diff options
Diffstat (limited to 'Doc/ref/ref2.tex')
-rw-r--r-- | Doc/ref/ref2.tex | 106 |
1 files changed, 68 insertions, 38 deletions
diff --git a/Doc/ref/ref2.tex b/Doc/ref/ref2.tex index c08f7f4..8a44b03 100644 --- a/Doc/ref/ref2.tex +++ b/Doc/ref/ref2.tex @@ -237,13 +237,18 @@ lexical definitions: \index{identifier} \index{name} -\begin{verbatim} -identifier: (letter|"_") (letter|digit|"_")* -letter: lowercase | uppercase -lowercase: "a"..."z" -uppercase: "A"..."Z" -digit: "0"..."9" -\end{verbatim} +\begin{productionlist} + \production{identifier} + {(\token{letter}|"_") (\token{letter} | \token{digit} | "_")*} + \production{letter} + {\token{lowercase} | \token{uppercase}} + \production{lowercase} + {"a"..."z"} + \production{uppercase} + {"A"..."Z"} + \production{digit} + {"0"..."9"} +\end{productionlist} Identifiers are unlimited in length. Case is significant. @@ -303,17 +308,27 @@ Literals are notations for constant values of some built-in types. String literals are described by the following lexical definitions: \index{string literal} -\begin{verbatim} -stringliteral: shortstring | longstring -shortstring: "'" shortstringitem* "'" | '"' shortstringitem* '"' -longstring: "'''" longstringitem* "'''" | '"""' longstringitem* '"""' -shortstringitem: shortstringchar | escapeseq -longstringitem: longstringchar | escapeseq -shortstringchar: <any ASCII character except "\" or newline or the quote> -longstringchar: <any ASCII character except "\"> -escapeseq: "\" <any ASCII character> -\end{verbatim} \index{ASCII@\ASCII{}} +\begin{productionlist} + \production{stringliteral} + {\token{shortstring} | \token{longstring}} + \production{shortstring} + {"'" \token{shortstringitem}* "'" + | '"' \token{shortstringitem}* '"'} + \production{longstring} + {"'''" \token{longstringitem}* "'''" + | '"""' \token{longstringitem}* '"""'} + \production{shortstringitem} + {\token{shortstringchar} | \token{escapeseq}} + \production{longstringitem} + {\token{longstringchar} | \token{escapeseq}} + \production{shortstringchar} + {<any ASCII character except "\e" or newline or the quote>} + \production{longstringchar} + {<any ASCII character except "\e">} + \production{escapeseq} + {"\e" <any ASCII character>} +\end{productionlist} \index{triple-quoted string} \index{Unicode Consortium} @@ -452,16 +467,24 @@ Note that numeric literals do not include a sign; a phrase like Integer and long integer literals are described by the following lexical definitions: -\begin{verbatim} -longinteger: integer ("l"|"L") -integer: decimalinteger | octinteger | hexinteger -decimalinteger: nonzerodigit digit* | "0" -octinteger: "0" octdigit+ -hexinteger: "0" ("x"|"X") hexdigit+ -nonzerodigit: "1"..."9" -octdigit: "0"..."7" -hexdigit: digit|"a"..."f"|"A"..."F" -\end{verbatim} +\begin{productionlist} + \production{longinteger} + {\token{integer} ("l" | "L")} + \production{integer} + {\token{decimalinteger} | \token{octinteger} | \token{hexinteger}} + \production{decimalinteger} + {\token{nonzerodigit} \token{digit}* | "0"} + \production{octinteger} + {"0" \token{octdigit}+} + \production{hexinteger} + {"0" ("x" | "X") \token{hexdigit}+} + \production{nonzerodigit} + {"1"..."9"} + \production{octdigit} + {"0"..."7"} + \production{hexdigit} + {\token{digit} | "a"..."f" | "A"..."F"} +\end{productionlist} Although both lower case `l' and upper case `L' are allowed as suffix for long integers, it is strongly recommended to always use `L', since @@ -487,14 +510,21 @@ Some examples of plain and long integer literals: Floating point literals are described by the following lexical definitions: -\begin{verbatim} -floatnumber: pointfloat | exponentfloat -pointfloat: [intpart] fraction | intpart "." -exponentfloat: (nonzerodigit digit* | pointfloat) exponent -intpart: nonzerodigit digit* | "0" -fraction: "." digit+ -exponent: ("e"|"E") ["+"|"-"] digit+ -\end{verbatim} +\begin{productionlist} + \production{floatnumber} + {\token{pointfloat} | \token{exponentfloat}} + \production{pointfloat} + {[\token{intpart}] \token{fraction} | \token{intpart} "."} + \production{exponentfloat} + {(\token{nonzerodigit} \token{digit}* | \token{pointfloat}) + \token{exponent}} + \production{intpart} + {\token{nonzerodigit} \token{digit}* | "0"} + \production{fraction} + {"." \token{digit}+} + \production{exponent} + {("e" | "E") ["+" | "-"] \token{digit}+} +\end{productionlist} Note that the integer part of a floating point number cannot look like an octal integer, though the exponent may look like an octal literal @@ -517,9 +547,9 @@ Note that numeric literals do not include a sign; a phrase like Imaginary literals are described by the following lexical definitions: -\begin{verbatim} -imagnumber: (floatnumber | intpart) ("j"|"J") -\end{verbatim} +\begin{productionlist} + \production{imagnumber}{(\token{floatnumber} | \token{intpart}) ("j" | "J")} +\end{productionlist} An imaginary literal yields a complex number with a real part of 0.0. Complex numbers are represented as a pair of floating point |