traverseda
/
cpython
1
0
Fork 0
Code Issues Pull Requests Releases Wiki Activity

Updated markup style (got rid of \verb@...@, mostly).

This commit is contained in:
Fred Drake 1998-05-14 19:37:06 +00:00
parent 2094e044c7
commit 5c07d9b028
6 changed files with 203 additions and 197 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

24
Doc/ref/ref1.tex
View File

@ -43,20 +43,20 @@ name: lc_letter (lc_letter | "_")*
lc_letter: "a"..."z"
\end{verbatim}
The first line says that a \verb@name@ is an \verb@lc_letter@ followed by
a sequence of zero or more \verb@lc_letter@s and underscores. An
\verb@lc_letter@ in turn is any of the single characters `a' through `z'.
(This rule is actually adhered to for the names defined in lexical and
grammar rules in this document.)
The first line says that a \code{name} is an \code{lc_letter} followed by
a sequence of zero or more \code{lc_letter}s and underscores. An
\code{lc_letter} in turn is any of the single characters \character{a}
through \character{z}. (This rule is actually adhered to for the
names defined in lexical and grammar rules in this document.)
Each rule begins with a name (which is the name defined by the rule)
and a colon. A vertical bar (\verb@|@) is used to separate
and a colon. A vertical bar (\code{|}) is used to separate
alternatives; it is the least binding operator in this notation. A
star (\verb@*@) means zero or more repetitions of the preceding item;
likewise, a plus (\verb@+@) means one or more repetitions, and a
phrase enclosed in square brackets (\verb@[ ]@) means zero or one
star (\code{*}) means zero or more repetitions of the preceding item;
likewise, a plus (\code{+}) means one or more repetitions, and a
phrase enclosed in square brackets (\code{[ ]}) means zero or one
occurrences (in other words, the enclosed phrase is optional). The
\verb@*@ and \verb@+@ operators bind as tightly as possible;
\code{*} and \code{+} operators bind as tightly as possible;
parentheses are used for grouping. Literal strings are enclosed in
quotes. White space is only meaningful to separate tokens.
Rules are normally contained on a single line; rules with many
@ -66,11 +66,11 @@ first beginning with a vertical bar.
In lexical definitions (as the example above), two more conventions
are used: Two literal characters separated by three dots mean a choice
of any single character in the given (inclusive) range of \ASCII{}
characters. A phrase between angular brackets (\verb@<...>@) gives an
characters. A phrase between angular brackets (\code{<...>}) gives an
informal description of the symbol defined; e.g. this could be used
to describe the notion of `control character' if needed.
\index{lexical definitions}
\index{ASCII}
\index{ASCII@\ASCII{}}
Even though the notation used is almost the same, there is a big
difference between the meaning of lexical and syntactic definitions:

68
Doc/ref/ref2.tex
View File

@ -1,7 +1,7 @@
\chapter{Lexical analysis}
A Python program is read by a {\em parser}. Input to the parser is a
stream of {\em tokens}, generated by the {\em lexical analyzer}. This
A Python program is read by a \emph{parser}. Input to the parser is a
stream of \emph{tokens}, generated by the \emph{lexical analyzer}. This
chapter describes how the lexical analyzer breaks a file into tokens.
\index{lexical analysis}
\index{parser}
@ -19,7 +19,7 @@ syntax (e.g. between statements in compound statements).
\subsection{Comments}
A comment starts with a hash character (\verb@#@) that is not part of
A comment starts with a hash character (\code{\#}) that is not part of
a string literal, and ends at the end of the physical line. A comment
always signifies the end of the logical line. Comments are ignored by
the syntax.
@ -31,7 +31,7 @@ the syntax.
\subsection{Explicit line joining}
Two or more physical lines may be joined into logical lines using
backslash characters (\verb/\/), as follows: when a physical line ends
backslash characters (\code{\e}), as follows: when a physical line ends
in a backslash that is not part of a string literal or comment, it is
joined with the following forming a single logical line, deleting the
backslash and the following end-of-line character. For example:
@ -91,7 +91,7 @@ turn is used to determine the grouping of statements.
First, tabs are replaced (from left to right) by one to eight spaces
such that the total number of characters up to there is a multiple of
eight (this is intended to be the same rule as used by {\UNIX}). The
eight (this is intended to be the same rule as used by \UNIX{}). The
total number of spaces preceding the first non-blank character then
determines the line's indentation. Indentation cannot be split over
multiple physical lines using backslashes.
@ -107,7 +107,7 @@ the stack will always be strictly increasing from bottom to top. At
the beginning of each logical line, the line's indentation level is
compared to the top of the stack. If it is equal, nothing happens.
If it is larger, it is pushed on the stack, and one INDENT token is
generated. If it is smaller, it {\em must} be one of the numbers
generated. If it is smaller, it \emph{must} be one of the numbers
occurring on the stack; all numbers on the stack that are larger are
popped off, and for each number popped off a DEDENT token is
generated. At the end of the file, a DEDENT token is generated for
@ -145,7 +145,7 @@ The following example shows various indentation errors:
(Actually, the first three errors are detected by the parser; only the
last error is found by the lexical analyzer --- the indentation of
\verb@return r@ does not match a level popped off the stack.)
\code{return r} does not match a level popped off the stack.)
\section{Other tokens}
@ -174,10 +174,10 @@ Identifiers are unlimited in length. Case is significant.
\subsection{Keywords}
The following identifiers are used as reserved words, or {\em
keywords} of the language, and cannot be used as ordinary
identifiers. They must be spelled exactly as written here:
\index{keyword}
The following identifiers are used as reserved words, or
\emph{keywords} of the language, and cannot be used as ordinary
identifiers. They must be spelled exactly as written here:%
\index{keyword}%
\index{reserved word}
\begin{verbatim}
@ -212,13 +212,13 @@ shortstringchar: <any ASCII character except "\" or newline or the quote>
longstringchar: <any ASCII character except "\">
escapeseq: "\" <any ASCII character>
\end{verbatim}
\index{ASCII}
\index{ASCII@\ASCII{}}
In ``long strings'' (strings surrounded by sets of three quotes),
unescaped newlines and quotes are allowed (and are retained), except
that three unescaped quotes in a row terminate the string. (A
``quote'' is the character used to open the string, i.e. either
\verb/'/ or \verb/"/.)
\code{'} or \code{"}.)
Escape sequences in strings are interpreted according to rules similar
to those used by Standard C. The recognized escape sequences are:
@ -230,32 +230,32 @@ to those used by Standard C. The recognized escape sequences are:
\begin{center}
\begin{tabular}{|l|l|}
\hline
\verb/\/{\em newline} & Ignored \\
\verb/\\/ & Backslash (\verb/\/) \\
\verb/\'/ & Single quote (\verb/'/) \\
\verb/\"/ & Double quote (\verb/"/) \\
\verb/\a/ & \ASCII{} Bell (BEL) \\
\verb/\b/ & \ASCII{} Backspace (BS) \\
%\verb/\E/ & \ASCII{} Escape (ESC) \\
\verb/\f/ & \ASCII{} Formfeed (FF) \\
\verb/\n/ & \ASCII{} Linefeed (LF) \\
\verb/\r/ & \ASCII{} Carriage Return (CR) \\
\verb/\t/ & \ASCII{} Horizontal Tab (TAB) \\
\verb/\v/ & \ASCII{} Vertical Tab (VT) \\
\verb/\/{\em ooo} & \ASCII{} character with octal value {\em ooo} \\
\verb/\x/{\em xx...} & \ASCII{} character with hex value {\em xx...} \\
\code{\e}\emph{newline} & Ignored \\
\code{\e\e} & Backslash (\code{\e}) \\
\code{\e'} & Single quote (\code{'}) \\
\code{\e"} & Double quote (\code{"}) \\
\code{\e a} & \ASCII{} Bell (BEL) \\
\code{\e b} & \ASCII{} Backspace (BS) \\
%\code{\e E} & \ASCII{} Escape (ESC) \\
\code{\e f} & \ASCII{} Formfeed (FF) \\
\code{\e n} & \ASCII{} Linefeed (LF) \\
\code{\e r} & \ASCII{} Carriage Return (CR) \\
\code{\e t} & \ASCII{} Horizontal Tab (TAB) \\
\code{\e v} & \ASCII{} Vertical Tab (VT) \\
\code{\e}\emph{ooo} & \ASCII{} character with octal value \emph{ooo} \\
\code{\e x}\emph{xx...} & \ASCII{} character with hex value \emph{xx...} \\
\hline
\end{tabular}
\end{center}
\index{ASCII}
\index{ASCII@\ASCII{}}
In strict compatibility with Standard C, up to three octal digits are
In strict compatibility with Standard \C, up to three octal digits are
accepted, but an unlimited number of hex digits is taken to be part of
the hex escape (and then the lower 8 bits of the resulting hex number
are used in all current implementations...).
All unrecognized escape sequences are left in the string unchanged,
i.e., {\em the backslash is left in the string.} (This behavior is
i.e., \emph{the backslash is left in the string.} (This behavior is
useful when debugging: if an escape sequence is mistyped, the
resulting output is more easily recognized as broken. It also helps a
great deal for string literals used as regular expressions or
@ -331,8 +331,8 @@ Some examples of floating point literals:
\end{verbatim}
Note that numeric literals do not include a sign; a phrase like
\verb@-1@ is actually an expression composed of the operator
\verb@-@ and the literal \verb@1@.
\code{-1} is actually an expression composed of the operator
\code{-} and the literal \code{1}.
\section{Operators}
@ -345,7 +345,7 @@ The following tokens are operators:
< == > <= <> != >=
\end{verbatim}
The comparison operators \verb@<>@ and \verb@!=@ are alternate
The comparison operators \code{<>} and \code{!=} are alternate
spellings of the same operator.
\section{Delimiters}
@ -363,7 +363,7 @@ meaning:
The following printing \ASCII{} characters are not used in Python. Their
occurrence outside string literals and comments is an unconditional
error:
\index{ASCII}
\index{ASCII@\ASCII{}}
\begin{verbatim}
@ $ ?

4
Doc/ref/ref3.tex
View File

@ -220,14 +220,14 @@ read from a file.
\obindex{string}
\index{character}
\index{byte}
\index{ASCII}
\index{ASCII@\ASCII{}}
(On systems whose native character set is not \ASCII{}, strings may use
EBCDIC in their internal representation, provided the functions
\function{chr()} and \function{ord()} implement a mapping between \ASCII{} and
EBCDIC, and string comparison preserves the \ASCII{} order.
Or perhaps someone can propose a better rule?)
\index{ASCII}
\index{ASCII@\ASCII{}}
\index{EBCDIC}
\index{character set}
\indexii{string}{comparison}

160
Doc/ref/ref5.tex
View File

@ -2,8 +2,8 @@
\index{expression}
\index{condition}
{\bf Note:} In this and the following chapters, extended BNF notation
will be used to describe syntax, not lexical analysis.
\strong{Note:} In this and the following chapters, extended BNF
notation will be used to describe syntax, not lexical analysis.
\index{BNF}
This chapter explains the meaning of the elements of expressions and
@ -12,14 +12,14 @@ may be used wherever an expression is required by enclosing it in
parentheses. The only places where expressions are used in the syntax
instead of conditions is in expression statements and on the
right-hand side of assignment statements; this catches some nasty bugs
like accidentally writing \verb@x == 1@ instead of \verb@x = 1@.
like accidentally writing \code{x == 1} instead of \code{x = 1}.
\indexii{assignment}{statement}
The comma plays several roles in Python's syntax. It is usually an
operator with a lower precedence than all others, but occasionally
serves other purposes as well; e.g. it separates function arguments,
is used in list and dictionary constructors, and has special semantics
in \verb@print@ statements.
in \keyword{print} statements.
\index{comma}
When (one alternative of) a syntax rule has the form
@ -28,8 +28,8 @@ When (one alternative of) a syntax rule has the form
name: othername
\end{verbatim}
and no semantics are given, the semantics of this form of \verb@name@
are the same as for \verb@othername@.
and no semantics are given, the semantics of this form of \code{name}
are the same as for \code{othername}.
\index{syntax}
\section{Arithmetic conversions}
@ -38,7 +38,7 @@ are the same as for \verb@othername@.
When a description of an arithmetic operator below uses the phrase
``the numeric arguments are converted to a common type'',
this both means that if either argument is not a number, a
\verb@TypeError@ exception is raised, and that otherwise
\exception{TypeError} exception is raised, and that otherwise
the following conversions are applied:
\exindex{TypeError}
\indexii{floating point}{number}
@ -73,10 +73,10 @@ enclosure: parenth_form|list_display|dict_display|string_conversion
An identifier occurring as an atom is a reference to a local, global
or built-in name binding. If a name is assigned to anywhere in a code
block (even in unreachable code), and is not mentioned in a
\verb@global@ statement in that code block, then it refers to a local
\keyword{global} statement in that code block, then it refers to a local
name throughout that code block. When it is not assigned to anywhere
in the block, or when it is assigned to but also explicitly listed in
a \verb@global@ statement, it refers to a global name if one exists,
a \keyword{global} statement, it refers to a global name if one exists,
else to a built-in name (and this binding may dynamically change).
\indexii{name}{binding}
\index{code block}
@ -86,7 +86,7 @@ else to a built-in name (and this binding may dynamically change).
When the name is bound to an object, evaluation of the atom yields
that object. When a name is not bound, an attempt to evaluate it
raises a \verb@NameError@ exception.
raises a \exception{NameError} exception.
\exindex{NameError}
\subsection{Literals}
@ -202,10 +202,10 @@ A string conversion evaluates the contained condition list and
converts the resulting object into a string according to rules
specific to its type.
If the object is a string, a number, \verb@None@, or a tuple, list or
If the object is a string, a number, \code{None}, or a tuple, list or
dictionary containing only objects whose type is one of these, the
resulting string is a valid Python expression which can be passed to
the built-in function \verb@eval()@ to yield an expression with the
the built-in function \function{eval()} to yield an expression with the
same value (or an approximation, if floating point numbers are
involved).
@ -217,9 +217,9 @@ dictionaries that contain a reference to themselves, directly or
indirectly.)
\obindex{recursive}
The built-in function \verb@repr()@ performs exactly the same
The built-in function \function{repr()} performs exactly the same
conversion in its argument as enclosing it it reverse quotes does.
The built-in function \verb@str()@ performs a similar but more
The built-in function \function{str()} performs a similar but more
user-friendly conversion.
\bifuncindex{repr}
\bifuncindex{str}
@ -246,10 +246,11 @@ attributeref: primary "." identifier
The primary must evaluate to an object of a type that supports
attribute references, e.g. a module or a list. This object is then
asked to produce the attribute whose name is the identifier. If this
attribute is not available, the exception \verb@AttributeError@ is
raised. Otherwise, the type and value of the object produced is
determined by the object. Multiple evaluations of the same attribute
reference may yield different objects.
attribute is not available, the exception
\exception{AttributeError}\exindex{AttributeError} is raised.
Otherwise, the type and value of the object produced is determined by
the object. Multiple evaluations of the same attribute reference may
yield different objects.
\obindex{module}
\obindex{list}
@ -278,7 +279,7 @@ the value in the mapping that corresponds to that key.
If it is a sequence, the condition must evaluate to a plain integer.
If this value is negative, the length of the sequence is added to it
(so that, e.g. \verb@x[-1]@ selects the last item of \verb@x@.)
(so that, e.g. \code{x[-1]} selects the last item of \code{x}.)
The resulting value must be a nonnegative integer smaller than the
number of items in the sequence, and the subscription selects the item
whose index is that value (counting from zero).
@ -332,7 +333,7 @@ objects, and methods of class instances are callable). If it is a
class, the argument list must be empty; otherwise, the arguments are
evaluated.
A call always returns some value, possibly \verb@None@, unless it
A call always returns some value, possibly \code{None}, unless it
raises an exception. How this value is computed depends on the type
of the callable object. If it is:
@ -342,7 +343,7 @@ of the callable object. If it is:
executed, passing it the argument list. The first thing the code
block will do is bind the formal parameters to the arguments; this is
described in section \ref{function}. When the code block executes a
\verb@return@ statement, this specifies the return value of the
\keyword{return} statement, this specifies the return value of the
function call.
\indexii{function}{call}
\indexiii{user-defined}{function}{call}
@ -385,22 +386,22 @@ All unary arithmetic (and bit-wise) operations have the same priority:
u_expr: primary | "-" u_expr | "+" u_expr | "~" u_expr
\end{verbatim}
The unary \verb@"-"@ (minus) operator yields the negation of its
The unary \code{-} (minus) operator yields the negation of its
numeric argument.
\index{negation}
\index{minus}
The unary \verb@"+"@ (plus) operator yields its numeric argument
The unary \code{+} (plus) operator yields its numeric argument
unchanged.
\index{plus}
The unary \verb@"~"@ (invert) operator yields the bit-wise inversion
The unary \code{~} (invert) operator yields the bit-wise inversion
of its plain or long integer argument. The bit-wise inversion of
\verb@x@ is defined as \verb@-(x+1)@.
\code{x} is defined as \code{-(x+1)}.
\index{inversion}
In all three cases, if the argument does not have the proper type,
a \verb@TypeError@ exception is raised.
a \exception{TypeError} exception is raised.
\exindex{TypeError}
\section{Binary arithmetic operations}
@ -418,7 +419,7 @@ m_expr: u_expr | m_expr "*" u_expr
a_expr: m_expr | aexpr "+" m_expr | aexpr "-" m_expr
\end{verbatim}
The \verb@"*"@ (multiplication) operator yields the product of its
The \code{*} (multiplication) operator yields the product of its
arguments. The arguments must either both be numbers, or one argument
must be a plain integer and the other must be a sequence. In the
former case, the numbers are converted to a common type and then
@ -426,40 +427,40 @@ multiplied together. In the latter case, sequence repetition is
performed; a negative repetition factor yields an empty sequence.
\index{multiplication}
The \verb@"/"@ (division) operator yields the quotient of its
The \code{/} (division) operator yields the quotient of its
arguments. The numeric arguments are first converted to a common
type. Plain or long integer division yields an integer of the same
type; the result is that of mathematical division with the `floor'
function applied to the result. Division by zero raises the
\verb@ZeroDivisionError@ exception.
\exception{ZeroDivisionError} exception.
\exindex{ZeroDivisionError}
\index{division}
The \verb@"%"@ (modulo) operator yields the remainder from the
The \code{\%} (modulo) operator yields the remainder from the
division of the first argument by the second. The numeric arguments
are first converted to a common type. A zero right argument raises
the \verb@ZeroDivisionError@ exception. The arguments may be floating
point numbers, e.g. \verb@3.14 % 0.7@ equals \verb@0.34@. The modulo
the \exception{ZeroDivisionError} exception. The arguments may be floating
point numbers, e.g. \code{3.14 \% 0.7} equals \code{0.34}. The modulo
operator always yields a result with the same sign as its second
operand (or zero); the absolute value of the result is strictly
smaller than the second operand.
\index{modulo}
The integer division and modulo operators are connected by the
following identity: \verb@x == (x/y)*y + (x%y)@. Integer division and
modulo are also connected with the built-in function \verb@divmod()@:
\verb@divmod(x, y) == (x/y, x%y)@. These identities don't hold for
following identity: \code{x == (x/y)*y + (x\%y)}. Integer division and
modulo are also connected with the built-in function \function{divmod()}:
\code{divmod(x, y) == (x/y, x\%y)}. These identities don't hold for
floating point numbers; there a similar identity holds where
\verb@x/y@ is replaced by \verb@floor(x/y)@).
\code{x/y} is replaced by \code{floor(x/y)}).
The \verb@"+"@ (addition) operator yields the sum of its arguments.
The \code{+} (addition) operator yields the sum of its arguments.
The arguments must either both be numbers, or both sequences of the
same type. In the former case, the numbers are converted to a common
type and then added together. In the latter case, the sequences are
concatenated.
\index{addition}
The \verb@"-"@ (subtraction) operator yields the difference of its
The \code{-} (subtraction) operator yields the difference of its
arguments. The numeric arguments are first converted to a common
type.
\index{subtraction}
@ -485,7 +486,7 @@ multiplication with \code{pow(2,\var{n})}; for plain integers there is
no overflow check so this drops bits and flips the sign if the result
is not less than \code{pow(2,31)} in absolute value.
Negative shift counts raise a \verb@ValueError@ exception.
Negative shift counts raise a \exception{ValueError} exception.
\exindex{ValueError}
\section{Binary bit-wise operations}
@ -499,18 +500,18 @@ xor_expr: and_expr | xor_expr "^" and_expr
or_expr: xor_expr | or_expr "|" xor_expr
\end{verbatim}
The \verb@"&"@ operator yields the bitwise AND of its arguments, which
The \code{\&} operator yields the bitwise AND of its arguments, which
must be plain or long integers. The arguments are converted to a
common type.
\indexii{bit-wise}{and}
The \verb@"^"@ operator yields the bitwise XOR (exclusive OR) of its
The \code{\^} operator yields the bitwise XOR (exclusive OR) of its
arguments, which must be plain or long integers. The arguments are
converted to a common type.
\indexii{bit-wise}{xor}
\indexii{exclusive}{or}
The \verb@"|"@ operator yields the bitwise (inclusive) OR of its
The \code{|} operator yields the bitwise (inclusive) OR of its
arguments, which must be plain or long integers. The arguments are
converted to a common type.
\indexii{bit-wise}{or}
@ -519,19 +520,19 @@ converted to a common type.
\section{Comparisons}
\index{comparison}
Contrary to C, all comparison operations in Python have the same
Contrary to \C, all comparison operations in Python have the same
priority, which is lower than that of any arithmetic, shifting or
bitwise operation. Also contrary to C, expressions like
\verb@a < b < c@ have the interpretation that is conventional in
bitwise operation. Also contrary to \C, expressions like
\code{a < b < c} have the interpretation that is conventional in
mathematics:
\index{C}
\indexii{C}{language}
\begin{verbatim}
comparison: or_expr (comp_operator or_expr)*
comp_operator: "<"|">"|"=="|">="|"<="|"<>"|"!="|"is" ["not"]|["not"] "in"
\end{verbatim}
Comparisons yield integer values: 1 for true, 0 for false.
Comparisons yield integer values: \code{1} for true, \code{0} for false.
Comparisons can be chained arbitrarily, e.g. \code{x < y <= z} is
equivalent to \code{x < y and y <= z}, except that \code{y} is
@ -542,16 +543,16 @@ when \code{x < y} is found to be false).
Formally, if \var{a}, \var{b}, \var{c}, \ldots, \var{y}, \var{z} are
expressions and \var{opa}, \var{opb}, \ldots, \var{opy} are comparison
operators, then \var{a opa b opb c} \ldots \var{y opy z} is equivalent
to \var{a opa b} \code{and} \var{b opb c} \code{and} \ldots \code{and}
to \var{a opa b} \keyword{and} \var{b opb c} \keyword{and} \ldots \keyword{and}
\var{y opy z}, except that each expression is evaluated at most once.
Note that \var{a opa b opb c} doesn't imply any kind of comparison
between \var{a} and \var{c}, so that e.g.\ \code{x < y > z} is
perfectly legal (though perhaps not pretty).
The forms \verb@<>@ and \verb@!=@ are equivalent; for consistency with
C, \verb@!=@ is preferred; where \verb@!=@ is mentioned below
\verb@<>@ is also implied.
The forms \code{<>} and \code{!=} are equivalent; for consistency with
C, \code{!=} is preferred; where \code{!=} is mentioned below
\code{<>} is also implied.
The operators {\tt "<", ">", "==", ">=", "<="}, and {\tt "!="} compare
the values of two objects. The objects needn't have the same type.
@ -560,8 +561,8 @@ objects of different types {\em always} compare unequal, and are
ordered consistently but arbitrarily.
(This unusual definition of comparison is done to simplify the
definition of operations like sorting and the \verb@in@ and
\verb@not@ \verb@in@ operators.)
definition of operations like sorting and the \keyword{in} and
\keyword{not in} operators.)
Comparison of objects of the same type depends on the type:
@ -572,7 +573,8 @@ Numbers are compared arithmetically.
\item
Strings are compared lexicographically using the numeric equivalents
(the result of the built-in function \verb@ord@) of their characters.
(the result of the built-in function \function{ord()}) of their
characters.
\item
Tuples and lists are compared lexicographically using comparison of
@ -585,7 +587,7 @@ comparison of their sorted (key, value) lists.%
but about the only sensible definition. An earlier version of Python
compared dictionaries by identity only, but this caused surprises
because people expected to be able to test a dictionary for emptiness
by comparing it to {\tt \{\}}.}
by comparing it to \code{\{\}}.}
\item
Most other types compare unequal unless they are the same object;
@ -595,12 +597,12 @@ execution of a program.
\end{itemize}
The operators \verb@in@ and \verb@not in@ test for sequence
The operators \keyword{in} and \keyword{not in} test for sequence
membership: if \var{y} is a sequence, \code{\var{x} in \var{y}} is
true if and only if there exists an index \var{i} such that
\code{\var{x} = \var{y}[\var{i}]}.
\code{\var{x} not in \var{y}} yields the inverse truth value. The
exception \verb@TypeError@ is raised when \var{y} is not a sequence,
exception \exception{TypeError} is raised when \var{y} is not a sequence,
or when \var{y} is a string and \var{x} is not a string of length one.%
\footnote{The latter restriction is sometimes a nuisance.}
\opindex{in}
@ -608,9 +610,9 @@ or when \var{y} is a string and \var{x} is not a string of length one.%
\indexii{membership}{test}
\obindex{sequence}
The operators \verb@is@ and \verb@is not@ test for object identity:
\var{x} \code{is} \var{y} is true if and only if \var{x} and \var{y}
are the same object. \var{x} \code{is not} \var{y} yields the inverse
The operators \keyword{is} and \keyword{is not} test for object identity:
\code{\var{x} is \var{y}} is true if and only if \var{x} and \var{y}
are the same object. \code{\var{x} is not \var{y}} yields the inverse
truth value.
\opindex{is}
\opindex{is not}
@ -631,38 +633,40 @@ lambda_form: "lambda" [parameter_list]: condition
In the context of Boolean operations, and also when conditions are
used by control flow statements, the following values are interpreted
as false: \verb@None@, numeric zero of all types, empty sequences
as false: \code{None}, numeric zero of all types, empty sequences
(strings, tuples and lists), and empty mappings (dictionaries). All
other values are interpreted as true.
The operator \verb@not@ yields 1 if its argument is false, 0 otherwise.
The operator \keyword{not} yields \code{1} if its argument is false,
\code{0} otherwise.
\opindex{not}
The condition \var{x} \verb@and@ \var{y} first evaluates \var{x}; if
The condition \code{\var{x} and \var{y}} first evaluates \var{x}; if
\var{x} is false, its value is returned; otherwise, \var{y} is
evaluated and the resulting value is returned.
\opindex{and}
The condition \var{x} \verb@or@ \var{y} first evaluates \var{x}; if
The condition \code{\var{x} or \var{y}} first evaluates \var{x}; if
\var{x} is true, its value is returned; otherwise, \var{y} is
evaluated and the resulting value is returned.
\opindex{or}
(Note that \verb@and@ and \verb@or@ do not restrict the value and type
they return to 0 and 1, but rather return the last evaluated argument.
This is sometimes useful, e.g. if \verb@s@ is a string that should be
(Note that \keyword{and} and \keyword{or} do not restrict the value
and type they return to \code{0} and \code{1}, but rather return the
last evaluated argument.
This is sometimes useful, e.g.\ if \code{s} is a string that should be
replaced by a default value if it is empty, the expression
\verb@s or 'foo'@ yields the desired value. Because \verb@not@ has to
\code{s or 'foo'} yields the desired value. Because \keyword{not} has to
invent a value anyway, it does not bother to return a value of the
same type as its argument, so e.g. \verb@not 'foo'@ yields \verb@0@,
not \verb@''@.)
same type as its argument, so e.g. \code{not 'foo'} yields \code{0},
not \code{''}.)
Lambda forms (lambda expressions) have the same syntactic position as
conditions. They are a shorthand to create anonymous functions; the
expression {\em {\tt lambda} arguments{\tt :} condition}
expression \code{lambda \var{arguments}: \var{condition}}
yields a function object that behaves virtually identical to one
defined with
{\em {\tt def} name {\tt (}arguments{\tt ): return} condition}.
\code{def \var{name}(\var{arguments}): return \var{condition}}.
See section \ref{function} for the syntax of
parameter lists. Note that functions created with lambda forms cannot
contain statements.
@ -705,7 +709,7 @@ tuple, but rather yields the value of that expression (condition).
\indexii{trailing}{comma}
(To create an empty tuple, use an empty pair of parentheses:
\verb@()@.)
\code{()}.)
\section{Summary}
@ -719,14 +723,14 @@ chain from left to right --- see above).
\begin{center}
\begin{tabular}{|c|c|}
\hline
\code{or} & Boolean OR \\
\keyword{or} & Boolean OR \\
\hline
\code{and} & Boolean AND \\
\keyword{and} & Boolean AND \\
\hline
\code{not} \var{x} & Boolean NOT \\
\keyword{not} \var{x} & Boolean NOT \\
\hline
\code{in}, \code{not} \code{in} & Membership tests \\
\code{is}, \code{is} \code{not} & Identity tests \\
\keyword{in}, \keyword{not} \keyword{in} & Membership tests \\
\keyword{is}, \keyword{is not} & Identity tests \\
\code{<}, \code{<=}, \code{>}, \code{>=}, \code{<>}, \code{!=}, \code{=} &
Comparisons \\
\hline

124
Doc/ref/ref7.tex
View File

@ -6,8 +6,8 @@ or control the execution of those other statements in some way. In
general, compound statements span multiple lines, although in simple
incarnations a whole compound statement may be contained in one line.
The \verb@if@, \verb@while@ and \verb@for@ statements implement
traditional control flow constructs. \verb@try@ specifies exception
The \keyword{if}, \keyword{while} and \keyword{for} statements implement
traditional control flow constructs. \keyword{try} specifies exception
handlers and/or cleanup code for a group of statements. Function and
class definitions are also syntactically compound statements.
@ -21,7 +21,7 @@ statements on the same line as the header, following the header's
colon, or it can be one or more indented statements on subsequent
lines. Only the latter form of suite can contain nested compound
statements; the following is illegal, mostly because it wouldn't be
clear to which \verb@if@ clause a following \verb@else@ clause would
clear to which \keyword{if} clause a following \keyword{else} clause would
belong:
\index{clause}
\index{suite}
@ -32,7 +32,7 @@ if test1: if test2: print x
Also note that the semicolon binds tighter than the colon in this
context, so that in the following example, either all or none of the
\verb@print@ statements are executed:
\keyword{print} statements are executed:
\begin{verbatim}
if x < y < z: print x; print y; print z
@ -48,24 +48,24 @@ statement: stmt_list NEWLINE | compound_stmt
stmt_list: simple_stmt (";" simple_stmt)* [";"]
\end{verbatim}
Note that statements always end in a \verb@NEWLINE@ possibly followed
by a \verb@DEDENT@.
Note that statements always end in a \code{NEWLINE} possibly followed
by a \code{DEDENT}.
\index{NEWLINE token}
\index{DEDENT token}
Also note that optional continuation clauses always begin with a
keyword that cannot start a statement, thus there are no ambiguities
(the `dangling \verb@else@' problem is solved in Python by requiring
nested \verb@if@ statements to be indented).
(the `dangling \keyword{else}' problem is solved in Python by requiring
nested \keyword{if} statements to be indented).
\indexii{dangling}{else}
The formatting of the grammar rules in the following sections places
each clause on a separate line for clarity.
\section{The {\tt if} statement}
\section{The \keyword{if} statement}
\stindex{if}
The \verb@if@ statement is used for conditional execution:
The \keyword{if} statement is used for conditional execution:
\begin{verbatim}
if_stmt: "if" condition ":" suite
@ -76,17 +76,17 @@ if_stmt: "if" condition ":" suite
It selects exactly one of the suites by evaluating the conditions one
by one until one is found to be true (see section \ref{Booleans} for
the definition of true and false); then that suite is executed (and no
other part of the \verb@if@ statement is executed or evaluated). If
all conditions are false, the suite of the \verb@else@ clause, if
other part of the \keyword{if} statement is executed or evaluated). If
all conditions are false, the suite of the \keyword{else} clause, if
present, is executed.
\kwindex{elif}
\kwindex{else}
\section{The {\tt while} statement}
\section{The \keyword{while} statement}
\stindex{while}
\indexii{loop}{statement}
The \verb@while@ statement is used for repeated execution as long as a
The \keyword{while} statement is used for repeated execution as long as a
condition is true:
\begin{verbatim}
@ -96,22 +96,22 @@ while_stmt: "while" condition ":" suite
This repeatedly tests the condition and, if it is true, executes the
first suite; if the condition is false (which may be the first time it
is tested) the suite of the \verb@else@ clause, if present, is
is tested) the suite of the \keyword{else} clause, if present, is
executed and the loop terminates.
\kwindex{else}
A \verb@break@ statement executed in the first suite terminates the
loop without executing the \verb@else@ clause's suite. A
\verb@continue@ statement executed in the first suite skips the rest
A \keyword{break} statement executed in the first suite terminates the
loop without executing the \keyword{else} clause's suite. A
\keyword{continue} statement executed in the first suite skips the rest
of the suite and goes back to testing the condition.
\stindex{break}
\stindex{continue}
\section{The {\tt for} statement}
\section{The \keyword{for} statement}
\stindex{for}
\indexii{loop}{statement}
The \verb@for@ statement is used to iterate over the elements of a
The \keyword{for} statement is used to iterate over the elements of a
sequence (string, tuple or list):
\obindex{sequence}
@ -125,16 +125,16 @@ suite is then executed once for each item in the sequence, in the
order of ascending indices. Each item in turn is assigned to the
target list using the standard rules for assignments, and then the
suite is executed. When the items are exhausted (which is immediately
when the sequence is empty), the suite in the \verb@else@ clause, if
when the sequence is empty), the suite in the \keyword{else} clause, if
present, is executed, and the loop terminates.
\kwindex{in}
\kwindex{else}
\indexii{target}{list}
A \verb@break@ statement executed in the first suite terminates the
loop without executing the \verb@else@ clause's suite. A
\verb@continue@ statement executed in the first suite skips the rest
of the suite and continues with the next item, or with the \verb@else@
A \keyword{break} statement executed in the first suite terminates the
loop without executing the \keyword{else} clause's suite. A
\keyword{continue} statement executed in the first suite skips the rest
of the suite and continues with the next item, or with the \keyword{else}
clause if there was no next item.
\stindex{break}
\stindex{continue}
@ -146,14 +146,14 @@ The target list is not deleted when the loop is finished, but if the
sequence is empty, it will not have been assigned to at all by the
loop.
Hint: the built-in function \verb@range()@ returns a sequence of
Hint: the built-in function \function{range()} returns a sequence of
integers suitable to emulate the effect of Pascal's
\verb@for i := a to b do@;
e.g. \verb@range(3)@ returns the list \verb@[0, 1, 2]@.
\code{for i := a to b do};
e.g. \code{range(3)} returns the list \code{[0, 1, 2]}.
\bifuncindex{range}
\index{Pascal}
\indexii{Pascal}{language}
{\bf Warning:} There is a subtlety when the sequence is being modified
\strong{Warning:} There is a subtlety when the sequence is being modified
by the loop (this can only occur for mutable sequences, i.e. lists).
An internal counter is used to keep track of which item is used next,
and this is incremented on each iteration. When this counter has
@ -173,10 +173,10 @@ for x in a[:]:
if x < 0: a.remove(x)
\end{verbatim}
\section{The {\tt try} statement} \label{try}
\section{The \keyword{try} statement} \label{try}
\stindex{try}
The \verb@try@ statement specifies exception handlers and/or cleanup
The \keyword{try} statement specifies exception handlers and/or cleanup
code for a group of statements:
\begin{verbatim}
@ -188,13 +188,15 @@ try_fin_stmt: "try" ":" suite
"finally" ":" suite
\end{verbatim}
There are two forms of \verb@try@ statement: \verb@try...except@ and
\verb@try...finally@. These forms cannot be mixed.
There are two forms of \keyword{try} statement:
\keyword{try}...\keyword{except} and
\keyword{try}...\keyword{finally}. These forms cannot be mixed.
The \verb@try...except@ form specifies one or more exception handlers
(the \verb@except@ clauses). When no exception occurs in the
\verb@try@ clause, no exception handler is executed. When an
exception occurs in the \verb@try@ suite, a search for an exception
The \keyword{try}...\keyword{except} form specifies one or more
exception handlers
(the \keyword{except} clauses). When no exception occurs in the
\keyword{try} clause, no exception handler is executed. When an
exception occurs in the \keyword{try} suite, a search for an exception
handler is started. This inspects the except clauses in turn until
one is found that matches the exception. A condition-less except
clause, if present, must be last; it matches any exception. For an
@ -214,7 +216,7 @@ handler continues in the surrounding code and on the invocation stack.
If the evaluation of a condition in the header of an except clause
raises an exception, the original search for a handler is cancelled
and a search starts for the new exception in the surrounding code and
on the call stack (it is treated as if the entire \verb@try@ statement
on the call stack (it is treated as if the entire \keyword{try} statement
raised the exception).
When a matching except clause is found, the exception's parameter is
@ -226,10 +228,10 @@ exception, and the exception occurs in the try clause of the inner
handler, the outer handler will not handle the exception.)
Before an except clause's suite is executed, details about the
exception are assigned to three variables in the \verb@sys@ module:
\verb@sys.exc_type@ receives the object identifying the exception;
\verb@sys.exc_value@ receives the exception's parameter;
\verb@sys.exc_traceback@ receives a traceback object (see section
exception are assigned to three variables in the \module{sys} module:
\code{sys.exc_type} receives the object identifying the exception;
\code{sys.exc_value} receives the exception's parameter;
\code{sys.exc_traceback} receives a traceback object (see section
\ref{traceback}) identifying the point in the program where the
exception occurred.
\refbimodindex{sys}
@ -238,25 +240,25 @@ exception occurred.
\ttindex{exc_traceback}
\obindex{traceback}
The optional \verb@else@ clause is executed when no exception occurs
in the \verb@try@ clause. Exceptions in the \verb@else@ clause are
not handled by the preceding \verb@except@ clauses.
The optional \keyword{else} clause is executed when no exception occurs
in the \keyword{try} clause. Exceptions in the \keyword{else} clause are
not handled by the preceding \keyword{except} clauses.
\kwindex{else}
The \verb@try...finally@ form specifies a `cleanup' handler. The
\verb@try@ clause is executed. When no exception occurs, the
\verb@finally@ clause is executed. When an exception occurs in the
\verb@try@ clause, the exception is temporarily saved, the
\verb@finally@ clause is executed, and then the saved exception is
re-raised. If the \verb@finally@ clause raises another exception or
executes a \verb@return@, \verb@break@ or \verb@continue@ statement,
The \keyword{try}...\keyword{finally} form specifies a `cleanup' handler. The
\keyword{try} clause is executed. When no exception occurs, the
\keyword{finally} clause is executed. When an exception occurs in the
\keyword{try} clause, the exception is temporarily saved, the
\keyword{finally} clause is executed, and then the saved exception is
re-raised. If the \keyword{finally} clause raises another exception or
executes a \keyword{return}, \keyword{break} or \keyword{continue} statement,
the saved exception is lost.
\kwindex{finally}
When a \verb@return@ or \verb@break@ statement is executed in the
\verb@try@ suite of a \verb@try...finally@ statement, the
\verb@finally@ clause is also executed `on the way out'. A
\verb@continue@ statement is illegal in the \verb@try@ clause. (The
When a \keyword{return} or \keyword{break} statement is executed in the
\keyword{try} suite of a \keyword{try}...\keyword{finally} statement, the
\keyword{finally} clause is also executed `on the way out'. A
\keyword{continue} statement is illegal in the \keyword{try} clause. (The
reason is a problem with the current implementation --- this
restriction may be lifted in the future).
\stindex{return}
@ -295,7 +297,7 @@ as the global name space to be used when the function is called.
The function definition does not execute the function body; this gets
executed only when the function is called.
When one or more top-level parameters have the form {\em parameter =
When one or more top-level parameters have the form \var{parameter \code{=}
condition}, the function is said to have ``default parameter values''.
Default parameter values are evaluated when the function definition is
executed. For a parameter with a default value, the correponding
@ -304,7 +306,7 @@ default value is substituted. If a parameter has a default value, all
following parameters must also have a default value --- this is a
syntactic restriction that is not expressed by the grammar.%
\footnote{Currently this is not checked; instead,
{\tt def f(a=1,b)} is interpreted as {\tt def f(a=1,b=None)}.}
\code{def f(a=1, b)} is interpreted as \code{def f(a=1, b=None)}.}
\indexiii{default}{parameter}{value}
Function call semantics are described in section \ref{calls}. When a
@ -338,11 +340,11 @@ hand side's value is that of the argument.
If the formal parameter list ends in a star followed by an identifier,
preceded by zero or more comma-followed parameters, there must be at
least as many arguments as there are parameters preceding the star.
Call this number {\em N}. The first {\em N} arguments are assigned to
Call this number \var{N}. The first \var{N} arguments are assigned to
the corresponding formal parameters in the way descibed above. A
tuple containing the remaining arguments, if any, is then assigned to
the identifier following the star. This variable will always be a
tuple: if there are no extra arguments, its value is \verb@()@, if
tuple: if there are no extra arguments, its value is \code{()}, if
there is just one extra argument, it is a singleton tuple.
\indexii{variable length}{parameter list}

20
Doc/ref/ref8.tex
View File

@ -13,9 +13,9 @@ While a language specification need not prescribe how the language
interpreter is invoked, it is useful to have a notion of a complete
Python program. A complete Python program is executed in a minimally
initialized environment: all built-in and standard modules are
available, but none have been initialized, except for \verb@sys@
(various system services), \verb@__builtin__@ (built-in functions,
exceptions and \verb@None@) and \verb@__main__@. The latter is used
available, but none have been initialized, except for \module{sys}
(various system services), \module{__builtin__} (built-in functions,
exceptions and \code{None}) and \module{__main__}. The latter is used
to provide the local and global name space for execution of the
complete program.
\refbimodindex{sys}
@ -29,7 +29,7 @@ The interpreter may also be invoked in interactive mode; in this case,
it does not read and execute a complete program but reads and executes
one statement (possibly compound) at a time. The initial environment
is identical to that of a complete program; each statement is executed
in the name space of \verb@__main__@.
in the name space of \module{__main__}.
\index{interactive mode}
\refbimodindex{__main__}
@ -59,7 +59,7 @@ This syntax is used in the following situations:
\item when parsing a module;
\item when parsing a string passed to the \verb@exec@ statement;
\item when parsing a string passed to the \keyword{exec} statement;
\end{itemize}
@ -81,14 +81,14 @@ end of the input.
There are two forms of expression input. Both ignore leading
whitespace.
The string argument to \verb@eval()@ must have the following form:
The string argument to \function{eval()} must have the following form:
\bifuncindex{eval}
\begin{verbatim}
eval_input: condition_list NEWLINE*
\end{verbatim}
The input line read by \verb@input()@ must have the following form:
The input line read by \function{input()} must have the following form:
\bifuncindex{input}
\begin{verbatim}
@ -96,10 +96,10 @@ input_input: condition_list NEWLINE
\end{verbatim}
Note: to read `raw' input line without interpretation, you can use the
built-in function \verb@raw_input()@ or the \verb@readline()@ method
built-in function \function{raw_input()} or the \method{readline()} method
of file objects.
\obindex{file}
\index{input!raw}
\index{raw input}
\bifuncindex{raw_index}
\ttindex{readline}
\bifuncindex{raw_input}
\withsubitem{(file method)}{\ttindex{readline()}}