ENH: Add the ipy_pretty extension.

IPython/Extensions/ipy_pretty.py

@@ -0,0 +1,61 b''
+""" Use pretty.py for configurable pretty-printing.
+
+Register pretty-printers for types using pretty.for_type() or
+pretty.for_type_by_name(). For example, to make a pretty-printer for numpy dtype
+objects, add the following to your ipy_user_conf.py::
+
+    from IPython.Extensions import ipy_pretty, pretty
+
+    def dtype_pprinter(obj, p, cycle):
+        if cycle:
+            return p.text('dtype(...)')
+        if obj.fields is None:
+            p.text(repr(obj))
+        else:
+            p.begin_group(7, 'dtype([')
+            for i, field in enumerate(obj.descr):
+                if i > 0:
+                    p.text(',')
+                    p.breakable()
+                p.pretty(field)
+            p.end_group(7, '])')
+
+    # If you want to have numpy always imported anyways:
+    import numpy
+    pretty.for_type(numpy.dtype, dtype_pprinter)
+
+    # If you don't want to have numpy imported until it needs to be:
+    pretty.for_type_by_name('numpy', 'dtype', dtype_pprinter)
+"""
+
+import IPython.ipapi
+from IPython.genutils import Term
+
+from IPython.Extensions import pretty
+
+ip = IPython.ipapi.get()
+
+def pretty_result_display(self, arg):
+    """ Uber-pretty-printing display hook.
+
+    Called for displaying the result to the user.
+    """
+    
+    if self.rc.pprint:
+        out = pretty.pretty(arg, verbose=getattr(self.rc, 'pretty_verbose', False))
+        if '\n' in out:
+            # So that multi-line strings line up with the left column of
+            # the screen, instead of having the output prompt mess up
+            # their first line.                
+            Term.cout.write('\n')
+        print >>Term.cout, out
+    else:
+        # By default, the interactive prompt uses repr() to display results,
+        # so we should honor this.  Users who'd rather use a different
+        # mechanism can easily override this hook.
+        print >>Term.cout, repr(arg)
+    # the default display hook doesn't manipulate the value to put in history
+    return None 
+
+ip.set_hook('result_display', pretty_result_display)
+

IPython/Extensions/pretty.py

@@ -0,0 +1,699 b''
+# -*- coding: utf-8 -*-
+"""
+    pretty
+    ~~
+
+    Python advanced pretty printer.  This pretty printer is intended to
+    replace the old `pprint` python module which does not allow developers
+    to provide their own pretty print callbacks.
+
+    This module is based on ruby's `prettyprint.rb` library by `Tanaka Akira`.
+
+
+    Example Usage
+    =============
+
+    To directly print the representation of an object use `pprint`::
+
+        from pretty import pprint
+        pprint(complex_object)
+
+    To get a string of the output use `pretty`::
+
+        from pretty import pretty
+        string = pretty(complex_object)
+
+
+    Extending
+    =========
+
+    The pretty library allows developers to add pretty printing rules for their
+    own objects.  This process is straightforward.  All you have to do is to
+    add a `__pretty__` method to your object and call the methods on the
+    pretty printer passed::
+
+        class MyObject(object):
+
+            def __pretty__(self, p, cycle):
+                ...
+
+    Depending on the python version you want to support you have two
+    possibilities.  The following list shows the python 2.5 version and the
+    compatibility one.
+
+
+    Here the example implementation of a `__pretty__` method for a list
+    subclass for python 2.5 and higher (python 2.5 requires the with statement
+    __future__ import)::
+
+        class MyList(list):
+
+            def __pretty__(self, p, cycle):
+                if cycle:
+                    p.text('MyList(...)')
+                else:
+                    with p.group(8, 'MyList([', '])'):
+                        for idx, item in enumerate(self):
+                            if idx:
+                                p.text(',')
+                                p.breakable()
+                            p.pretty(item)
+
+    The `cycle` parameter is `True` if pretty detected a cycle.  You *have* to
+    react to that or the result is an infinite loop.  `p.text()` just adds
+    non breaking text to the output, `p.breakable()` either adds a whitespace
+    or breaks here.  If you pass it an argument it's used instead of the
+    default space.  `p.pretty` prettyprints another object using the pretty print
+    method.
+
+    The first parameter to the `group` function specifies the extra indentation
+    of the next line.  In this example the next item will either be not
+    breaked (if the items are short enough) or aligned with the right edge of
+    the opening bracked of `MyList`.
+
+    If you want to support python 2.4 and lower you can use this code::
+
+        class MyList(list):
+
+            def __pretty__(self, p, cycle):
+                if cycle:
+                    p.text('MyList(...)')
+                else:
+                    p.begin_group(8, 'MyList([')
+                    for idx, item in enumerate(self):
+                        if idx:
+                            p.text(',')
+                            p.breakable()
+                        p.pretty(item)
+                    p.end_group(8, '])')
+
+    If you just want to indent something you can use the group function
+    without open / close parameters.  Under python 2.5 you can also use this
+    code::
+
+        with p.indent(2):
+            ...
+
+    Or under python2.4 you might want to modify ``p.indentation`` by hand but
+    this is rather ugly.
+
+    :copyright: 2007 by Armin Ronacher.
+                Portions (c) 2009 by Robert Kern.
+    :license: BSD License.
+"""
+import __future__
+import sys
+import types
+import re
+import datetime
+from StringIO import StringIO
+from collections import deque
+
+
+__all__ = ['pretty', 'pprint', 'PrettyPrinter', 'RepresentationPrinter',
+    'for_type', 'for_type_by_name']
+
+
+_re_pattern_type = type(re.compile(''))
+
+
+def pretty(obj, verbose=False, max_width=79, newline='\n'):
+    """
+    Pretty print the object's representation.
+    """
+    stream = StringIO()
+    printer = RepresentationPrinter(stream, verbose, max_width, newline)
+    printer.pretty(obj)
+    printer.flush()
+    return stream.getvalue()
+
+
+def pprint(obj, verbose=False, max_width=79, newline='\n'):
+    """
+    Like `pretty` but print to stdout.
+    """
+    printer = RepresentationPrinter(sys.stdout, verbose, max_width, newline)
+    printer.pretty(obj)
+    printer.flush()
+    sys.stdout.write(newline)
+    sys.stdout.flush()
+
+
+# add python2.5 context managers if we have the with statement feature
+if hasattr(__future__, 'with_statement'): exec '''
+from __future__ import with_statement
+from contextlib import contextmanager
+
+class _PrettyPrinterBase(object):
+
+    @contextmanager
+    def indent(self, indent):
+        """with statement support for indenting/dedenting."""
+        self.indentation += indent
+        try:
+            yield
+        finally:
+            self.indentation -= indent
+
+    @contextmanager
+    def group(self, indent=0, open='', close=''):
+        """like begin_group / end_group but for the with statement."""
+        self.begin_group(indent, open)
+        try:
+            with self.indent(indent):
+                yield
+        finally:
+            self.end_group(indent, close)
+'''
+else:
+    class _PrettyPrinterBase(object):
+
+        def _unsupported(self, *a, **kw):
+            """unsupported operation"""
+            raise RuntimeError('not available in this python version')
+        group = indent = _unsupported
+        del _unsupported
+
+
+class PrettyPrinter(_PrettyPrinterBase):
+    """
+    Baseclass for the `RepresentationPrinter` prettyprinter that is used to
+    generate pretty reprs of objects.  Contrary to the `RepresentationPrinter`
+    this printer knows nothing about the default pprinters or the `__pretty__`
+    callback method.
+    """
+
+    def __init__(self, output, max_width=79, newline='\n'):
+        self.output = output
+        self.max_width = max_width
+        self.newline = newline
+        self.output_width = 0
+        self.buffer_width = 0
+        self.buffer = deque()
+
+        root_group = Group(0)
+        self.group_stack = [root_group]
+        self.group_queue = GroupQueue(root_group)
+        self.indentation = 0
+
+    def _break_outer_groups(self):
+        while self.max_width < self.output_width + self.buffer_width:
+            group = self.group_queue.deq()
+            if not group:
+                return
+            while group.breakables:
+                x = self.buffer.popleft()
+                self.output_width = x.output(self.output, self.output_width)
+                self.buffer_width -= x.width
+            while self.buffer and isinstance(self.buffer[0], Text):
+                x = self.buffer.popleft()
+                self.output_width = x.output(self.output, self.output_width)
+                self.buffer_width -= x.width
+
+    def text(self, obj):
+        """Add literal text to the output."""
+        width = len(obj)
+        if self.buffer:
+            text = self.buffer[-1]
+            if not isinstance(text, Text):
+                text = Text()
+                self.buffer.append(text)
+            text.add(obj, width)
+            self.buffer_width += width
+            self._break_outer_groups()
+        else:
+            self.output.write(obj)
+            self.output_width += width
+
+    def breakable(self, sep=' '):
+        """
+        Add a breakable separator to the output.  This does not mean that it
+        will automatically break here.  If no breaking on this position takes
+        place the `sep` is inserted which default to one space.
+        """
+        width = len(sep)
+        group = self.group_stack[-1]
+        if group.want_break:
+            self.flush()
+            self.output.write(self.newline)
+            self.output.write(' ' * self.indentation)
+            self.output_width = self.indentation
+            self.buffer_width = 0
+        else:
+            self.buffer.append(Breakable(sep, width, self))
+            self.buffer_width += width
+            self._break_outer_groups()
+
+
+    def begin_group(self, indent=0, open=''):
+        """
+        Begin a group.  If you want support for python < 2.5 which doesn't has
+        the with statement this is the preferred way:
+
+            p.begin_group(1, '{')
+            ...
+            p.end_group(1, '}')
+
+        The python 2.5 expression would be this:
+
+            with p.group(1, '{', '}'):
+                ...
+
+        The first parameter specifies the indentation for the next line (usually
+        the width of the opening text), the second the opening text.  All
+        parameters are optional.
+        """
+        if open:
+            self.text(open)
+        group = Group(self.group_stack[-1].depth + 1)
+        self.group_stack.append(group)
+        self.group_queue.enq(group)
+        self.indentation += indent
+
+    def end_group(self, dedent=0, close=''):
+        """End a group. See `begin_group` for more details."""
+        self.indentation -= dedent
+        group = self.group_stack.pop()
+        if not group.breakables:
+            self.group_queue.remove(group)
+        if close:
+            self.text(close)
+
+    def flush(self):
+        """Flush data that is left in the buffer."""
+        for data in self.buffer:
+            self.output_width += data.output(self.output, self.output_width)
+        self.buffer.clear()
+        self.buffer_width = 0
+
+
+def _get_mro(obj_class):
+    """ Get a reasonable method resolution order of a class and its superclasses
+    for both old-style and new-style classes.
+    """
+    if not hasattr(obj_class, '__mro__'):
+        # Old-style class. Mix in object to make a fake new-style class.
+        obj_class = type(obj_class.__name__, (obj_class, object), {})
+        mro = obj_class.__mro__[1:-1]
+    else:
+        mro = obj_class.__mro__
+    return mro
+
+
+class RepresentationPrinter(PrettyPrinter):
+    """
+    Special pretty printer that has a `pretty` method that calls the pretty
+    printer for a python object.
+
+    This class stores processing data on `self` so you must *never* use
+    this class in a threaded environment.  Always lock it or reinstanciate
+    it.
+
+    Instances also have a verbose flag callbacks can access to control their
+    output.  For example the default instance repr prints all attributes and
+    methods that are not prefixed by an underscore if the printer is in
+    verbose mode.
+    """
+
+    def __init__(self, output, verbose=False, max_width=79, newline='\n'):
+        PrettyPrinter.__init__(self, output, max_width, newline)
+        self.verbose = verbose
+        self.stack = []
+
+    def pretty(self, obj):
+        """Pretty print the given object."""
+        obj_id = id(obj)
+        cycle = obj_id in self.stack
+        self.stack.append(obj_id)
+        self.begin_group()
+        try:
+            obj_class = getattr(obj, '__class__', None) or type(obj)
+            if hasattr(obj_class, '__pretty__'):
+                return obj_class.__pretty__(obj, self, cycle)
+            try:
+                printer = _singleton_pprinters[obj_id]
+            except (TypeError, KeyError):
+                pass
+            else:
+                return printer(obj, self, cycle)
+            for cls in _get_mro(obj_class):
+                if cls in _type_pprinters:
+                    return _type_pprinters[cls](obj, self, cycle)
+                else:
+                    printer = self._in_deferred_types(cls)
+                    if printer is not None:
+                        return printer(obj, self, cycle)
+            return _default_pprint(obj, self, cycle)
+        finally:
+            self.end_group()
+            self.stack.pop()
+
+    def _in_deferred_types(self, cls):
+        """
+        Check if the given class is specified in the deferred type registry.
+
+        Returns the printer from the registry if it exists, and None if the
+        class is not in the registry. Successful matches will be moved to the
+        regular type registry for future use.
+        """
+        mod = getattr(cls, '__module__', None)
+        name = getattr(cls, '__name__', None)
+        key = (mod, name)
+        printer = None
+        if key in _deferred_type_pprinters:
+            # Move the printer over to the regular registry.
+            printer = _deferred_type_pprinters.pop(key)
+            _type_pprinters[cls] = printer
+        return printer
+
+
+
+class Printable(object):
+
+    def output(self, stream, output_width):
+        return output_width
+
+
+class Text(Printable):
+
+    def __init__(self):
+        self.objs = []
+        self.width = 0
+
+    def output(self, stream, output_width):
+        for obj in self.objs:
+            stream.write(obj)
+        return output_width + self.width
+
+    def add(self, obj, width):
+        self.objs.append(obj)
+        self.width += width
+
+
+class Breakable(Printable):
+
+    def __init__(self, seq, width, pretty):
+        self.obj = seq
+        self.width = width
+        self.pretty = pretty
+        self.indentation = pretty.indentation
+        self.group = pretty.group_stack[-1]
+        self.group.breakables.append(self)
+
+    def output(self, stream, output_width):
+        self.group.breakables.popleft()
+        if self.group.want_break:
+            stream.write(self.pretty.newline)
+            stream.write(' ' * self.indentation)
+            return self.indentation
+        if not self.group.breakables:
+            self.pretty.group_queue.remove(self.group)
+        stream.write(self.obj)
+        return output_width + self.width
+
+
+class Group(Printable):
+
+    def __init__(self, depth):
+        self.depth = depth
+        self.breakables = deque()
+        self.want_break = False
+
+
+class GroupQueue(object):
+
+    def __init__(self, *groups):
+        self.queue = []
+        for group in groups:
+            self.enq(group)
+
+    def enq(self, group):
+        depth = group.depth
+        while depth > len(self.queue) - 1:
+            self.queue.append([])
+        self.queue[depth].append(group)
+
+    def deq(self):
+        for stack in self.queue:
+            for idx, group in enumerate(reversed(stack)):
+                if group.breakables:
+                    del stack[idx]
+                    group.want_break = True
+                    return group
+            for group in stack:
+                group.want_break = True
+            del stack[:]
+
+    def remove(self, group):
+        try:
+            self.queue[group.depth].remove(group)
+        except ValueError:
+            pass
+
+
+_baseclass_reprs = (object.__repr__, types.InstanceType.__repr__)
+
+
+def _default_pprint(obj, p, cycle):
+    """
+    The default print function.  Used if an object does not provide one and
+    it's none of the builtin objects.
+    """
+    klass = getattr(obj, '__class__', None) or type(obj)
+    if getattr(klass, '__repr__', None) not in _baseclass_reprs:
+        # A user-provided repr.
+        p.text(repr(obj))
+        return
+    p.begin_group(1, '<')
+    p.pretty(klass)
+    p.text(' at 0x%x' % id(obj))
+    if cycle:
+        p.text(' ...')
+    elif p.verbose:
+        first = True
+        for key in dir(obj):
+            if not key.startswith('_'):
+                try:
+                    value = getattr(obj, key)
+                except AttributeError:
+                    continue
+                if isinstance(value, types.MethodType):
+                    continue
+                if not first:
+                    p.text(',')
+                p.breakable()
+                p.text(key)
+                p.text('=')
+                step = len(key) + 1
+                p.indentation += step
+                p.pretty(value)
+                p.indentation -= step
+                first = False
+    p.end_group(1, '>')
+
+
+def _seq_pprinter_factory(start, end):
+    """
+    Factory that returns a pprint function useful for sequences.  Used by
+    the default pprint for tuples, dicts, lists, sets and frozensets.
+    """
+    def inner(obj, p, cycle):
+        if cycle:
+            return p.text(start + '...' + end)
+        step = len(start)
+        p.begin_group(step, start)
+        for idx, x in enumerate(obj):
+            if idx:
+                p.text(',')
+                p.breakable()
+            p.pretty(x)
+        if len(obj) == 1 and type(obj) is tuple:
+            # Special case for 1-item tuples.
+            p.text(',')
+        p.end_group(step, end)
+    return inner
+
+
+def _dict_pprinter_factory(start, end):
+    """
+    Factory that returns a pprint function used by the default pprint of
+    dicts and dict proxies.
+    """
+    def inner(obj, p, cycle):
+        if cycle:
+            return p.text('{...}')
+        p.begin_group(1, start)
+        keys = obj.keys()
+        try:
+            keys.sort()
+        except Exception, e:
+            # Sometimes the keys don't sort.
+            pass
+        for idx, key in enumerate(keys):
+            if idx:
+                p.text(',')
+                p.breakable()
+            p.pretty(key)
+            p.text(': ')
+            p.pretty(obj[key])
+        p.end_group(1, end)
+    return inner
+
+
+def _super_pprint(obj, p, cycle):
+    """The pprint for the super type."""
+    p.begin_group(8, '<super: ')
+    p.pretty(obj.__self_class__)
+    p.text(',')
+    p.breakable()
+    p.pretty(obj.__self__)
+    p.end_group(8, '>')
+
+
+def _re_pattern_pprint(obj, p, cycle):
+    """The pprint function for regular expression patterns."""
+    p.text('re.compile(')
+    pattern = repr(obj.pattern)
+    if pattern[:1] in 'uU':
+        pattern = pattern[1:]
+        prefix = 'ur'
+    else:
+        prefix = 'r'
+    pattern = prefix + pattern.replace('\\\\', '\\')
+    p.text(pattern)
+    if obj.flags:
+        p.text(',')
+        p.breakable()
+        done_one = False
+        for flag in ('TEMPLATE', 'IGNORECASE', 'LOCALE', 'MULTILINE', 'DOTALL',
+            'UNICODE', 'VERBOSE', 'DEBUG'):
+            if obj.flags & getattr(re, flag):
+                if done_one:
+                    p.text('|')
+                p.text('re.' + flag)
+                done_one = True
+    p.text(')')
+
+
+def _type_pprint(obj, p, cycle):
+    """The pprint for classes and types."""
+    if obj.__module__ in ('__builtin__', 'exceptions'):
+        name = obj.__name__
+    else:
+        name = obj.__module__ + '.' + obj.__name__
+    p.text(name)
+
+
+def _repr_pprint(obj, p, cycle):
+    """A pprint that just redirects to the normal repr function."""
+    p.text(repr(obj))
+
+
+def _function_pprint(obj, p, cycle):
+    """Base pprint for all functions and builtin functions."""
+    if obj.__module__ in ('__builtin__', 'exceptions') or not obj.__module__:
+        name = obj.__name__
+    else:
+        name = obj.__module__ + '.' + obj.__name__
+    p.text('<function %s>' % name)
+
+
+def _exception_pprint(obj, p, cycle):
+    """Base pprint for all exceptions."""
+    if obj.__class__.__module__ == 'exceptions':
+        name = obj.__class__.__name__
+    else:
+        name = '%s.%s' % (
+            obj.__class__.__module__,
+            obj.__class__.__name__
+        )
+    step = len(name) + 1
+    p.begin_group(step, '(')
+    for idx, arg in enumerate(getattr(obj, 'args', ())):
+        if idx:
+            p.text(',')
+            p.breakable()
+        p.pretty(arg)
+    p.end_group(step, ')')
+
+
+#: the exception base
+try:
+    _exception_base = BaseException
+except NameError:
+    _exception_base = Exception
+
+
+#: printers for builtin types
+_type_pprinters = {
+    int:                        _repr_pprint,
+    long:                       _repr_pprint,
+    float:                      _repr_pprint,
+    str:                        _repr_pprint,
+    unicode:                    _repr_pprint,
+    tuple:                      _seq_pprinter_factory('(', ')'),
+    list:                       _seq_pprinter_factory('[', ']'),
+    dict:                       _dict_pprinter_factory('{', '}'),
+    types.DictProxyType:        _dict_pprinter_factory('<dictproxy {', '}>'),
+    set:                        _seq_pprinter_factory('set([', '])'),
+    frozenset:                  _seq_pprinter_factory('frozenset([', '])'),
+    super:                      _super_pprint,
+    _re_pattern_type:           _re_pattern_pprint,
+    type:                       _type_pprint,
+    types.ClassType:            _type_pprint,
+    types.FunctionType:         _function_pprint,
+    types.BuiltinFunctionType:  _function_pprint,
+    types.SliceType:            _repr_pprint,
+    types.MethodType:           _repr_pprint,
+    xrange:                     _repr_pprint,
+    datetime.datetime:          _repr_pprint,
+    datetime.timedelta:         _repr_pprint,
+    _exception_base:            _exception_pprint
+}
+
+#: printers for types specified by name
+_deferred_type_pprinters = {
+}
+
+def for_type(typ, func):
+    """
+    Add a pretty printer for a given type.
+    """
+    oldfunc = _type_pprinters.get(typ, None)
+    if func is not None:
+        # To support easy restoration of old pprinters, we need to ignore Nones.
+        _type_pprinters[typ] = func
+    return oldfunc
+
+def for_type_by_name(type_module, type_name, func):
+    """
+    Add a pretty printer for a type specified by the module and name of a type
+    rather than the type object itself.
+    """
+    key = (type_module, type_name)
+    oldfunc = _deferred_type_pprinters.get(key, None)
+    if func is not None:
+        # To support easy restoration of old pprinters, we need to ignore Nones.
+        _deferred_type_pprinters[key] = func
+    return oldfunc
+
+
+#: printers for the default singletons
+_singleton_pprinters = dict.fromkeys(map(id, [None, True, False, Ellipsis,
+                                      NotImplemented]), _repr_pprint)
+
+
+if __name__ == '__main__':
+    from random import randrange
+    class Foo(object):
+        def __init__(self):
+            self.foo = 1
+            self.bar = re.compile(r'\s+')
+            self.blub = dict.fromkeys(range(30), randrange(1, 40))
+            self.hehe = 23424.234234
+            self.list = ["blub", "blah", self]
+
+        def get_foo(self):
+            print "foo"
+
+    pprint(Foo(), verbose=True)