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author | Guido van Rossum <guido@python.org> | 1998-07-06 13:18:39 (GMT) |
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committer | Guido van Rossum <guido@python.org> | 1998-07-06 13:18:39 (GMT) |
commit | 5f574aace94a6fba7406bcde237b43e150806f51 (patch) | |
tree | 40169eaf79078726460ab55f40f662ffaa842705 | |
parent | 9f2b5243851146f09fcaadc2dbfa97da329c8417 (diff) | |
download | cpython-5f574aace94a6fba7406bcde237b43e150806f51.zip cpython-5f574aace94a6fba7406bcde237b43e150806f51.tar.gz cpython-5f574aace94a6fba7406bcde237b43e150806f51.tar.bz2 |
Added back the description of the exec statement. It appears that I
accidentally cut it out when removing the access statement! Added a
paragraph on __builtins__ and other possible manipulations of the key
space of the dictionaries. Added some index entries.
-rw-r--r-- | Doc/ref/ref6.tex | 38 |
1 files changed, 38 insertions, 0 deletions
diff --git a/Doc/ref/ref6.tex b/Doc/ref/ref6.tex index e05d83c..80e9a71 100644 --- a/Doc/ref/ref6.tex +++ b/Doc/ref/ref6.tex @@ -509,3 +509,41 @@ containing the \keyword{exec} statement. The same applies to the \bifuncindex{eval} \bifuncindex{execfile} \bifuncindex{compile} + +\section{The {\tt exec} statement} \label{exec} +\stindex{exec} + +\begin{verbatim} +exec_stmt: "exec" expression ["in" expression ["," expression]] +\end{verbatim} + +This statement supports dynamic execution of Python code. The first +expression should evaluate to either a string, an open file object, or +a code object. If it is a string, the string is parsed as a suite of +Python statements which is then executed (unless a syntax error +occurs). If it is an open file, the file is parsed until EOF and +executed. If it is a code object, it is simply executed. + +In all cases, if the optional parts are omitted, the code is executed +in the current scope. If only the first expression after \keyword{in} +is specified, it should be a dictionary, which will be used for both +the global and the local variables. If two expressions are given, +both must be dictionaries and they are used for the global and local +variables, respectively. + +As a side effect, an implementation may insert additional keys into +the dictionaries given besides those corresponding to variable names +set by the executed code. For example, the current implementation +may add a reference to the dictionary of the built-in module +\module{__builtin__} under the key \code{__builtins__} (!). +\ttindex{__builtins__} +\refbimodindex{__builtin__} + +Hints: dynamic evaluation of expressions is supported by the built-in +function \function{eval()}. The built-in functions +\function{globals()} and \function{locals()} return the current global +and local dictionary, respectively, which may be useful to pass around +for use by \keyword{exec}. +\bifuncindex{eval} +\bifuncindex{globals} +\bifuncindex{locals} |