:mod:codeop --- Compile Python code

.. module:: codeop :synopsis: Compile (possibly incomplete) Python code.

.. sectionauthor:: Moshe Zadka [email protected] .. sectionauthor:: Michael Hudson [email protected]

Source code: :source:Lib/codeop.py

The :mod:codeop module provides utilities upon which the Python read-eval-print loop can be emulated, as is done in the :mod:code module. As a result, you probably don't want to use the module directly; if you want to include such a loop in your program you probably want to use the :mod:code module instead.

There are two parts to this job:

#. Being able to tell if a line of input completes a Python statement: in short, telling whether to print '>>>' or '...' next.

#. Remembering which future statements the user has entered, so subsequent input can be compiled with these in effect.

The :mod:codeop module provides a way of doing each of these things, and a way of doing them both.

To do just the former:

.. function:: compile_command(source, filename="<input>", symbol="single")

Tries to compile source, which should be a string of Python code and return a code object if source is valid Python code. In that case, the filename attribute of the code object will be filename, which defaults to '<input>'. Returns None if source is not valid Python code, but is a prefix of valid Python code.

If there is a problem with source, an exception will be raised. :exc:SyntaxError is raised if there is invalid Python syntax, and :exc:OverflowError or :exc:ValueError if there is an invalid literal.

The symbol argument determines whether source is compiled as a statement ('single', the default) or as an :term:expression ('eval'). Any other value will cause :exc:ValueError to be raised.

.. note::

  It is possible (but not likely) that the parser stops parsing with a
  successful outcome before reaching the end of the source; in this case,
  trailing symbols may be ignored instead of causing an error.  For example,
  a backslash followed by two newlines may be followed by arbitrary garbage.
  This will be fixed once the API for the parser is better.

.. class:: Compile()

Instances of this class have :meth:__call__ methods identical in signature to the built-in function :func:compile, but with the difference that if the instance compiles program text containing a :mod:__future__ statement, the instance 'remembers' and compiles all subsequent program texts with the statement in force.

.. class:: CommandCompiler()

Instances of this class have :meth:__call__ methods identical in signature to :func:compile_command; the difference is that if the instance compiles program text containing a __future__ statement, the instance 'remembers' and compiles all subsequent program texts with the statement in force.