1:mod:`codeop` --- Compile Python code
2=====================================
3
4.. module:: codeop
5   :synopsis: Compile (possibly incomplete) Python code.
6
7.. sectionauthor:: Moshe Zadka <moshez@zadka.site.co.il>
8.. sectionauthor:: Michael Hudson <mwh@python.net>
9
10**Source code:** :source:`Lib/codeop.py`
11
12--------------
13
14The :mod:`codeop` module provides utilities upon which the Python
15read-eval-print loop can be emulated, as is done in the :mod:`code` module.  As
16a result, you probably don't want to use the module directly; if you want to
17include such a loop in your program you probably want to use the :mod:`code`
18module instead.
19
20There are two parts to this job:
21
22#. Being able to tell if a line of input completes a Python  statement: in
23   short, telling whether to print '``>>>``' or '``...``' next.
24
25#. Remembering which future statements the user has entered, so  subsequent
26   input can be compiled with these in effect.
27
28The :mod:`codeop` module provides a way of doing each of these things, and a way
29of doing them both.
30
31To do just the former:
32
33.. function:: compile_command(source, filename="<input>", symbol="single")
34
35   Tries to compile *source*, which should be a string of Python code and return a
36   code object if *source* is valid Python code. In that case, the filename
37   attribute of the code object will be *filename*, which defaults to
38   ``'<input>'``. Returns ``None`` if *source* is *not* valid Python code, but is a
39   prefix of valid Python code.
40
41   If there is a problem with *source*, an exception will be raised.
42   :exc:`SyntaxError` is raised if there is invalid Python syntax, and
43   :exc:`OverflowError` or :exc:`ValueError` if there is an invalid literal.
44
45   The *symbol* argument determines whether *source* is compiled as a statement
46   (``'single'``, the default), as a sequence of statements (``'exec'``) or
47   as an :term:`expression` (``'eval'``).  Any other value will
48   cause :exc:`ValueError` to  be raised.
49
50   .. note::
51
52      It is possible (but not likely) that the parser stops parsing with a
53      successful outcome before reaching the end of the source; in this case,
54      trailing symbols may be ignored instead of causing an error.  For example,
55      a backslash followed by two newlines may be followed by arbitrary garbage.
56      This will be fixed once the API for the parser is better.
57
58
59.. class:: Compile()
60
61   Instances of this class have :meth:`__call__` methods identical in signature to
62   the built-in function :func:`compile`, but with the difference that if the
63   instance compiles program text containing a :mod:`__future__` statement, the
64   instance 'remembers' and compiles all subsequent program texts with the
65   statement in force.
66
67
68.. class:: CommandCompiler()
69
70   Instances of this class have :meth:`__call__` methods identical in signature to
71   :func:`compile_command`; the difference is that if the instance compiles program
72   text containing a ``__future__`` statement, the instance 'remembers' and
73   compiles all subsequent program texts with the statement in force.
74