Remove backspace and bel escape sequences

doc/appendix.tex

@@ -21,7 +21,7 @@
 
 <printable-character> = \enspace? a printable ASCII character\space?.
 
-<character> = <printable-character> | <escaped-character> | <hex-digit>.
+<character> = <printable-character> | <escaped-character> | <hex-character>.
 
 <identifier> = <letter> \{<letter> | <decimal-digit>\}.
 
@@ -38,10 +38,10 @@
 <real-literal> = <integer-literal> `.\@' <decimal-digit> \{<decimal-digit>\}
 	\alt{} <integer-literal>\} `e' [`+' | `-'] <decimal-digit> \{<decimal-digit>\}.
 
-<string-literal> = `\textquotedbl' \{<character>\} `\textquotedbl'.
-
 <character-literal> = `\textquotesingle' <character> `\textquotesingle'.
 
+<string-literal> = `\textquotedbl' \{<character>\} `\textquotedbl'.
+
 <literal> = <integer-literal> | <word-literal> | <real-literal>
 	\alt{} <string-literal> | <character-literal>
 	\alt{} `true' | `false' | `nil'.

doc/language.tex

@@ -77,6 +77,25 @@ Examples:
 
 \section{Strings and characters}
 
+Single \textit{characters} are enclosed in single quotation marks
+(\textquotesingle).\@ \textit{Strings} are sequences of characters enclosed in
+double quotation marks (\textquotedbl). The number of characters in a string is
+called the \textit{the length} of the string.
+
+\begin{grammar}
+<hex-character> = `\\x' <hex-digit> <hex-digit>.
+
+<character> = <printable-character> | <escaped-character> | <hex-character>.
+
+<character-literal> = `\textquotesingle' <character> `\textquotesingle'.
+
+<string-literal> = `\textquotedbl' \{<character>\} `\textquotedbl'.
+\end{grammar}
+
+Alternatively, a single character may be represented by a
+\textit{escape sequence}, a character combination beginning with a
+backslash (\textbackslash).
+
 \section{Operators and delimiters}
 
 \section{Comments}