Update of /cvsroot/python/python/dist/src/Doc/ref
In directory usw-pr-cvs1:/tmp/cvs-serv30079
Modified Files:
Tag: release22-maint
ref6.tex
Log Message:
Backport 1.54 1.53 1.52 1.51 1.50 and 1.49:
Try to improve the explanation of the "raise" statement and how its arguments
are interpreted.
This closes SF bug #532467.
Fix Typo.
Reword explanation of global statement since an undeclared global is a
free variable and is subject to those rules.
Note the sole case in which the ban on "from ... import *" within a
function is enforced.
Remove the following restriction:
Names bound by import statements may not occur in global
statements in the same scope.
Why not?
Note that it is illegal to delete a cell variable.
Note that deleteing an unbound local will raise a NameError.
Index: ref6.tex
===================================================================
RCS file: /cvsroot/python/python/dist/src/Doc/ref/ref6.tex,v
retrieving revision 1.47.4.2
retrieving revision 1.47.4.3
diff -C2 -d -r1.47.4.2 -r1.47.4.3
*** ref6.tex 25 Jun 2002 13:39:49 -0000 1.47.4.2
--- ref6.tex 5 Oct 2002 06:12:08 -0000 1.47.4.3
***************
*** 353,362 ****
to right.
! Deletion of a name removes the binding of that name (which must exist)
from the local or global namespace, depending on whether the name
! occurs in a \keyword{global} statement in the same code block.
\stindex{global}
\indexii{unbinding}{name}
Deletion of attribute references, subscriptions and slicings
is passed to the primary object involved; deletion of a slicing
--- 353,366 ----
to right.
! Deletion of a name removes the binding of that name
from the local or global namespace, depending on whether the name
! occurs in a \keyword{global} statement in the same code block. If the
! name is unbound, a \exception{NameError} exception will be raised.
\stindex{global}
\indexii{unbinding}{name}
+ It is illegal to delete a name from the local namespace if it occurs
+ as a free variable\indexii{free}{variable} in a nested block.
+
Deletion of attribute references, subscriptions and slicings
is passed to the primary object involved; deletion of a slicing
***************
*** 518,552 ****
If no expressions are present, \keyword{raise} re-raises the last
! expression that was raised in the current scope.
!
! Otherwise, \keyword{raise} evaluates its first expression, which must yield
! a string, class, or instance object. If there is a second expression,
! this is evaluated, else \code{None} is substituted. If the first
! expression is a class object, then the second expression may be an
! instance of that class or one of its derivatives, and then that
! instance is raised. If the second expression is not such an instance,
! the given class is instantiated. The argument list for the
! instantiation is determined as follows: if the second expression is a
! tuple, it is used as the argument list; if it is \code{None}, the
! argument list is empty; otherwise, the argument list consists of a
! single argument which is the second expression. If the first
! expression is an instance object, the second expression must be
! \code{None}.
\index{exception}
\indexii{raising}{exception}
! If the first object is a string, it then raises the exception
! identified by the first object, with the second one (or \code{None})
! as its parameter. If the first object is a class or instance,
! it raises the exception identified by the class of the instance
! determined in the previous step, with the instance as
! its parameter.
- If a third object is present, and it is not \code{None}, it should be
- a traceback object (see section~\ref{traceback}), and it is
- substituted instead of the current location as the place where the
- exception occurred. This is useful to re-raise an exception
- transparently in an except clause.
- \obindex{traceback}
--- 522,563 ----
If no expressions are present, \keyword{raise} re-raises the last
! expression that was active in the current scope. If no exception has
! been active in the current scope, an exception is raised that
! indicates indicates that this is the error.
\index{exception}
\indexii{raising}{exception}
! Otherwise, \keyword{raise} evaluates the expressions to get three
! objects, using \code{None} as the value of omitted expressions. The
! first two objects are used to determine the \emph{type} and
! \emph{value} of the exception.
!
! If the first object is an instance, the type of the exception is the
! class of the instance, the instance itself if the value, and the
! second object must be \code{None}.
!
! If the first object is a class, it becomes the type of the exception.
! The second object is used to determine the exception value: If it is
! an instance of the class, the instance becomes the exception value.
! If the second object is a tuple, it is used as the argument list for
! the class constructor; if it is \code{None}, an empty argument list is
! used, and any other object is treated as a single argument to the
! constructor. The instance so created by calling the constructor is
! used as the exception value.
!
! If the first object is a string, the string object is the exception
! type, and the second object becomes the exception value.
!
! If a third object is present and not \code{None}, it must be a
! traceback\obindex{traceback} object (see section~\ref{traceback}), and
! it is substituted instead of the current location as the place where
! the exception occurred. If the third object is present and not a
! traceback object or \code{None}, a \exception{TypeError} exception is
! raised. The three-expression form of \keyword{raise} is useful to
! re-raise an exception transparently in an except clause, but
! \keyword{raise} with no expressions should be preferred if the
! exception to be re-raised was the most recently active exception in
! the current scope.
***************
*** 691,699 ****
(\character{_}).
! Names bound by \keyword{import} statements may not occur in
! \keyword{global} statements in the same scope.
! \stindex{global}
- The \keyword{from} form with \samp{*} may only occur in a module scope.
\kwindex{from}
\stindex{from}
--- 702,710 ----
(\character{_}).
! The \keyword{from} form with \samp{*} may only occur in a module
! scope. If the wild card form of import --- \samp{import *} --- is
! used in a function and the function contains or is a nested block with
! free variables, the compiler will raise a \exception{SyntaxError}.
\kwindex{from}
\stindex{from}
***************
*** 730,736 ****
The \keyword{global} statement is a declaration which holds for the
entire current code block. It means that the listed identifiers are to be
! interpreted as globals. While \emph{using} global names is automatic
! if they are not defined in the local scope, \emph{assigning} to global
! names would be impossible without \keyword{global}.
\indexiii{global}{name}{binding}
--- 741,747 ----
The \keyword{global} statement is a declaration which holds for the
entire current code block. It means that the listed identifiers are to be
! interpreted as globals. It would be impossible to assign to a global
! variable without \keyword{global}, although free variables may refer
! to globals without being declared global.
\indexiii{global}{name}{binding}
In directory usw-pr-cvs1:/tmp/cvs-serv30079
Modified Files:
Tag: release22-maint
ref6.tex
Log Message:
Backport 1.54 1.53 1.52 1.51 1.50 and 1.49:
Try to improve the explanation of the "raise" statement and how its arguments
are interpreted.
This closes SF bug #532467.
Fix Typo.
Reword explanation of global statement since an undeclared global is a
free variable and is subject to those rules.
Note the sole case in which the ban on "from ... import *" within a
function is enforced.
Remove the following restriction:
Names bound by import statements may not occur in global
statements in the same scope.
Why not?
Note that it is illegal to delete a cell variable.
Note that deleteing an unbound local will raise a NameError.
Index: ref6.tex
===================================================================
RCS file: /cvsroot/python/python/dist/src/Doc/ref/ref6.tex,v
retrieving revision 1.47.4.2
retrieving revision 1.47.4.3
diff -C2 -d -r1.47.4.2 -r1.47.4.3
*** ref6.tex 25 Jun 2002 13:39:49 -0000 1.47.4.2
--- ref6.tex 5 Oct 2002 06:12:08 -0000 1.47.4.3
***************
*** 353,362 ****
to right.
! Deletion of a name removes the binding of that name (which must exist)
from the local or global namespace, depending on whether the name
! occurs in a \keyword{global} statement in the same code block.
\stindex{global}
\indexii{unbinding}{name}
Deletion of attribute references, subscriptions and slicings
is passed to the primary object involved; deletion of a slicing
--- 353,366 ----
to right.
! Deletion of a name removes the binding of that name
from the local or global namespace, depending on whether the name
! occurs in a \keyword{global} statement in the same code block. If the
! name is unbound, a \exception{NameError} exception will be raised.
\stindex{global}
\indexii{unbinding}{name}
+ It is illegal to delete a name from the local namespace if it occurs
+ as a free variable\indexii{free}{variable} in a nested block.
+
Deletion of attribute references, subscriptions and slicings
is passed to the primary object involved; deletion of a slicing
***************
*** 518,552 ****
If no expressions are present, \keyword{raise} re-raises the last
! expression that was raised in the current scope.
!
! Otherwise, \keyword{raise} evaluates its first expression, which must yield
! a string, class, or instance object. If there is a second expression,
! this is evaluated, else \code{None} is substituted. If the first
! expression is a class object, then the second expression may be an
! instance of that class or one of its derivatives, and then that
! instance is raised. If the second expression is not such an instance,
! the given class is instantiated. The argument list for the
! instantiation is determined as follows: if the second expression is a
! tuple, it is used as the argument list; if it is \code{None}, the
! argument list is empty; otherwise, the argument list consists of a
! single argument which is the second expression. If the first
! expression is an instance object, the second expression must be
! \code{None}.
\index{exception}
\indexii{raising}{exception}
! If the first object is a string, it then raises the exception
! identified by the first object, with the second one (or \code{None})
! as its parameter. If the first object is a class or instance,
! it raises the exception identified by the class of the instance
! determined in the previous step, with the instance as
! its parameter.
- If a third object is present, and it is not \code{None}, it should be
- a traceback object (see section~\ref{traceback}), and it is
- substituted instead of the current location as the place where the
- exception occurred. This is useful to re-raise an exception
- transparently in an except clause.
- \obindex{traceback}
--- 522,563 ----
If no expressions are present, \keyword{raise} re-raises the last
! expression that was active in the current scope. If no exception has
! been active in the current scope, an exception is raised that
! indicates indicates that this is the error.
\index{exception}
\indexii{raising}{exception}
! Otherwise, \keyword{raise} evaluates the expressions to get three
! objects, using \code{None} as the value of omitted expressions. The
! first two objects are used to determine the \emph{type} and
! \emph{value} of the exception.
!
! If the first object is an instance, the type of the exception is the
! class of the instance, the instance itself if the value, and the
! second object must be \code{None}.
!
! If the first object is a class, it becomes the type of the exception.
! The second object is used to determine the exception value: If it is
! an instance of the class, the instance becomes the exception value.
! If the second object is a tuple, it is used as the argument list for
! the class constructor; if it is \code{None}, an empty argument list is
! used, and any other object is treated as a single argument to the
! constructor. The instance so created by calling the constructor is
! used as the exception value.
!
! If the first object is a string, the string object is the exception
! type, and the second object becomes the exception value.
!
! If a third object is present and not \code{None}, it must be a
! traceback\obindex{traceback} object (see section~\ref{traceback}), and
! it is substituted instead of the current location as the place where
! the exception occurred. If the third object is present and not a
! traceback object or \code{None}, a \exception{TypeError} exception is
! raised. The three-expression form of \keyword{raise} is useful to
! re-raise an exception transparently in an except clause, but
! \keyword{raise} with no expressions should be preferred if the
! exception to be re-raised was the most recently active exception in
! the current scope.
***************
*** 691,699 ****
(\character{_}).
! Names bound by \keyword{import} statements may not occur in
! \keyword{global} statements in the same scope.
! \stindex{global}
- The \keyword{from} form with \samp{*} may only occur in a module scope.
\kwindex{from}
\stindex{from}
--- 702,710 ----
(\character{_}).
! The \keyword{from} form with \samp{*} may only occur in a module
! scope. If the wild card form of import --- \samp{import *} --- is
! used in a function and the function contains or is a nested block with
! free variables, the compiler will raise a \exception{SyntaxError}.
\kwindex{from}
\stindex{from}
***************
*** 730,736 ****
The \keyword{global} statement is a declaration which holds for the
entire current code block. It means that the listed identifiers are to be
! interpreted as globals. While \emph{using} global names is automatic
! if they are not defined in the local scope, \emph{assigning} to global
! names would be impossible without \keyword{global}.
\indexiii{global}{name}{binding}
--- 741,747 ----
The \keyword{global} statement is a declaration which holds for the
entire current code block. It means that the listed identifiers are to be
! interpreted as globals. It would be impossible to assign to a global
! variable without \keyword{global}, although free variables may refer
! to globals without being declared global.
\indexiii{global}{name}{binding}