codeop — Compile Python code

Source code:Lib/codeop.py


Thecodeop module provides utilities upon which the Pythonread-eval-print loop can be emulated, as is done in thecode module. Asa result, you probably don’t want to use the module directly; if you want toinclude such a loop in your program you probably want to use thecodemodule instead.

There are two parts to this job:

  1. Being able to tell if a line of input completes a Python statement: inshort, telling whether to print ‘>>>’ or ‘...’ next.

  2. Remembering which future statements the user has entered, so subsequentinput can be compiled with these in effect.

Thecodeop module provides a way of doing each of these things, and a wayof doing them both.

To do just the former:

codeop.compile_command(source,filename='<input>',symbol='single')

Tries to compilesource, which should be a string of Python code and return acode object ifsource is valid Python code. In that case, the filenameattribute of the code object will befilename, which defaults to'<input>'. ReturnsNone ifsource isnot valid Python code, but is aprefix of valid Python code.

If there is a problem withsource, an exception will be raised.SyntaxError is raised if there is invalid Python syntax, andOverflowError orValueError if there is an invalid literal.

Thesymbol argument determines whethersource is compiled as a statement('single', the default), as a sequence ofstatement ('exec') oras anexpression ('eval'). Any other value willcauseValueError to be raised.

Note

It is possible (but not likely) that the parser stops parsing with asuccessful 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.

classcodeop.Compile

Instances of this class have__call__() methods identical in signature tothe built-in functioncompile(), but with the difference that if theinstance compiles program text containing a__future__ statement, theinstance ‘remembers’ and compiles all subsequent program texts with thestatement in force.

classcodeop.CommandCompiler

Instances of this class have__call__() methods identical in signature tocompile_command(); the difference is that if the instance compiles programtext containing a__future__ statement, the instance ‘remembers’ andcompiles all subsequent program texts with the statement in force.