+
+@code{c} and @code{local} are always either both empty or both
+nonempty.
+
+@code{id} is a brief identifying string whose form seems to resemble a
+programming language identifier, e.g.@: @code{cumulative_percent} or
+@code{factor_14}. It is not unique.
+
+@code{type} is 00 for text taken from user input, such as syntax
+fragment, expressions, file names, data set names, and 01 for fixed
+text strings such as names of procedures or statistics. In the former
+case, @code{id} is always the empty string; in the latter case,
+@code{id} is still sometimes empty.
+
+@item 04
+The string value @code{s}, presented to the user formatted according
+to @code{format}. The format for a string is not too interesting, and
+clearly invalid formats like A16.39 or A255.127 or A134.1 abound in
+the corpus, so readers should probably ignore the format entirely.
+
+@code{s} is a value of variable @code{varname} and has value label
+@code{vallab}. @code{varname} is never empty but @code{vallab} is
+commonly empty.
+
+The meaning of the final byte is unknown.
+
+@item 05
+Variable @code{varname}, which is rarely observed as empty in the
+corpus, with variable label @code{varlabel}, which is often empty.
+
+The meaning of the final byte is unknown.
+
+@item 31
+@itemx 58
+(These bytes begin a @code{value-mod}.) A format string, analogous to
+@code{printf}, followed by one or more arguments, each of which has
+one or more values. The format string uses the following syntax:
+
+@table @code
+@item \%
+@item \:
+@item \[
+@item \]
+Each of these expands to the character following @samp{\\}. This is
+useful to escape characters that have special meaning in format
+strings. These are effective inside and outside the @code{[@dots{}]}
+syntax forms described below.
+
+@item \n
+Expands to a new-line, inside or outside the @code{[@dots{}]} forms
+described below.
+
+@item ^@var{i}
+Expands to a formatted version of argument @var{i}, which must have
+only a single value. For example, @code{^1} would expand to the first
+argument's @code{value}.
+
+@item [:@var{a}:]@var{i}
+Expands @var{a} for each of the @code{value}s in @var{i}. @var{a}
+should contain one or more @code{^@var{j}} conversions, which are
+drawn from the values for argument @var{i} in order. Some examples
+from the corpus:
+
+@table @code
+@item [:^1:]1
+All of the values for the first argument, concatenated.
+
+@item [:^1\n:]1
+Expands to the values for the first argument, each followed by
+a new-line.
+
+@item [:^1 = ^2:]2
+Expands to @code{@var{x} = @var{y}} where @var{x} is the second
+argument's first value and @var{y} is its second value. (This would
+be used only if the argument has two values. With additional values,
+the second and third values would be directly concatenated, which
+would look funny.)
+@end table
+
+@item [@var{a}:@var{b}:]@var{i}
+This extends the previous form so that the first values are expanded
+using @var{a} and later values are expanded using @var{b}. For an
+unknown reason, within @var{a} the @code{^@var{j}} conversions are
+instead written as @code{%@var{j}}. Some examples from the corpus:
+
+@table @code
+@item [%1:*^1:]1
+Expands to all of the values for the first argument, separated by
+@samp{*}.
+
+@item [%1 = %2:, ^1 = ^2:]1
+Given appropriate values for the first argument, expands to @code{X =
+1, Y = 2, Z = 3}.
+
+@item [%1:, ^1:]1
+Given appropriate values, expands to @code{1, 2, 3}.
+@end table
+@end table
+
+The format string is localized to the user's locale.
+@end table
+
+@example
+value-mod :=
+ 31 i0 (i0 | i1 string[subscript]) value-mod-i0-v1 /* @r{version 1} */
+ | 31 i0 (i0 | i1 string[subscript]) value-mod-i0-v3 /* @r{version 3} */
+ | 31 i1 int32[footnote-number] format
+ | 31 i2 (00 | 01 | 02) 00 (i1 | i2 | i3) format
+ | 31 i3 00 00 01 00 i2 format
+ | 58
+value-mod-i0-v1 := 00 (i1 | i2) 00 00 int32 00 00
+value-mod-i0-v3 := count(format-string
+ (58 | 31 style)
projects / pspp / blobdiff