the brackets; e.g., Unicode specifies @samp{<small>} where Emacs uses
@samp{small}. }; the other elements are characters that give the
compatibility decomposition sequence of this character. For
-unassigned codepoints, the value is the character itself.
+characters that don't have decomposition sequences, and for unassigned
+codepoints, the value is a list with a single member, the character
+itself.
@item decimal-digit-value
Corresponds to the Unicode @code{Numeric_Value} property for
characters whose @code{Numeric_Type} is @samp{Decimal}. The value is
-an integer. For unassigned codepoints, the value is
-@code{nil}, which means @acronym{NaN}, or ``not-a-number''.
+an integer, or @code{nil} if the character has no decimal digit value.
+For unassigned codepoints, the value is @code{nil}, which means
+@acronym{NaN}, or not a number.
@item digit-value
Corresponds to the Unicode @code{Numeric_Value} property for
characters whose @code{Numeric_Type} is @samp{Digit}. The value is an
-integer. Examples of such characters include compatibility
-subscript and superscript digits, for which the value is the
-corresponding number. For unassigned codepoints, the value is
-@code{nil}, which means @acronym{NaN}.
+integer. Examples of such characters include compatibility subscript
+and superscript digits, for which the value is the corresponding
+number. For characters that don't have any numeric value, and for
+unassigned codepoints, the value is @code{nil}, which means
+@acronym{NaN}.
@item numeric-value
Corresponds to the Unicode @code{Numeric_Value} property for
characters whose @code{Numeric_Type} is @samp{Numeric}. The value of
-this property is a number. Examples of
-characters that have this property include fractions, subscripts,
-superscripts, Roman numerals, currency numerators, and encircled
-numbers. For example, the value of this property for the character
-@code{U+2155} (@sc{vulgar fraction one fifth}) is @code{0.2}. For
-unassigned codepoints, the value is @code{nil}, which means
-@acronym{NaN}.
+this property is a number. Examples of characters that have this
+property include fractions, subscripts, superscripts, Roman numerals,
+currency numerators, and encircled numbers. For example, the value of
+this property for the character @code{U+2155} (@sc{vulgar fraction one
+fifth}) is @code{0.2}. For characters that don't have any numeric
+value, and for unassigned codepoints, the value is @code{nil}, which
+means @acronym{NaN}.
@cindex mirroring of characters
@item mirrored
@item iso-10646-comment
Corresponds to the Unicode @code{ISO_Comment} property. The value is
-a string. For unassigned codepoints, the value is an empty string.
+either a string or @code{nil}. For unassigned codepoints, the value
+is @code{nil}.
@item uppercase
Corresponds to the Unicode @code{Simple_Uppercase_Mapping} property.
@section Locales
@cindex locale
- POSIX defines a concept of ``locales'' which control which language
+ In POSIX, locales control which language
to use in language-related features. These Emacs variables control
how Emacs interacts with these features.
@cindex keyboard input decoding on X
This variable specifies the coding system to use for decoding system
error messages and---on X Window system only---keyboard input, for
+sending batch output to the standard output and error streams, for
encoding the format argument to @code{format-time-string}, and for
decoding the return value of @code{format-time-string}.
@end defvar