Backport PR #4085 : Fix nbconvert date formats for Windows.

IPython/nbconvert/exporters/exporter.py

@@ -1,518 +1,518 b''
 """This module defines Exporter, a highly configurable converter
 that uses Jinja2 to export notebook files into different formats.
 """
 
 #-----------------------------------------------------------------------------
 # Copyright (c) 2013, the IPython Development Team.
 #
 # Distributed under the terms of the Modified BSD License.
 #
 # The full license is in the file COPYING.txt, distributed with this software.
 #-----------------------------------------------------------------------------
 
 #-----------------------------------------------------------------------------
 # Imports
 #-----------------------------------------------------------------------------
 
 from __future__ import print_function, absolute_import
 
 # Stdlib imports
 import io
 import os
 import inspect
 import copy
 import collections
 import datetime
 
 # other libs/dependencies
 from jinja2 import Environment, FileSystemLoader, ChoiceLoader, TemplateNotFound
 
 # IPython imports
 from IPython.config.configurable import LoggingConfigurable
 from IPython.config import Config
 from IPython.nbformat import current as nbformat
 from IPython.utils.traitlets import MetaHasTraits, DottedObjectName, Unicode, List, Dict, Any
 from IPython.utils.importstring import import_item
-from IPython.utils.text import indent
+from IPython.utils import text
 from IPython.utils import py3compat
 
 from IPython.nbconvert import transformers as nbtransformers
 from IPython.nbconvert import filters
 
 #-----------------------------------------------------------------------------
 # Globals and constants
 #-----------------------------------------------------------------------------
 
 #Jinja2 extensions to load.
 JINJA_EXTENSIONS = ['jinja2.ext.loopcontrols']
 
 default_filters = {
-        'indent': indent,
+        'indent': text.indent,
         'markdown2html': filters.markdown2html,
         'ansi2html': filters.ansi2html,
         'filter_data_type': filters.DataTypeFilter,
         'get_lines': filters.get_lines,
         'highlight2html': filters.highlight2html,
         'highlight2latex': filters.highlight2latex,
         'ipython2python': filters.ipython2python,
         'posix_path': filters.posix_path,
         'markdown2latex': filters.markdown2latex,
         'markdown2rst': filters.markdown2rst,
         'comment_lines': filters.comment_lines,
         'strip_ansi': filters.strip_ansi,
         'strip_dollars': filters.strip_dollars,
         'strip_files_prefix': filters.strip_files_prefix,
         'html2text' : filters.html2text,
         'add_anchor': filters.add_anchor,
         'ansi2latex': filters.ansi2latex,
         'strip_math_space': filters.strip_math_space,
         'wrap_text': filters.wrap_text,
         'escape_latex': filters.escape_latex,
 }
 
 #-----------------------------------------------------------------------------
 # Class
 #-----------------------------------------------------------------------------
 
 class ResourcesDict(collections.defaultdict):
     def __missing__(self, key):
         return ''
 
 
 class Exporter(LoggingConfigurable):
     """
     Exports notebooks into other file formats.  Uses Jinja 2 templating engine
     to output new formats.  Inherit from this class if you are creating a new
     template type along with new filters/transformers.  If the filters/
     transformers provided by default suffice, there is no need to inherit from
     this class.  Instead, override the template_file and file_extension
     traits via a config file.
 
     {filters}
     """
     
     # finish the docstring
     __doc__ = __doc__.format(filters = '- '+'\n    - '.join(default_filters.keys()))
 
 
     template_file = Unicode(u'default',
             config=True,
             help="Name of the template file to use")
     def _template_file_changed(self, name, old, new):
         if new=='default':
             self.template_file = self.default_template
         else:
             self.template_file = new
         self.template = None
         self._load_template()
     
     default_template = Unicode(u'')
     template = Any()
     environment = Any()
 
     file_extension = Unicode(
         'txt', config=True, 
         help="Extension of the file that should be written to disk"
         )
 
     template_path = List(['.'], config=True)
     def _template_path_changed(self, name, old, new):
         self._load_template()
 
     default_template_path = Unicode(
         os.path.join("..", "templates"), 
         help="Path where the template files are located.")
 
     template_skeleton_path = Unicode(
         os.path.join("..", "templates", "skeleton"), 
         help="Path where the template skeleton files are located.") 
 
     #Jinja block definitions
     jinja_comment_block_start = Unicode("", config=True)
     jinja_comment_block_end = Unicode("", config=True)
     jinja_variable_block_start = Unicode("", config=True)
     jinja_variable_block_end = Unicode("", config=True)
     jinja_logic_block_start = Unicode("", config=True)
     jinja_logic_block_end = Unicode("", config=True)
     
     #Extension that the template files use.    
     template_extension = Unicode(".tpl", config=True)
 
     #Configurability, allows the user to easily add filters and transformers.
     transformers = List(config=True,
         help="""List of transformers, by name or namespace, to enable.""")
 
     filters = Dict(config=True,
         help="""Dictionary of filters, by name and namespace, to add to the Jinja
         environment.""")
 
     default_transformers = List([nbtransformers.coalesce_streams,
                                  nbtransformers.SVG2PDFTransformer,
                                  nbtransformers.ExtractOutputTransformer,
                                  nbtransformers.CSSHTMLHeaderTransformer,
                                  nbtransformers.RevealHelpTransformer,
                                  nbtransformers.LatexTransformer,
                                  nbtransformers.SphinxTransformer],
         config=True,
         help="""List of transformers available by default, by name, namespace, 
         instance, or type.""")
 
 
     def __init__(self, config=None, extra_loaders=None, **kw):
         """
         Public constructor
     
         Parameters
         ----------
         config : config
             User configuration instance.
         extra_loaders : list[of Jinja Loaders]
             ordered list of Jinja loader to find templates. Will be tried in order
             before the default FileSystem ones.
         template : str (optional, kw arg)
             Template to use when exporting.
         """
         if not config:
             config = self.default_config
         
         super(Exporter, self).__init__(config=config, **kw)
 
         #Init
         self._init_template()
         self._init_environment(extra_loaders=extra_loaders)
         self._init_transformers()
         self._init_filters()
 
 
     @property
     def default_config(self):
         return Config()
     
     def _config_changed(self, name, old, new):
         """When setting config, make sure to start with our default_config"""
         c = self.default_config
         if new:
             c.merge(new)
         if c != old:
             self.config = c
         super(Exporter, self)._config_changed(name, old, c)
         
 
     def _load_template(self):
         """Load the Jinja template object from the template file
         
         This is a no-op if the template attribute is already defined,
         or the Jinja environment is not setup yet.
         
         This is triggered by various trait changes that would change the template.
         """
         if self.template is not None:
             return
         # called too early, do nothing
         if self.environment is None:
             return
         # Try different template names during conversion.  First try to load the
         # template by name with extension added, then try loading the template
         # as if the name is explicitly specified, then try the name as a 
         # 'flavor', and lastly just try to load the template by module name.
         module_name = self.__module__.rsplit('.', 1)[-1]
         try_names = []
         if self.template_file:
             try_names.extend([
                 self.template_file + self.template_extension,
                 self.template_file,
                 module_name + '_' + self.template_file + self.template_extension,
             ])
         try_names.append(module_name + self.template_extension)
         for try_name in try_names:
             self.log.debug("Attempting to load template %s", try_name)
             try:
                 self.template = self.environment.get_template(try_name)
             except (TemplateNotFound, IOError):
                 pass
             except Exception as e:
                 self.log.warn("Unexpected exception loading template: %s", try_name, exc_info=True)
             else:
                 self.log.info("Loaded template %s", try_name)
                 break
     
     def from_notebook_node(self, nb, resources=None, **kw):
         """
         Convert a notebook from a notebook node instance.
     
         Parameters
         ----------
         nb : Notebook node
         resources : dict (**kw) 
             of additional resources that can be accessed read/write by 
             transformers and filters.
         """
         nb_copy = copy.deepcopy(nb)
         resources = self._init_resources(resources)
 
         # Preprocess
         nb_copy, resources = self._transform(nb_copy, resources)
 
         self._load_template()
 
         if self.template is not None:
             output = self.template.render(nb=nb_copy, resources=resources)
         else:
             raise IOError('template file "%s" could not be found' % self.template_file)
         return output, resources
 
 
     def from_filename(self, filename, resources=None, **kw):
         """
         Convert a notebook from a notebook file.
     
         Parameters
         ----------
         filename : str
             Full filename of the notebook file to open and convert.
         """
 
         #Pull the metadata from the filesystem.
         if resources is None:
             resources = ResourcesDict()
         if not 'metadata' in resources or resources['metadata'] == '':
             resources['metadata'] = ResourcesDict()
         basename = os.path.basename(filename)
         notebook_name = basename[:basename.rfind('.')]
         resources['metadata']['name'] = notebook_name
 
         modified_date = datetime.datetime.fromtimestamp(os.path.getmtime(filename))
-        resources['metadata']['modified_date'] = modified_date.strftime("%B %d, %Y")
+        resources['metadata']['modified_date'] = modified_date.strftime(text.date_format)
         
         with io.open(filename) as f:
             return self.from_notebook_node(nbformat.read(f, 'json'), resources=resources,**kw)
 
 
     def from_file(self, file_stream, resources=None, **kw):
         """
         Convert a notebook from a notebook file.
     
         Parameters
         ----------
         file_stream : file-like object
             Notebook file-like object to convert.
         """
         return self.from_notebook_node(nbformat.read(file_stream, 'json'), resources=resources, **kw)
 
 
     def register_transformer(self, transformer, enabled=False):
         """
         Register a transformer.
         Transformers are classes that act upon the notebook before it is
         passed into the Jinja templating engine.  Transformers are also
         capable of passing additional information to the Jinja
         templating engine.
     
         Parameters
         ----------
         transformer : transformer
         """
         if transformer is None:
             raise TypeError('transformer')
         isclass = isinstance(transformer, type)
         constructed = not isclass
 
         #Handle transformer's registration based on it's type
         if constructed and isinstance(transformer, py3compat.string_types):
             #Transformer is a string, import the namespace and recursively call
             #this register_transformer method
             transformer_cls = import_item(transformer)
             return self.register_transformer(transformer_cls, enabled)
         
         if constructed and hasattr(transformer, '__call__'):
             #Transformer is a function, no need to construct it.
             #Register and return the transformer.
             if enabled:
                 transformer.enabled = True
             self._transformers.append(transformer)
             return transformer
 
         elif isclass and isinstance(transformer, MetaHasTraits):
             #Transformer is configurable.  Make sure to pass in new default for 
             #the enabled flag if one was specified.
             self.register_transformer(transformer(parent=self), enabled)
 
         elif isclass:
             #Transformer is not configurable, construct it
             self.register_transformer(transformer(), enabled)
 
         else:
             #Transformer is an instance of something without a __call__ 
             #attribute.  
             raise TypeError('transformer')
 
 
     def register_filter(self, name, jinja_filter):
         """
         Register a filter.
         A filter is a function that accepts and acts on one string.  
         The filters are accesible within the Jinja templating engine.
     
         Parameters
         ----------
         name : str
             name to give the filter in the Jinja engine
         filter : filter
         """
         if jinja_filter is None:
             raise TypeError('filter')
         isclass = isinstance(jinja_filter, type)
         constructed = not isclass
 
         #Handle filter's registration based on it's type
         if constructed and isinstance(jinja_filter, py3compat.string_types):
             #filter is a string, import the namespace and recursively call
             #this register_filter method
             filter_cls = import_item(jinja_filter)
             return self.register_filter(name, filter_cls)
         
         if constructed and hasattr(jinja_filter, '__call__'):
             #filter is a function, no need to construct it.
             self.environment.filters[name] = jinja_filter
             return jinja_filter
 
         elif isclass and isinstance(jinja_filter, MetaHasTraits):
             #filter is configurable.  Make sure to pass in new default for 
             #the enabled flag if one was specified.
             filter_instance = jinja_filter(parent=self)
             self.register_filter(name, filter_instance )
 
         elif isclass:
             #filter is not configurable, construct it
             filter_instance = jinja_filter()
             self.register_filter(name, filter_instance)
 
         else:
             #filter is an instance of something without a __call__ 
             #attribute.  
             raise TypeError('filter')
 
         
     def _init_template(self):
         """
         Make sure a template name is specified.  If one isn't specified, try to
         build one from the information we know.
         """
         self._template_file_changed('template_file', self.template_file, self.template_file)
         
 
     def _init_environment(self, extra_loaders=None):
         """
         Create the Jinja templating environment.
         """
         here = os.path.dirname(os.path.realpath(__file__))
         loaders = []
         if extra_loaders:
             loaders.extend(extra_loaders)
 
         paths = self.template_path
         paths.extend([os.path.join(here, self.default_template_path),
                       os.path.join(here, self.template_skeleton_path)])
         loaders.append(FileSystemLoader(paths))
 
         self.environment = Environment(
             loader= ChoiceLoader(loaders),
             extensions=JINJA_EXTENSIONS
             )
         
         #Set special Jinja2 syntax that will not conflict with latex.
         if self.jinja_logic_block_start:
             self.environment.block_start_string = self.jinja_logic_block_start
         if self.jinja_logic_block_end:
             self.environment.block_end_string = self.jinja_logic_block_end
         if self.jinja_variable_block_start:
             self.environment.variable_start_string = self.jinja_variable_block_start
         if self.jinja_variable_block_end:
             self.environment.variable_end_string = self.jinja_variable_block_end
         if self.jinja_comment_block_start:
             self.environment.comment_start_string = self.jinja_comment_block_start
         if self.jinja_comment_block_end:
             self.environment.comment_end_string = self.jinja_comment_block_end
 
     
     def _init_transformers(self):
         """
         Register all of the transformers needed for this exporter, disabled
         unless specified explicitly.
         """
         self._transformers = []
 
         #Load default transformers (not necessarly enabled by default).
         if self.default_transformers:
             for transformer in self.default_transformers:
                 self.register_transformer(transformer)
 
         #Load user transformers.  Enable by default.
         if self.transformers:
             for transformer in self.transformers:
                 self.register_transformer(transformer, enabled=True)
  
 
     def _init_filters(self):
         """
         Register all of the filters required for the exporter.
         """
         
         #Add default filters to the Jinja2 environment
         for key, value in default_filters.items():
             self.register_filter(key, value)
 
         #Load user filters.  Overwrite existing filters if need be.
         if self.filters:
             for key, user_filter in self.filters.items():
                 self.register_filter(key, user_filter)
 
 
     def _init_resources(self, resources):
 
         #Make sure the resources dict is of ResourcesDict type.
         if resources is None:
             resources = ResourcesDict()
         if not isinstance(resources, ResourcesDict):
             new_resources = ResourcesDict()
             new_resources.update(resources)
             resources = new_resources 
 
         #Make sure the metadata extension exists in resources
         if 'metadata' in resources:
             if not isinstance(resources['metadata'], ResourcesDict):
                 resources['metadata'] = ResourcesDict(resources['metadata'])
         else:
             resources['metadata'] = ResourcesDict()
             if not resources['metadata']['name']: 
                 resources['metadata']['name'] = 'Notebook'
 
         #Set the output extension
         resources['output_extension'] = self.file_extension
         return resources
         
 
     def _transform(self, nb, resources):
         """
         Preprocess the notebook before passing it into the Jinja engine.
         To preprocess the notebook is to apply all of the 
     
         Parameters
         ----------
         nb : notebook node
             notebook that is being exported.
         resources : a dict of additional resources that
             can be accessed read/write by transformers
             and filters.
         """
         
         # Do a copy.deepcopy first, 
         # we are never safe enough with what the transformers could do.
         nbc =  copy.deepcopy(nb)
         resc = copy.deepcopy(resources)
 
         #Run each transformer on the notebook.  Carry the output along
         #to each transformer
         for transformer in self._transformers:
             nbc, resc = transformer(nbc, resc)
         return nbc, resc

IPython/nbconvert/transformers/sphinx.py

@@ -1,264 +1,265 b''
 """Module that allows custom Sphinx parameters to be set on the notebook and
 on the 'other' object passed into Jinja.  Called prior to Jinja conversion
 process.
 """
 #-----------------------------------------------------------------------------
 # Copyright (c) 2013, the IPython Development Team.
 #
 # Distributed under the terms of the Modified BSD License.
 #
 # The full license is in the file COPYING.txt, distributed with this software.
 #-----------------------------------------------------------------------------
 
 #-----------------------------------------------------------------------------
 # Imports
 #-----------------------------------------------------------------------------
 
 from __future__ import print_function, absolute_import
 
 # Stdlib imports
 import os.path
 
 # Used to set the default date to today's date 
 from datetime import date 
 
 # Third-party imports
 # Needed for Pygments latex definitions.
 from pygments.formatters import LatexFormatter
 
 # Our own imports
 # Configurable traitlets
 from IPython.utils.traitlets import Unicode, Bool
+from IPython.utils import text
 
 # Needed to override transformer
 from .base import (Transformer)
 
 from IPython.nbconvert.utils import console  
 
 #-----------------------------------------------------------------------------
 # Classes and functions
 #-----------------------------------------------------------------------------
 
 class SphinxTransformer(Transformer):
     """
     Sphinx utility transformer.
 
     This transformer is used to set variables needed by the latex to build
     Sphinx stylized templates.
     """
     
     interactive = Bool(False, config=True, help="""
         Allows you to define whether or not the Sphinx exporter will prompt
         you for input during the conversion process.  If this is set to false,
         the author, version, release, date, and chapter_style traits should
         be set.
         """)
     
     author = Unicode("Unknown Author", config=True, help="Author name")
     
     version = Unicode("", config=True, help="""
         Version number
         You can leave this blank if you do not want to render a version number.
         Example: "1.0.0"
         """)
     
     release = Unicode("", config=True, help="""
         Release name
         You can leave this blank if you do not want to render a release name.
         Example: "Rough Draft"
         """)
     
     publish_date = Unicode("", config=True, help="""
         Publish date
         This is the date to render on the document as the publish date.
         Leave this blank to default to todays date.  
         Example: "June 12, 1990"
         """)
     
     chapter_style = Unicode("Bjarne", config=True, help="""
         Sphinx chapter style
         This is the style to use for the chapter headers in the document.
         You may choose one of the following:
             "Bjarne"    (default)
             "Lenny"
             "Glenn"
             "Conny"
             "Rejne"
             "Sonny"    (used for international documents)
         """)
     
     output_style = Unicode("notebook", config=True, help="""
         Nbconvert Ipython
         notebook input/output formatting style.
         You may choose one of the following:
             "simple     (recommended for long code segments)"
             "notebook"  (default)
         """)
     
     center_output = Bool(False, config=True, help="""
         Optional attempt to center all output.  If this is false, no additional
         formatting is applied.
         """)
     
     use_headers = Bool(True, config=True, help="""
         Whether not a header should be added to the document.
         """)
     
     #Allow the user to override the title of the notebook (useful for
     #fancy document titles that the file system doesn't support.)
     overridetitle = Unicode("", config=True, help="")
 
     
     def call(self, nb, resources):
         """
         Sphinx transformation to apply on each notebook.
         
         Parameters
         ----------
         nb : NotebookNode
             Notebook being converted
         resources : dictionary
             Additional resources used in the conversion process.  Allows
             transformers to pass variables into the Jinja engine.
         """
         # import sphinx here, so that sphinx is not a dependency when it's not used
         import sphinx
          
         # TODO: Add versatile method of additional notebook metadata.  Include
         #       handling of multiple files.  For now use a temporay namespace,
         #       '_draft' to signify that this needs to change.
         if not "sphinx" in resources:
             resources["sphinx"] = {}
 
         if self.interactive:
             
             # Prompt the user for additional meta data that doesn't exist currently
             # but would be usefull for Sphinx.
             resources["sphinx"]["author"] = self._prompt_author()
             resources["sphinx"]["version"] = self._prompt_version()
             resources["sphinx"]["release"] = self._prompt_release()
             resources["sphinx"]["date"] = self._prompt_date()
             
             # Prompt the user for the document style.
             resources["sphinx"]["chapterstyle"] = self._prompt_chapter_title_style()
             resources["sphinx"]["outputstyle"] = self._prompt_output_style()
             
             # Small options
             resources["sphinx"]["centeroutput"] = console.prompt_boolean("Do you want to center the output? (false)", False)
             resources["sphinx"]["header"] = console.prompt_boolean("Should a Sphinx document header be used? (true)", True)
         else:
             
             # Try to use the traitlets.
             resources["sphinx"]["author"] = self.author
             resources["sphinx"]["version"] = self.version
             resources["sphinx"]["release"] = self.release
             
             # Use todays date if none is provided.
             if self.publish_date:
                 resources["sphinx"]["date"] = self.publish_date
             elif len(resources['metadata']['modified_date'].strip()) == 0:
-                resources["sphinx"]["date"] = date.today().strftime("%B %-d, %Y")
+                resources["sphinx"]["date"] = date.today().strftime(text.date_format)
             else:
                 resources["sphinx"]["date"] = resources['metadata']['modified_date']
             
             # Sphinx traitlets.
             resources["sphinx"]["chapterstyle"] = self.chapter_style
             resources["sphinx"]["outputstyle"] = self.output_style
             resources["sphinx"]["centeroutput"] = self.center_output
             resources["sphinx"]["header"] = self.use_headers
             
         # Find and pass in the path to the Sphinx dependencies.
         resources["sphinx"]["texinputs"] = os.path.realpath(os.path.join(sphinx.package_dir, "texinputs"))
         
         # Generate Pygments definitions for Latex 
         resources["sphinx"]["pygment_definitions"] = self._generate_pygments_latex_def()
         
         if not (self.overridetitle == None or len(self.overridetitle.strip()) == 0):
             resources['metadata']['name'] = self.overridetitle
         
         # End
         return nb, resources 
     
     
     def _generate_pygments_latex_def(self):
         """
         Generate the pygments latex definitions that allows pygments
         to work in latex.
         """
         
         return LatexFormatter().get_style_defs()       
     
     
     def _prompt_author(self):
         """
         Prompt the user to input an Author name
         """
         return  console.input("Author name: ")
     
     
     def _prompt_version(self):
         """
         prompt the user to enter a version number
         """
         return  console.input("Version (ie ""1.0.0""): ")
     
     
     def _prompt_release(self):
         """
         Prompt the user to input a release name
         """
         
         return  console.input("Release Name (ie ""Rough draft""): ")
     
     
     def _prompt_date(self, resources):
         """
         Prompt the user to enter a date
         """
         
         if resources['metadata']['modified_date']:
             default_date = resources['metadata']['modified_date']
         else:
-            default_date = date.today().strftime("%B %-d, %Y")
+            default_date = date.today().strftime(text.date_format)
             
         user_date = console.input("Date (deafults to \"" + default_date + "\"): ")
         if len(user_date.strip()) == 0:
             user_date = default_date
         return user_date
     
     
     def _prompt_output_style(self):
         """
         Prompts the user to pick an IPython output style.
         """
         
         # Dictionary of available output styles
         styles = {1: "simple",
                   2: "notebook"}
         
         #Append comments to the menu when displaying it to the user.
         comments = {1: "(recommended for long code segments)",
                     2: "(default)"}
         
         return console.prompt_dictionary(styles, default_style=2, menu_comments=comments)
     
     
     def _prompt_chapter_title_style(self):
         """
         Prompts the user to pick a Sphinx chapter style
         """
         
         # Dictionary of available Sphinx styles
         styles = {1: "Bjarne",
                   2: "Lenny",
                   3: "Glenn",
                   4: "Conny",
                   5: "Rejne",
                   6: "Sonny"}
         
         #Append comments to the menu when displaying it to the user.
         comments = {1: "(default)",
                     6: "(for international documents)"}
         
         return console.prompt_dictionary(styles, menu_comments=comments)
 

IPython/utils/text.py

@@ -1,713 +1,724 b''
 # encoding: utf-8
 """
 Utilities for working with strings and text.
 
 Inheritance diagram:
 
 .. inheritance-diagram:: IPython.utils.text
    :parts: 3
 """
 
 #-----------------------------------------------------------------------------
 #  Copyright (C) 2008-2011  The IPython Development Team
 #
 #  Distributed under the terms of the BSD License.  The full license is in
 #  the file COPYING, distributed as part of this software.
 #-----------------------------------------------------------------------------
 
 #-----------------------------------------------------------------------------
 # Imports
 #-----------------------------------------------------------------------------
 
 import os
 import re
+import sys
 import textwrap
 from string import Formatter
 
 from IPython.external.path import path
 from IPython.testing.skipdoctest import skip_doctest_py3, skip_doctest
 from IPython.utils import py3compat
 
 #-----------------------------------------------------------------------------
+# Declarations
+#-----------------------------------------------------------------------------
+
+# datetime.strftime date format for ipython
+if sys.platform == 'win32':
+    date_format = "%B %d, %Y"
+else:
+    date_format = "%B %-d, %Y"
+
+#-----------------------------------------------------------------------------
 # Code
 #-----------------------------------------------------------------------------
 
 class LSString(str):
     """String derivative with a special access attributes.
 
     These are normal strings, but with the special attributes:
 
         .l (or .list) : value as list (split on newlines).
         .n (or .nlstr): original value (the string itself).
         .s (or .spstr): value as whitespace-separated string.
         .p (or .paths): list of path objects
 
     Any values which require transformations are computed only once and
     cached.
 
     Such strings are very useful to efficiently interact with the shell, which
     typically only understands whitespace-separated options for commands."""
 
     def get_list(self):
         try:
             return self.__list
         except AttributeError:
             self.__list = self.split('\n')
             return self.__list
 
     l = list = property(get_list)
 
     def get_spstr(self):
         try:
             return self.__spstr
         except AttributeError:
             self.__spstr = self.replace('\n',' ')
             return self.__spstr
 
     s = spstr = property(get_spstr)
 
     def get_nlstr(self):
         return self
 
     n = nlstr = property(get_nlstr)
 
     def get_paths(self):
         try:
             return self.__paths
         except AttributeError:
             self.__paths = [path(p) for p in self.split('\n') if os.path.exists(p)]
             return self.__paths
 
     p = paths = property(get_paths)
 
 # FIXME: We need to reimplement type specific displayhook and then add this
 # back as a custom printer. This should also be moved outside utils into the
 # core.
 
 # def print_lsstring(arg):
 #     """ Prettier (non-repr-like) and more informative printer for LSString """
 #     print "LSString (.p, .n, .l, .s available). Value:"
 #     print arg
 #
 #
 # print_lsstring = result_display.when_type(LSString)(print_lsstring)
 
 
 class SList(list):
     """List derivative with a special access attributes.
 
     These are normal lists, but with the special attributes:
 
         .l (or .list) : value as list (the list itself).
         .n (or .nlstr): value as a string, joined on newlines.
         .s (or .spstr): value as a string, joined on spaces.
         .p (or .paths): list of path objects
 
     Any values which require transformations are computed only once and
     cached."""
 
     def get_list(self):
         return self
 
     l = list = property(get_list)
 
     def get_spstr(self):
         try:
             return self.__spstr
         except AttributeError:
             self.__spstr = ' '.join(self)
             return self.__spstr
 
     s = spstr = property(get_spstr)
 
     def get_nlstr(self):
         try:
             return self.__nlstr
         except AttributeError:
             self.__nlstr = '\n'.join(self)
             return self.__nlstr
 
     n = nlstr = property(get_nlstr)
 
     def get_paths(self):
         try:
             return self.__paths
         except AttributeError:
             self.__paths = [path(p) for p in self if os.path.exists(p)]
             return self.__paths
 
     p = paths = property(get_paths)
 
     def grep(self, pattern, prune = False, field = None):
         """ Return all strings matching 'pattern' (a regex or callable)
 
         This is case-insensitive. If prune is true, return all items
         NOT matching the pattern.
 
         If field is specified, the match must occur in the specified
         whitespace-separated field.
 
         Examples::
 
             a.grep( lambda x: x.startswith('C') )
             a.grep('Cha.*log', prune=1)
             a.grep('chm', field=-1)
         """
 
         def match_target(s):
             if field is None:
                 return s
             parts = s.split()
             try:
                 tgt = parts[field]
                 return tgt
             except IndexError:
                 return ""
 
         if isinstance(pattern, basestring):
             pred = lambda x : re.search(pattern, x, re.IGNORECASE)
         else:
             pred = pattern
         if not prune:
             return SList([el for el in self if pred(match_target(el))])
         else:
             return SList([el for el in self if not pred(match_target(el))])
 
     def fields(self, *fields):
         """ Collect whitespace-separated fields from string list
 
         Allows quick awk-like usage of string lists.
 
         Example data (in var a, created by 'a = !ls -l')::
             -rwxrwxrwx  1 ville None      18 Dec 14  2006 ChangeLog
             drwxrwxrwx+ 6 ville None       0 Oct 24 18:05 IPython
 
         a.fields(0) is ['-rwxrwxrwx', 'drwxrwxrwx+']
         a.fields(1,0) is ['1 -rwxrwxrwx', '6 drwxrwxrwx+']
         (note the joining by space).
         a.fields(-1) is ['ChangeLog', 'IPython']
 
         IndexErrors are ignored.
 
         Without args, fields() just split()'s the strings.
         """
         if len(fields) == 0:
             return [el.split() for el in self]
 
         res = SList()
         for el in [f.split() for f in self]:
             lineparts = []
 
             for fd in fields:
                 try:
                     lineparts.append(el[fd])
                 except IndexError:
                     pass
             if lineparts:
                 res.append(" ".join(lineparts))
 
         return res
 
     def sort(self,field= None,  nums = False):
         """ sort by specified fields (see fields())
 
         Example::
             a.sort(1, nums = True)
 
         Sorts a by second field, in numerical order (so that 21 > 3)
 
         """
 
         #decorate, sort, undecorate
         if field is not None:
             dsu = [[SList([line]).fields(field),  line] for line in self]
         else:
             dsu = [[line,  line] for line in self]
         if nums:
             for i in range(len(dsu)):
                 numstr = "".join([ch for ch in dsu[i][0] if ch.isdigit()])
                 try:
                     n = int(numstr)
                 except ValueError:
                     n = 0;
                 dsu[i][0] = n
 
 
         dsu.sort()
         return SList([t[1] for t in dsu])
 
 
 # FIXME: We need to reimplement type specific displayhook and then add this
 # back as a custom printer. This should also be moved outside utils into the
 # core.
 
 # def print_slist(arg):
 #     """ Prettier (non-repr-like) and more informative printer for SList """
 #     print "SList (.p, .n, .l, .s, .grep(), .fields(), sort() available):"
 #     if hasattr(arg,  'hideonce') and arg.hideonce:
 #         arg.hideonce = False
 #         return
 #
 #     nlprint(arg)   # This was a nested list printer, now removed.
 #
 # print_slist = result_display.when_type(SList)(print_slist)
 
 
 def indent(instr,nspaces=4, ntabs=0, flatten=False):
     """Indent a string a given number of spaces or tabstops.
 
     indent(str,nspaces=4,ntabs=0) -> indent str by ntabs+nspaces.
 
     Parameters
     ----------
 
     instr : basestring
         The string to be indented.
     nspaces : int (default: 4)
         The number of spaces to be indented.
     ntabs : int (default: 0)
         The number of tabs to be indented.
     flatten : bool (default: False)
         Whether to scrub existing indentation.  If True, all lines will be
         aligned to the same indentation.  If False, existing indentation will
         be strictly increased.
 
     Returns
     -------
 
     str|unicode : string indented by ntabs and nspaces.
 
     """
     if instr is None:
         return
     ind = '\t'*ntabs+' '*nspaces
     if flatten:
         pat = re.compile(r'^\s*', re.MULTILINE)
     else:
         pat = re.compile(r'^', re.MULTILINE)
     outstr = re.sub(pat, ind, instr)
     if outstr.endswith(os.linesep+ind):
         return outstr[:-len(ind)]
     else:
         return outstr
 
 
 def list_strings(arg):
     """Always return a list of strings, given a string or list of strings
     as input.
 
     :Examples:
 
         In [7]: list_strings('A single string')
         Out[7]: ['A single string']
 
         In [8]: list_strings(['A single string in a list'])
         Out[8]: ['A single string in a list']
 
         In [9]: list_strings(['A','list','of','strings'])
         Out[9]: ['A', 'list', 'of', 'strings']
     """
 
     if isinstance(arg,basestring): return [arg]
     else: return arg
 
 
 def marquee(txt='',width=78,mark='*'):
     """Return the input string centered in a 'marquee'.
 
     :Examples:
 
         In [16]: marquee('A test',40)
         Out[16]: '**************** A test ****************'
 
         In [17]: marquee('A test',40,'-')
         Out[17]: '---------------- A test ----------------'
 
         In [18]: marquee('A test',40,' ')
         Out[18]: '                 A test                 '
 
     """
     if not txt:
         return (mark*width)[:width]
     nmark = (width-len(txt)-2)//len(mark)//2
     if nmark < 0: nmark =0
     marks = mark*nmark
     return '%s %s %s' % (marks,txt,marks)
 
 
 ini_spaces_re = re.compile(r'^(\s+)')
 
 def num_ini_spaces(strng):
     """Return the number of initial spaces in a string"""
 
     ini_spaces = ini_spaces_re.match(strng)
     if ini_spaces:
         return ini_spaces.end()
     else:
         return 0
 
 
 def format_screen(strng):
     """Format a string for screen printing.
 
     This removes some latex-type format codes."""
     # Paragraph continue
     par_re = re.compile(r'\\$',re.MULTILINE)
     strng = par_re.sub('',strng)
     return strng
 
 
 def dedent(text):
     """Equivalent of textwrap.dedent that ignores unindented first line.
 
     This means it will still dedent strings like:
     '''foo
     is a bar
     '''
 
     For use in wrap_paragraphs.
     """
 
     if text.startswith('\n'):
         # text starts with blank line, don't ignore the first line
         return textwrap.dedent(text)
 
     # split first line
     splits = text.split('\n',1)
     if len(splits) == 1:
         # only one line
         return textwrap.dedent(text)
 
     first, rest = splits
     # dedent everything but the first line
     rest = textwrap.dedent(rest)
     return '\n'.join([first, rest])
 
 
 def wrap_paragraphs(text, ncols=80):
     """Wrap multiple paragraphs to fit a specified width.
 
     This is equivalent to textwrap.wrap, but with support for multiple
     paragraphs, as separated by empty lines.
 
     Returns
     -------
 
     list of complete paragraphs, wrapped to fill `ncols` columns.
     """
     paragraph_re = re.compile(r'\n(\s*\n)+', re.MULTILINE)
     text = dedent(text).strip()
     paragraphs = paragraph_re.split(text)[::2] # every other entry is space
     out_ps = []
     indent_re = re.compile(r'\n\s+', re.MULTILINE)
     for p in paragraphs:
         # presume indentation that survives dedent is meaningful formatting,
         # so don't fill unless text is flush.
         if indent_re.search(p) is None:
             # wrap paragraph
             p = textwrap.fill(p, ncols)
         out_ps.append(p)
     return out_ps
 
 
 def long_substr(data):
     """Return the longest common substring in a list of strings.
     
     Credit: http://stackoverflow.com/questions/2892931/longest-common-substring-from-more-than-two-strings-python
     """
     substr = ''
     if len(data) > 1 and len(data[0]) > 0:
         for i in range(len(data[0])):
             for j in range(len(data[0])-i+1):
                 if j > len(substr) and all(data[0][i:i+j] in x for x in data):
                     substr = data[0][i:i+j]
     elif len(data) == 1:
         substr = data[0]
     return substr
 
 
 def strip_email_quotes(text):
     """Strip leading email quotation characters ('>').
 
     Removes any combination of leading '>' interspersed with whitespace that
     appears *identically* in all lines of the input text.
 
     Parameters
     ----------
     text : str
 
     Examples
     --------
 
     Simple uses::
 
         In [2]: strip_email_quotes('> > text')
         Out[2]: 'text'
 
         In [3]: strip_email_quotes('> > text\\n> > more')
         Out[3]: 'text\\nmore'
 
     Note how only the common prefix that appears in all lines is stripped::
 
         In [4]: strip_email_quotes('> > text\\n> > more\\n> more...')
         Out[4]: '> text\\n> more\\nmore...'
 
     So if any line has no quote marks ('>') , then none are stripped from any
     of them ::
     
         In [5]: strip_email_quotes('> > text\\n> > more\\nlast different')
         Out[5]: '> > text\\n> > more\\nlast different'
     """
     lines = text.splitlines()
     matches = set()
     for line in lines:
         prefix = re.match(r'^(\s*>[ >]*)', line)
         if prefix:
             matches.add(prefix.group(1))
         else:
             break
     else:
         prefix = long_substr(list(matches))
         if prefix:
             strip = len(prefix)
             text = '\n'.join([ ln[strip:] for ln in lines])
     return text
 
 
 class EvalFormatter(Formatter):
     """A String Formatter that allows evaluation of simple expressions.
     
     Note that this version interprets a : as specifying a format string (as per
     standard string formatting), so if slicing is required, you must explicitly
     create a slice.
     
     This is to be used in templating cases, such as the parallel batch
     script templates, where simple arithmetic on arguments is useful.
 
     Examples
     --------
     
     In  [1]: f = EvalFormatter()
     In  [2]: f.format('{n//4}', n=8)
     Out [2]: '2'
     
     In  [3]: f.format("{greeting[slice(2,4)]}", greeting="Hello")
     Out [3]: 'll'
     """
     def get_field(self, name, args, kwargs):
         v = eval(name, kwargs)
         return v, name
 
 
 @skip_doctest_py3
 class FullEvalFormatter(Formatter):
     """A String Formatter that allows evaluation of simple expressions.
     
     Any time a format key is not found in the kwargs,
     it will be tried as an expression in the kwargs namespace.
     
     Note that this version allows slicing using [1:2], so you cannot specify
     a format string. Use :class:`EvalFormatter` to permit format strings.
     
     Examples
     --------
     
     In [1]: f = FullEvalFormatter()
     In [2]: f.format('{n//4}', n=8)
     Out[2]: u'2'
     
     In [3]: f.format('{list(range(5))[2:4]}')
     Out[3]: u'[2, 3]'
 
     In [4]: f.format('{3*2}')
     Out[4]: u'6'
     """
     # copied from Formatter._vformat with minor changes to allow eval
     # and replace the format_spec code with slicing
     def _vformat(self, format_string, args, kwargs, used_args, recursion_depth):
         if recursion_depth < 0:
             raise ValueError('Max string recursion exceeded')
         result = []
         for literal_text, field_name, format_spec, conversion in \
                 self.parse(format_string):
 
             # output the literal text
             if literal_text:
                 result.append(literal_text)
 
             # if there's a field, output it
             if field_name is not None:
                 # this is some markup, find the object and do
                 # the formatting
 
                 if format_spec:
                     # override format spec, to allow slicing:
                     field_name = ':'.join([field_name, format_spec])
 
                 # eval the contents of the field for the object
                 # to be formatted
                 obj = eval(field_name, kwargs)
 
                 # do any conversion on the resulting object
                 obj = self.convert_field(obj, conversion)
 
                 # format the object and append to the result
                 result.append(self.format_field(obj, ''))
 
         return u''.join(py3compat.cast_unicode(s) for s in result)
 
 
 @skip_doctest_py3
 class DollarFormatter(FullEvalFormatter):
     """Formatter allowing Itpl style $foo replacement, for names and attribute
     access only. Standard {foo} replacement also works, and allows full
     evaluation of its arguments.
 
     Examples
     --------
     In [1]: f = DollarFormatter()
     In [2]: f.format('{n//4}', n=8)
     Out[2]: u'2'
     
     In [3]: f.format('23 * 76 is $result', result=23*76)
     Out[3]: u'23 * 76 is 1748'
     
     In [4]: f.format('$a or {b}', a=1, b=2)
     Out[4]: u'1 or 2'
     """
     _dollar_pattern = re.compile("(.*?)\$(\$?[\w\.]+)")
     def parse(self, fmt_string):
         for literal_txt, field_name, format_spec, conversion \
                     in Formatter.parse(self, fmt_string):
             
             # Find $foo patterns in the literal text.
             continue_from = 0
             txt = ""
             for m in self._dollar_pattern.finditer(literal_txt):
                 new_txt, new_field = m.group(1,2)
                 # $$foo --> $foo
                 if new_field.startswith("$"):
                     txt += new_txt + new_field
                 else:
                     yield (txt + new_txt, new_field, "", None)
                     txt = ""
                 continue_from = m.end()
             
             # Re-yield the {foo} style pattern
             yield (txt + literal_txt[continue_from:], field_name, format_spec, conversion)
 
 #-----------------------------------------------------------------------------
 # Utils to columnize a list of string
 #-----------------------------------------------------------------------------
 
 def _chunks(l, n):
     """Yield successive n-sized chunks from l."""
     for i in xrange(0, len(l), n):
         yield l[i:i+n]
 
 
 def _find_optimal(rlist , separator_size=2 , displaywidth=80):
     """Calculate optimal info to columnize a list of string"""
     for nrow in range(1, len(rlist)+1) :
         chk = map(max,_chunks(rlist, nrow))
         sumlength = sum(chk)
         ncols = len(chk)
         if sumlength+separator_size*(ncols-1) <= displaywidth :
             break;
     return {'columns_numbers' : ncols,
             'optimal_separator_width':(displaywidth - sumlength)/(ncols-1) if (ncols -1) else 0,
             'rows_numbers' : nrow,
             'columns_width' : chk
            }
 
 
 def _get_or_default(mylist, i, default=None):
     """return list item number, or default if don't exist"""
     if i >= len(mylist):
         return default
     else :
         return mylist[i]
 
 
 @skip_doctest
 def compute_item_matrix(items, empty=None, *args, **kwargs) :
     """Returns a nested list, and info to columnize items
 
     Parameters
     ----------
 
     items :
         list of strings to columize
     empty : (default None)
         default value to fill list if needed
     separator_size : int (default=2)
         How much caracters will be used as a separation between each columns.
     displaywidth : int (default=80)
         The width of the area onto wich the columns should enter
 
     Returns
     -------
 
     Returns a tuple of (strings_matrix, dict_info)
 
     strings_matrix :
 
         nested list of string, the outer most list contains as many list as
         rows, the innermost lists have each as many element as colums. If the
         total number of elements in `items` does not equal the product of
         rows*columns, the last element of some lists are filled with `None`.
 
     dict_info :
         some info to make columnize easier:
 
         columns_numbers : number of columns
         rows_numbers    : number of rows
         columns_width   : list of with of each columns
         optimal_separator_width : best separator width between columns
 
     Examples
     --------
 
     In [1]: l = ['aaa','b','cc','d','eeeee','f','g','h','i','j','k','l']
        ...: compute_item_matrix(l,displaywidth=12)
     Out[1]:
         ([['aaa', 'f', 'k'],
         ['b', 'g', 'l'],
         ['cc', 'h', None],
         ['d', 'i', None],
         ['eeeee', 'j', None]],
         {'columns_numbers': 3,
         'columns_width': [5, 1, 1],
         'optimal_separator_width': 2,
         'rows_numbers': 5})
 
     """
     info = _find_optimal(map(len, items), *args, **kwargs)
     nrow, ncol = info['rows_numbers'], info['columns_numbers']
     return ([[ _get_or_default(items, c*nrow+i, default=empty) for c in range(ncol) ] for i in range(nrow) ], info)
 
 
 def columnize(items, separator='  ', displaywidth=80):
     """ Transform a list of strings into a single string with columns.
 
     Parameters
     ----------
     items : sequence of strings
         The strings to process.
 
     separator : str, optional [default is two spaces]
         The string that separates columns.
 
     displaywidth : int, optional [default is 80]
         Width of the display in number of characters.
 
     Returns
     -------
     The formatted string.
     """
     if not items :
         return '\n'
     matrix, info = compute_item_matrix(items, separator_size=len(separator), displaywidth=displaywidth)
     fmatrix = [filter(None, x) for x in matrix]
     sjoin = lambda x : separator.join([ y.ljust(w, ' ') for y, w in zip(x, info['columns_width'])])
     return '\n'.join(map(sjoin, fmatrix))+'\n'