Relocating file to Doc/ref.

1 files changed, 0 insertions, 391 deletions

diff --git a/Doc/ref7.tex b/Doc/ref7.tex
deleted file mode 100644
index f5b8a0e..0000000
--- a/Doc/ref7.tex
+++ /dev/null
@@ -1,391 +0,0 @@
-\chapter{Compound statements}
-\indexii{compound}{statement}
-
-Compound statements contain (groups of) other statements; they affect
-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
-handlers and/or cleanup code for a group of statements.  Function and
-class definitions are also syntactically compound statements.
-
-Compound statements consist of one or more `clauses'.  A clause
-consists of a header and a `suite'.  The clause headers of a
-particular compound statement are all at the same indentation level.
-Each clause header begins with a uniquely identifying keyword and ends
-with a colon.  A suite is a group of statements controlled by a
-clause.  A suite can be one or more semicolon-separated simple
-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
-belong:
-\index{clause}
-\index{suite}
-
-\begin{verbatim}
-if test1: if test2: print x
-\end{verbatim}
-
-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:
-
-\begin{verbatim}
-if x < y < z: print x; print y; print z
-\end{verbatim}
-
-Summarizing:
-
-\begin{verbatim}
-compound_stmt:  if_stmt | while_stmt | for_stmt
-              | try_stmt | funcdef | classdef
-suite:          stmt_list NEWLINE | NEWLINE INDENT statement+ DEDENT
-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@.
-\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).
-\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}
-\stindex{if}
-
-The \verb@if@ statement is used for conditional execution:
-
-\begin{verbatim}
-if_stmt:        "if" condition ":" suite
-               ("elif" condition ":" suite)*
-               ["else" ":" suite]
-\end{verbatim}
-
-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
-present, is executed.
-\kwindex{elif}
-\kwindex{else}
-
-\section{The {\tt while} statement}
-\stindex{while}
-\indexii{loop}{statement}
-
-The \verb@while@ statement is used for repeated execution as long as a
-condition is true:
-
-\begin{verbatim}
-while_stmt:     "while" condition ":" suite
-               ["else" ":" suite]
-\end{verbatim}
-
-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
-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
-of the suite and goes back to testing the condition.
-\stindex{break}
-\stindex{continue}
-
-\section{The {\tt for} statement}
-\stindex{for}
-\indexii{loop}{statement}
-
-The \verb@for@ statement is used to iterate over the elements of a
-sequence (string, tuple or list):
-\obindex{sequence}
-
-\begin{verbatim}
-for_stmt:       "for" target_list "in" condition_list ":" suite
-               ["else" ":" suite]
-\end{verbatim}
-
-The condition list is evaluated once; it should yield a sequence.  The
-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
-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@
-clause if there was no next item.
-\stindex{break}
-\stindex{continue}
-
-The suite may assign to the variable(s) in the target list; this does
-not affect the next item assigned to it.
-
-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
-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]@.
-\bifuncindex{range}
-\index{Pascal}
-
-{\bf 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
-reached the length of the sequence the loop terminates.  This means that
-if the suite deletes the current (or a previous) item from the
-sequence, the next item will be skipped (since it gets the index of
-the current item which has already been treated).  Likewise, if the
-suite inserts an item in the sequence before the current item, the
-current item will be treated again the next time through the loop.
-This can lead to nasty bugs that can be avoided by making a temporary
-copy using a slice of the whole sequence, e.g.
-\index{loop!over mutable sequence}
-\index{mutable sequence!loop over}
-
-\begin{verbatim}
-for x in a[:]:
-    if x < 0: a.remove(x)
-\end{verbatim}
-
-\section{The {\tt try} statement} \label{try}
-\stindex{try}
-
-The \verb@try@ statement specifies exception handlers and/or cleanup
-code for a group of statements:
-
-\begin{verbatim}
-try_stmt:       try_exc_stmt | try_fin_stmt
-try_exc_stmt:   "try" ":" suite
-               ("except" [condition ["," target]] ":" suite)+
-               ["else" ":" suite]
-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.
-
-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
-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
-except clause with a condition, that condition is evaluated, and the
-clause matches the exception if the resulting object is ``compatible''
-with the exception.  An object is compatible with an exception if it
-is either the object that identifies the exception, or (for exceptions
-that are classes) it is a base class of the exception, or it is a
-tuple containing an item that is compatible with the exception.  Note
-that the object identities must match, i.e. it must be the same
-object, not just an object with the same value.
-\kwindex{except}
-
-If no except clause matches the exception, the search for an exception
-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
-raised the exception).
-
-When a matching except clause is found, the exception's parameter is
-assigned to the target specified in that except clause, if present,
-and the except clause's suite is executed.  When the end of this suite
-is reached, execution continues normally after the entire try
-statement.  (This means that if two nested handlers exist for the same
-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
-\ref{traceback}) identifying the point in the program where the
-exception occurred.
-\refbimodindex{sys}
-\ttindex{exc_type}
-\ttindex{exc_value}
-\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.
-\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 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
-reason is a problem with the current implementation --- this
-restriction may be lifted in the future).
-\stindex{return}
-\stindex{break}
-\stindex{continue}
-
-\section{Function definitions} \label{function}
-\indexii{function}{definition}
-
-A function definition defines a user-defined function object (see
-section \ref{types}):\footnote{The new syntax to receive arbitrary
-keyword arguments is not yet documented in this manual.  See chapter
-12 of the Tutorial.}
-\obindex{user-defined function}
-\obindex{function}
-
-\begin{verbatim}
-funcdef:        "def" funcname "(" [parameter_list] ")" ":" suite
-parameter_list: (defparameter ",")* ("*" identifier [, "**" identifier] 
-                                    | "**" identifier 
-                                    | defparameter [","])
-defparameter:   parameter ["=" condition]
-sublist:        parameter ("," parameter)* [","]
-parameter:      identifier | "(" sublist ")"
-funcname:       identifier
-\end{verbatim}
-
-A function definition is an executable statement.  Its execution binds
-the function name in the current local name space to a function object
-(a wrapper around the executable code for the function).  This
-function object contains a reference to the current global name space
-as the global name space to be used when the function is called.
-\indexii{function}{name}
-\indexii{name}{binding}
-
-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 =
-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
-argument may be omitted from a call, in which case the parameter's
-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)}.}
-\indexiii{default}{parameter}{value}
-
-Function call semantics are described in section \ref{calls}.  When a
-user-defined function is called, first missing arguments for which a
-default value exists are supplied; then the arguments (a.k.a. actual
-parameters) are bound to the (formal) parameters, as follows:
-\indexii{function}{call}
-\indexiii{user-defined}{function}{call}
-\index{parameter}
-\index{argument}
-\indexii{parameter}{formal}
-\indexii{parameter}{actual}
-
-\begin{itemize}
-
-\item
-If there are no formal parameters, there must be no arguments.
-
-\item
-If the formal parameter list does not end in a star followed by an
-identifier, there must be exactly as many arguments as there are
-parameters in the formal parameter list (at the top level); the
-arguments are assigned to the formal parameters one by one.  Note that
-the presence or absence of a trailing comma at the top level in either
-the formal or the actual parameter list makes no difference.  The
-assignment to a formal parameter is performed as if the parameter
-occurs on the left hand side of an assignment statement whose right
-hand side's value is that of the argument.
-
-\item
-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
-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
-there is just one extra argument, it is a singleton tuple.
-\indexii{variable length}{parameter list}
-
-\end{itemize}
-
-Note that the `variable length parameter list' feature only works at
-the top level of the parameter list; individual parameters use a model
-corresponding more closely to that of ordinary assignment.  While the
-latter model is generally preferable, because of the greater type
-safety it offers (wrong-sized tuples aren't silently mistreated),
-variable length parameter lists are a sufficiently accepted practice
-in most programming languages that a compromise has been worked out.
-(And anyway, assignment has no equivalent for empty argument lists.)
-
-It is also possible to create anonymous functions (functions not bound
-to a name), for immediate use in expressions.  This uses lambda forms,
-described in section \ref{lambda}.
-\indexii{lambda}{form}
-
-\section{Class definitions} \label{class}
-\indexii{class}{definition}
-
-A class definition defines a class object (see section \ref{types}):
-\obindex{class}
-
-\begin{verbatim}
-classdef:       "class" classname [inheritance] ":" suite
-inheritance:    "(" [condition_list] ")"
-classname:      identifier
-\end{verbatim}
-
-A class definition is an executable statement.  It first evaluates the
-inheritance list, if present.  Each item in the inheritance list
-should evaluate to a class object.  The class's suite is then executed
-in a new execution frame (see section \ref{execframes}), using a newly
-created local name space and the original global name space.
-(Usually, the suite contains only function definitions.)  When the
-class's suite finishes execution, its execution frame is discarded but
-its local name space is saved.  A class object is then created using
-the inheritance list for the base classes and the saved local name
-space for the attribute dictionary.  The class name is bound to this
-class object in the original local name space.
-\index{inheritance}
-\indexii{class}{name}
-\indexii{name}{binding}
-\indexii{execution}{frame}