export_format is an enum

and options are included in help output

examples expanded

IPython/nbconvert/nbconvertapp.py

@@ -1,200 +1,218 b''
 #!/usr/bin/env python
 """NBConvert is a utility for conversion of .ipynb files.
 
 Command-line interface for the NbConvert conversion utility.
 """
 #-----------------------------------------------------------------------------
 #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
 #-----------------------------------------------------------------------------
 
 #Stdlib imports
 from __future__ import print_function
 import sys
 import os
 import glob
 
 #From IPython
 from IPython.core.application import BaseIPythonApplication, base_aliases, base_flags
 from IPython.config import catch_config_error, Configurable
-from IPython.utils.traitlets import Unicode, List, Instance, DottedObjectName, Type
+from IPython.utils.traitlets import (
+    Unicode, List, Instance, DottedObjectName, Type, CaselessStrEnum,
+)
 from IPython.utils.importstring import import_item
 
 from .exporters.export import export_by_name, get_export_names, ExporterNameError
 from IPython.nbconvert import exporters, transformers, writers
 from .utils.base import NbConvertBase
 
 #-----------------------------------------------------------------------------
 #Classes and functions
 #-----------------------------------------------------------------------------
 
 nbconvert_aliases = {}
 nbconvert_aliases.update(base_aliases)
 nbconvert_aliases.update({
     'format' : 'NbConvertApp.export_format',
     'notebooks' : 'NbConvertApp.notebooks',
     'writer' : 'NbConvertApp.writer_class',
 })
 
 nbconvert_flags = {}
 nbconvert_flags.update(base_flags)
 nbconvert_flags.update({
     'stdout' : (
         {'NbConvertApp' : {'writer_class' : "StdoutWriter"}},
         "Write notebook output to stdout instead of files."
         )
 })
 
 
 class NbConvertApp(BaseIPythonApplication):
     """Application used to convert to and from notebook file type (*.ipynb)"""
 
     name = 'ipython-nbconvert'
     aliases = nbconvert_aliases
     flags = nbconvert_flags
     
     def _classes_default(self):
         classes = [NbConvertBase]
         for pkg in (exporters, transformers, writers):
             for name in dir(pkg):
                 cls = getattr(pkg, name)
                 if isinstance(cls, type) and issubclass(cls, Configurable):
                     classes.append(cls)
         return classes
 
     description = Unicode(
-        u"""This application is used to convert notebook files (*.ipynb).
-        An ipython config file can be used to batch convert notebooks in the 
-        current directory.""")
+        u"""This application is used to convert notebook files (*.ipynb)
+        to various other formats.""")
 
     examples = Unicode(u"""
+        The simplest way to use nbconvert is
+        
+        > ipython nbconvert mynotebook.ipynb
+        
+        which will convert mynotebook.ipynb to the default format (probably HTML).
+        
+        You can specify the export format with `--format`.
+        Options include {0}
+        
+        > ipython nbconvert --format latex mynotebook.ipnynb
+        
+        You can also pipe the output to stdout, rather than a file
+        
+        > ipython nbconvert mynotebook.ipynb --stdout
+        
         Multiple notebooks can be given at the command line in a couple of 
         different ways:
   
         > ipython nbconvert notebook*.ipynb
         > ipython nbconvert notebook1.ipynb notebook2.ipynb
-        > ipython nbconvert --format sphinx_howto notebook.ipynb
-        """)
+        """.format(get_export_names()))
     #Writer specific variables
     writer = Instance('IPython.nbconvert.writers.base.WriterBase',  
                       help="""Instance of the writer class used to write the 
                       results of the conversion.""")
     writer_class = DottedObjectName('FilesWriter', config=True, 
                                     help="""Writer class used to write the 
                                     results of the conversion""")
     writer_aliases = {'FilesWriter': 'IPython.nbconvert.writers.files.FilesWriter',
                       'DebugWriter': 'IPython.nbconvert.writers.debug.DebugWriter',
                       'StdoutWriter': 'IPython.nbconvert.writers.stdout.StdoutWriter'}
     writer_factory = Type()
 
     def _writer_class_changed(self, name, old, new):
         if new in self.writer_aliases:
             new = self.writer_aliases[new]
         self.writer_factory = import_item(new)
 
 
     #Other configurable variables
-    export_format = Unicode(
-        "full_html", config=True,
-        help="""If specified, nbconvert will convert the document(s) specified
-                using this format.""")
+    export_format = CaselessStrEnum(get_export_names(),
+        default_value="full_html",
+        config=True,
+        help="""The export format to be used."""
+    )
 
     notebooks = List([], config=True, help="""List of notebooks to convert.
-                     Search patterns are supported.""")
+                     Wildcards are supported.
+                     Filenames passed positionally will be added to the list.
+                     """)
 
     @catch_config_error
     def initialize(self, argv=None):
         super(NbConvertApp, self).initialize(argv)
         self.init_notebooks()
         self.init_writer()
 
     def init_notebooks(self):
         """
         Add notebooks to the config if needed.  Glob each notebook to replace
         notebook patterns with filenames.
         """
 
         #Get any additional notebook patterns from the commandline
         patterns = self.notebooks + self.extra_args
 
         #Use glob to replace all the notebook patterns with filenames.
         filenames = []
         for pattern in patterns:
             for filename in glob.glob(pattern):
                 if not filename in filenames:
                     filenames.append(filename)
         self.notebooks = filenames
 
     def init_writer(self):
         """
         Initialize the writer (which is stateless)
         """
         self._writer_class_changed(None, self.writer_class, self.writer_class)
         self.writer = self.writer_factory(parent=self)
 
     def start(self):
         """
         Ran after initialization completed
         """
         super(NbConvertApp, self).start()
         self.convert_notebooks()
 
     def convert_notebooks(self):
         """
         Convert the notebooks in the self.notebook traitlet
         """
         #Export each notebook
         conversion_success = 0
         for notebook_filename in self.notebooks:
 
             #Get a unique key for the notebook and set it in the resources object.
             basename = os.path.basename(notebook_filename)
             notebook_name = basename[:basename.rfind('.')]
             resources = {}
             resources['unique_key'] = notebook_name
 
             #Try to export
             try:
                 output, resources = export_by_name(self.export_format,
                                               notebook_filename, 
                                               resources=resources,
                                               config=self.config)
             except ExporterNameError as e:
                 print("Error: '%s' exporter not found." % self.export_format,
                       file=sys.stderr)
                 print("Known exporters are:",
                       "\n\t" + "\n\t".join(get_export_names()),
                       file=sys.stderr)
                 sys.exit(-1)
             #except Exception as e:
                 #print("Error: could not export '%s'" % notebook_filename, file=sys.stderr)
                 #print(e, file=sys.stderr)
             else:
                 self.writer.write(output, resources, notebook_name=notebook_name)
                 conversion_success += 1
 
         #If nothing was converted successfully, help the user.
         if conversion_success == 0:
 
             #No notebooks were specified, show help.
             if len(self.notebooks) == 0:
                 self.print_help()
 
             #Notebooks were specified, but not converted successfully.  Show how
             #to access help.
             else:
                 print('For help, use "ipython nbconvert --help"')
 
 
 #-----------------------------------------------------------------------------
 # Main entry point
 #-----------------------------------------------------------------------------
 
 launch_new_instance = NbConvertApp.launch_instance