pythonrc

# -*- coding: utf-8 -*-
"""Startup script that adds niceties to the interactive interpreter.

This script adds the following things:

- Readline bindings, tab completion, and history (in ~/.history/python,
  which can be disabled by setting NOHIST in the environment)

- Pretty printing of expression output (with Pygments highlighting)

- Pygments highlighting of tracebacks

- Function arguments in repr() for callables

- A source() function that displays the source of an arbitrary object
  (in a pager, with Pygments highlighting)

Python 2.3 and newer are supported, including Python 3.x.

Note: The default versions of Python that ship with Mac OS X don't
come with readline. To get readline support, you can try a stand-alone
readline library[1], or you can use a different Python distribution
(like the one from MacPorts).

[1]: http://pypi.python.org/pypi/readline
"""


def _pythonrc_enable_readline():
    """Enable readline, tab completion, and history"""
    import sys

    try:
        import readline
        import rlcompleter
    except ImportError:
        sys.stderr.write('readline unavailable - tab completion disabled.\n')
        return

    old_complete = readline.get_completer()

    def complete(text, state):
        if not text:
            # Insert four spaces for indentation
            return ('    ', None)[state]
        else:
            return old_complete(text, state)
    readline.parse_and_bind('tab: complete')
    readline.set_completer(complete)


def _pythonrc_enable_history():
    import atexit
    import os
    try:
        import readline
    except:
        return

    # "NOHIST= python" will disable history
    if 'NOHIST' not in os.environ:
        history_path = os.path.expanduser('~/.python/history')

        has_written = [False]

        def write_history():
            if not has_written[0]:
                readline.write_history_file(history_path)
                print('Written history to %s' % history_path)
                has_written[0] = True
        atexit.register(write_history)

        if os.path.isfile(history_path):
            try:
                readline.read_history_file(history_path)
            except IOError:
                pass

        readline.set_history_length(-1)


def _pythonrc_enable_pprint():
    """Enable pretty printing of evaluated expressions"""
    import pprint
    import sys

    try:
        if sys.platform == 'win32':
            raise ImportError()
        from cStringIO import StringIO
        from pygments import highlight
        from pygments.lexers import PythonLexer, PythonTracebackLexer
        from pygments.formatters import TerminalFormatter

        def pphighlight(o, *a, **kw):
            s = pprint.pformat(o, *a, **kw)
            try:
                sys.stdout.write(
                    highlight(s, PythonLexer(), TerminalFormatter()))
            except UnicodeError:
                sys.stdout.write(s)
                sys.stdout.write('\n')

        _old_excepthook = sys.excepthook

        def excepthook(exctype, value, traceback):
            """Prints exceptions to sys.stderr and colorizes them"""

            # traceback.format_exception() isn't used because it's
            # inconsistent with the built-in formatter
            old_stderr = sys.stderr
            sys.stderr = StringIO()
            try:
                _old_excepthook(exctype, value, traceback)
                s = sys.stderr.getvalue()
                try:
                    s = highlight(
                        s, PythonTracebackLexer(), TerminalFormatter())
                except UnicodeError:
                    pass
                old_stderr.write(s)
            finally:
                sys.stderr = old_stderr

        sys.excepthook = excepthook
    except ImportError:
        pphighlight = pprint.pprint

    try:
        import __builtin__
    except ImportError:
        import builtins as __builtin__
    import inspect
    import pydoc
    import sys
    import types

    help_types = [types.BuiltinFunctionType, types.BuiltinMethodType,
                  types.FunctionType, types.MethodType, types.ModuleType,
                  type,
                  # method_descriptor
                  type(list.remove)]
    if hasattr(types, 'UnboundMethodType'):
        help_types.append(types.UnboundMethodType)
    help_types = tuple(help_types)

    def _ioctl_width(fd):

        from fcntl import ioctl
        from struct import pack, unpack
        from termios import TIOCGWINSZ
        return unpack('HHHH',
                      ioctl(fd, TIOCGWINSZ, pack('HHHH', 0, 0, 0, 0)))[1]

    def get_width():
        """Returns terminal width"""

        width = 0
        try:
            width = _ioctl_width(0) or _ioctl_width(1) or _ioctl_width(2)
        except ImportError:
            pass
        if not width:
            import os
            width = os.environ.get('COLUMNS', 0)
        return width

    if hasattr(inspect, 'getfullargspec'):
        getargspec = inspect.getfullargspec
    else:
        getargspec = inspect.getargspec

    def pprinthook(value):
        """Pretty print an object to sys.stdout and also save it in
        __builtin__.
        """

        if value is None:
            return
        __builtin__._ = value

        if isinstance(value, help_types):
            reprstr = repr(value)
            try:
                if inspect.isfunction(value):
                    parts = reprstr.split(' ')
                    parts[1] += inspect.formatargspec(*getargspec(value))
                    reprstr = ' '.join(parts)
                elif inspect.ismethod(value):
                    parts = reprstr[:-1].split(' ')
                    parts[2] += inspect.formatargspec(*getargspec(value))
                    reprstr = ' '.join(parts) + '>'
            except TypeError:
                pass
            sys.stdout.write(reprstr)
            sys.stdout.write('\n')
            if getattr(value, '__doc__', None):
                sys.stdout.write('\n')
                sys.stdout.write(pydoc.getdoc(value))
                sys.stdout.write('\n')
        else:
            pphighlight(value, width=get_width() or 80)

    sys.displayhook = pprinthook


def _pythonrc_fix_linecache():
    """Add source(obj) that shows the source code for a given object"""
    import os
    import sys
    from linecache import cache

    # linecache.updatecache() replacement that actually works with zips.
    # See http://bugs.python.org/issue4223 for more information.
    def updatecache(filename, module_globals=None):
        """Update a cache entry and return its list of lines.
        If something's wrong, print a message, discard the cache entry,
        and return an empty list."""

        if filename in cache:
            del cache[filename]
        if not filename or filename[0] + filename[-1] == '<>':
            return []

        fullname = filename
        try:
            stat = os.stat(fullname)
        except os.error:
            basename = os.path.split(filename)[1]

            if module_globals and '__loader__' in module_globals:
                name = module_globals.get('__name__')
                loader = module_globals['__loader__']
                get_source = getattr(loader, 'get_source', None)

                if name and get_source:
                    try:
                        data = get_source(name)
                    except (ImportError, IOError):
                        pass
                    else:
                        if data is None:
                            return []
                        cache[filename] = (
                            len(data), None,
                            [line + '\n' for line in data.splitlines()],
                            fullname
                        )
                        return cache[filename][2]

            for dirname in sys.path:
                try:
                    fullname = os.path.join(dirname, basename)
                except (TypeError, AttributeError):
                    pass
                else:
                    try:
                        stat = os.stat(fullname)
                        break
                    except os.error:
                        pass
            else:
                return []
        try:
            fp = open(fullname, 'rU')
            lines = fp.readlines()
            fp.close()
        except IOError:
            return []
        size, mtime = stat.st_size, stat.st_mtime
        cache[filename] = size, mtime, lines, fullname
        return lines

    import linecache
    linecache.updatecache = updatecache


def source(obj):
    """Display the source code of an object.

    Applies syntax highlighting if Pygments is available.
    """
    import os
    import sys
    from inspect import findsource, getmodule, getsource, getsourcefile
    from pydoc import pager

    try:
        # Check to see if the object is defined in a shared library, which
        # findsource() doesn't do properly (see issue4050)
        if not getsourcefile(obj):
            raise TypeError
        s = getsource(obj)
    except TypeError:
        sys.stderr.write("Source code unavailable (maybe it's part of "
                         "a C extension?)\n")
        return

    # Detect the module's file encoding. We could use
    # tokenize.detect_encoding(), but it's only available in Python 3.
    import re
    enc = 'ascii'
    for line in findsource(getmodule(obj))[0][:2]:
        m = re.search(r'coding[:=]\s*([-\w.]+)', line)
        if m:
            enc = m.group(1)
    if hasattr(s, 'decode'):
        try:
            s = s.decode(enc, 'replace')
        except LookupError:
            s = s.decode('ascii', 'replace')

    try:
        # For now, let's assume we'll never have a proper terminal on win32
        if sys.platform == 'win32':
            raise ImportError
        from pygments import highlight
        from pygments.lexers import PythonLexer
        from pygments.formatters import TerminalFormatter
        s = highlight(s, PythonLexer(), TerminalFormatter())
    except (ImportError, UnicodeError):
        pass

    # Display the source code in the pager, and try to convince less not to
    # escape color control codes.
    has_lessopts = 'LESS' in os.environ
    lessopts = os.environ.get('LESS', '')
    try:
        os.environ['LESS'] = lessopts + ' -R'
        if hasattr(s, 'decode'):
            pager(s.encode(sys.stdout.encoding, 'replace'))
        else:
            pager(s)
    finally:
        if has_lessopts:
            os.environ['LESS'] = lessopts
        else:
            os.environ.pop('LESS', None)

if __name__ == '__main__':
    __doc__ = None

    # Make sure modules in the current directory can't interfere
    import sys
    try:
        try:
            cwd = sys.path.index('')
            sys.path.pop(cwd)
        except ValueError:
            cwd = None

        sys.ps1 = '\001\033[32m\002>>> \001\033[0m\002'
        sys.ps2 = "\001\033[32m\002... \001\033[1;37m\002"

        # Run installation functions and don't taint the global namespace
        try:
            try:
                import jedi.utils
                jedi.utils.setup_readline()
                del jedi
            except:
                print('No jedi here. Coming to the dark side.')
                _pythonrc_enable_readline()
                del _pythonrc_enable_readline

            _pythonrc_enable_history()
            _pythonrc_enable_pprint()
            _pythonrc_fix_linecache()

            del _pythonrc_enable_history
            del _pythonrc_enable_pprint
            del _pythonrc_fix_linecache
        finally:
            if cwd is not None:
                sys.path.insert(cwd, '')
            del cwd
    finally:
        pass