* Doc/libtime.tex: get rid of references to millitime() and

	millisleep(); document clock()

	* Doc/ref6.tex (section{Assignment statements}): added warning
	about overlaps in lhs of assignment (e.g. "i, x[i] = 1, 2")

Doc/lib/libtime.tex

@@ -2,8 +2,7 @@
 
 \bimodindex{time}
 This module provides various time-related functions.
-It is always available.  (On some systems, not all functions may
-exist; e.g. the ``milli'' variants can't always be implemented.)
+It is always available.
 
 An explanation of some terminology and conventions is in order.
 
@@ -55,6 +54,13 @@ the same name, there is no trailing newline.
 \end{funcdesc}
 
 
+\begin{funcdesc}{clock}{}
+Return the current CPU time as a floating point number expressed in
+seconds.  The precision depends on that of the C function by the same
+name.
+\end{funcdesc}
+
+
 \begin{funcdesc}{ctime}{secs}
 Convert a time expressed in seconds since the epoch to a string
 representing local time.  \code{ctime(t)} is equivalent to
@@ -78,18 +84,6 @@ Like \code{gmtime} but converts to local time.  The dst flag is set
 to 1 when DST applies to the given time.
 \end{funcdesc}
 
-\begin{funcdesc}{millisleep}{msecs}
-Suspend execution for the given number of milliseconds.  (Obsolete,
-you can now use use \code{sleep} with a floating point argument.)
-\end{funcdesc}
-
-\begin{funcdesc}{millitimer}{}
-Return the number of milliseconds of real time elapsed since some
-point in the past that is fixed per execution of the python
-interpreter (but may change in each following run).  The return value
-may be negative, and it may wrap around.
-\end{funcdesc}
-
 \begin{funcdesc}{mktime}{tuple}
 This is the inverse function of \code{localtime}.  Its argument is the
 full 9-tuple (since the dst flag is needed).  It returns an integer.
@@ -104,8 +98,7 @@ be a floating point number to indicate a more precise sleep time.
 Return the time as a floating point number expressed in seconds since
 the epoch, in UTC.  Note that even though the time is always returned
 as a floating point number, not all systems provide time with a better
-precision than 1 second.  An alternative for measuring precise
-intervals is \code{millitimer}.
+precision than 1 second.
 \end{funcdesc}
 
 \begin{datadesc}{timezone}

Doc/libtime.tex

@@ -2,8 +2,7 @@
 
 \bimodindex{time}
 This module provides various time-related functions.
-It is always available.  (On some systems, not all functions may
-exist; e.g. the ``milli'' variants can't always be implemented.)
+It is always available.
 
 An explanation of some terminology and conventions is in order.
 
@@ -55,6 +54,13 @@ the same name, there is no trailing newline.
 \end{funcdesc}
 
 
+\begin{funcdesc}{clock}{}
+Return the current CPU time as a floating point number expressed in
+seconds.  The precision depends on that of the C function by the same
+name.
+\end{funcdesc}
+
+
 \begin{funcdesc}{ctime}{secs}
 Convert a time expressed in seconds since the epoch to a string
 representing local time.  \code{ctime(t)} is equivalent to
@@ -78,18 +84,6 @@ Like \code{gmtime} but converts to local time.  The dst flag is set
 to 1 when DST applies to the given time.
 \end{funcdesc}
 
-\begin{funcdesc}{millisleep}{msecs}
-Suspend execution for the given number of milliseconds.  (Obsolete,
-you can now use use \code{sleep} with a floating point argument.)
-\end{funcdesc}
-
-\begin{funcdesc}{millitimer}{}
-Return the number of milliseconds of real time elapsed since some
-point in the past that is fixed per execution of the python
-interpreter (but may change in each following run).  The return value
-may be negative, and it may wrap around.
-\end{funcdesc}
-
 \begin{funcdesc}{mktime}{tuple}
 This is the inverse function of \code{localtime}.  Its argument is the
 full 9-tuple (since the dst flag is needed).  It returns an integer.
@@ -104,8 +98,7 @@ be a floating point number to indicate a more precise sleep time.
 Return the time as a floating point number expressed in seconds since
 the epoch, in UTC.  Note that even though the time is always returned
 as a floating point number, not all systems provide time with a better
-precision than 1 second.  An alternative for measuring precise
-intervals is \code{millitimer}.
+precision than 1 second.
 \end{funcdesc}
 
 \begin{datadesc}{timezone}

Doc/ref/ref6.tex

@@ -190,11 +190,25 @@ target sequence, if the object allows it.
 
 \end{itemize}
 	
-(In the original implementation, the syntax for targets is taken
+(In the current implementation, the syntax for targets is taken
 to be the same as for expressions, and invalid syntax is rejected
 during the code generation phase, causing less detailed error
 messages.)
 
+WARNING: Although the definition of assignment implies that overlaps
+between the left-hand side and the right-hand side are `safe' (e.g.
+\verb@a, b = b, a@ swaps two variables), overlaps within the
+collection of assigned-to variables are not safe!  For instance, the
+following program prints \code@[0, 2]@:
+
+\begin{verbatim}
+x = [0, 1]
+i = 0
+i, x[i] = 1, 2
+print x
+\end{verbatim}
+
+
 \section{The {\tt pass} statement}
 \stindex{pass}
 

Doc/ref6.tex

@@ -190,11 +190,25 @@ target sequence, if the object allows it.
 
 \end{itemize}
 	
-(In the original implementation, the syntax for targets is taken
+(In the current implementation, the syntax for targets is taken
 to be the same as for expressions, and invalid syntax is rejected
 during the code generation phase, causing less detailed error
 messages.)
 
+WARNING: Although the definition of assignment implies that overlaps
+between the left-hand side and the right-hand side are `safe' (e.g.
+\verb@a, b = b, a@ swaps two variables), overlaps within the
+collection of assigned-to variables are not safe!  For instance, the
+following program prints \code@[0, 2]@:
+
+\begin{verbatim}
+x = [0, 1]
+i = 0
+i, x[i] = 1, 2
+print x
+\end{verbatim}
+
+
 \section{The {\tt pass} statement}
 \stindex{pass}