implementing feedback from @rossant

README.md

@@ -1,3 +1,12 @@
+---
+celltoolbar: Slideshow
+---
+
+---
+slideshow:
+  slide_type: slide
+...
+
 [![Build Status](https://travis-ci.org/rossant/ipymd.svg?branch=travis)](https://travis-ci.org/rossant/ipymd)
 [![Coverage Status](https://coveralls.io/repos/rossant/ipymd/badge.svg)](https://coveralls.io/r/rossant/ipymd)
 
@@ -45,7 +54,7 @@ with:
 
 The JSON `.ipynb` are removed from the equation, and the conversion happens on the fly. The IPython Notebook becomes an interactive Markdown text editor!
 
-A drawback is that you prompt numbers and images (for now).
+A drawback is that you lose prompt numbers and images (for now).
 
 This is useful when you write technical documents, blog posts, books, etc.
 
@@ -214,13 +223,11 @@ You can convert from any supported format to any supported format. This works by
 
 An **ipymd cell** is a Python dictionary with the following fields:
 
-* `cell_type`: `markdown` or `code`
+* `cell_type`: `markdown`, `code` or `notebok_metadata` (if implemented)
 * `input`: a string with the code input (code cell only)
 * `output`: a string with the text output and stdout (code cell only)
 * `source`: a string containing Markdown markup (markdown cell only)
 * `metadata`: a dictionary containing cell (or notebook) metadata
-* `is_notebook`: a boolean telling whether this cell's metadata is the notebook
-  metadata
 
 ### Customize the Markdown format
 
@@ -241,7 +248,8 @@ You can also implement your own format by following these instructions:
 
 * To activate this format, call this at Notebook launch time (not in a kernel!), perhaps in your `ipython_notebook_config.py`:
 
-  ```python
+```python
+
   from ipymd import format_manager
   format_manager().register(
       name='my_format',
@@ -250,26 +258,28 @@ You can also implement your own format by following these instructions:
       file_extension='.md',  # or anything else
       file_type='text',  # or JSON
   )
-  ```
+```
 
 * Now you can convert contents: `ipymd.convert(contents, from_='notebook', to='my_format')` or any other combination.
 
 ### Contributing a new ipymd format
 * To further integrate your format in ipymd, create a `ipymd/formats/my_format.py` file.
 * Put your reader and writer class in there, as well as a top-level variable:
 
-  ```python
+```python
+
   MY_FORMAT = dict(
       reader=MyFormatReader,
       writer=MyFormatWriter,
       file_extension='.md',
       file_type='text',
   )
-  ```
+```
 
 * In `setup.py`, add this to `entry_points`:
 
-  ```python
+```python
+
       ...
       entry_points={
           'ipymd.format': [
@@ -278,10 +288,10 @@ You can also implement your own format by following these instructions:
               ...
           ]
       }
-  ```
+```
 
   > Note that the `entry_point` name will be used by default. you may override
-    it, if you like, but Don't Repeat Yourself.  
+    it, if you like, but Don't Repeat Yourself.
 
 * Add some unit tests in `ipymd/formats/tests`.
 * Propose a PR!
@@ -293,25 +303,28 @@ Look at the existing format implementations for more details.
 * If you want to be able to redistribute your format without adding it to ipymd proper (i.e. in-house or experimental), implement all your code in a real python module.
 * Someplace easy to import, e.g. `myformat.py` or `myformat/__init__.py`, add:
 
-  ```python
+```python
+
   MY_FORMAT = dict(
       reader=MyFormatReader,
       writer=MyFormatWriter,
       file_extension='.md',  # or anything else
       file_type='text',  # or JSON
   )
-  ```
+```
 
   and this to your `setup.py`:
 
-  ```python
+```python
+
   ...
       entry_points={
           'ipymd.format': [
               'my_format=myformat:MY_FORMAT',
               ],
           },
   ...
-  ```
+```
+
   * Publish on pypi!
   * Your users will now be able to `pip install myformat`, then configure their Notebook to use your format with the name `my_format`.

examples/ex4.notebook.ipynb

@@ -1,4 +1,5 @@
 {
+  "nbformat": 4,
   "cells": [
     {
       "cell_type": "markdown",
@@ -66,9 +67,8 @@
       }
     }
   ],
-  "nbformat_minor": 0,
-  "nbformat": 4,
   "metadata": {
     "title": "A Slideshow"
-  }
+  },
+  "nbformat_minor": 0
 }

examples/ex4.py

@@ -1,7 +1,7 @@
 # List of ipymd cells expected for this example.
 output = [
 
-    {'is_notebook': True,
+    {'cell_type': 'notebook_metadata',
      'metadata': {'title': 'A Slideshow'}},
 
     {'cell_type': 'markdown',

ipymd/core/contents_manager.py

@@ -32,13 +32,13 @@ def _file_extension(os_path):
 class IPymdContentsManager(FileContentsManager, Configurable):
     format = Unicode('markdown', config=True)
 
-    # The name of the default kernel: if left blank, assume native (pythonX)
-    # won't store kernelspec/language_info unless forced
-    # this will be passed to the FormatManager, overwriting any config there
+    # The name of the default kernel: if left blank, assume native (pythonX),
+    # won't store kernelspec/language_info unless forced with verbose_metadata.
+    # This will be passed to the FormatManager, overwriting any config there.
     default_kernel_name = Unicode(config=True)
 
-    # don't strip any metadata
-    # this will be passed to the FormatManager, overwriting any config there
+    # Don't strip any metadata.
+    # This will be passed to the FormatManager, overwriting any config there.
     verbose_metadata = Bool(False, config=True)
 
     def __init__(self, *args, **kwargs):

ipymd/core/format_manager.py

@@ -39,16 +39,16 @@ class FormatManager(LoggingConfigurable):
     # The name of the setup_tools entry point group to use in setup.py
     entry_point_group = "ipymd.format"
 
-    # The name of the default kernel: if left blank, assume native (pythonX)
+    # The name of the default kernel: if left blank, assume native (pythonX),
     # won't store kernelspec/language_info unless forced
     # TODO: where does this get set but by the ContentsManager?
     default_kernel_name = Unicode(config=True)
 
-    # don't strip any metadata
+    # Don't strip any metadata
     # TODO: where does this get set but by the ContentsManager?
     verbose_metadata = Bool(False, config=True)
 
-    # the singleton. there can be only one.
+    # The singleton. There can be only one.
     _instance = None
 
     def __init__(self, *args, **kwargs):
@@ -254,16 +254,24 @@ def convert(self,
             # a list of ipymd cells.
             cells = contents
 
+        notebook_metadata = [cell for cell in cells
+                             if cell["cell_type"] == "notebook_metadata"]
+
         if writer is not None:
+            if notebook_metadata:
+                notebook_metadata = notebook_metadata[0]["metadata"]
+                if hasattr(writer, "write_notebook_metadata"):
+                    writer.write_notebook_metadata(notebook_metadata)
+                else:
+                    print("{} does not support notebook metadata, "
+                          "dropping metadata: {}".format(
+                              writer,
+                              notebook_metadata))
+
             # Convert from ipymd cells to the target format.
-            supports_nb_metadata = hasattr(writer, "write_notebook_metadata")
+            for cell in cells:
+                writer.write(cell)
 
-            for i, cell in enumerate(cells):
-                if cell.get("is_notebook", None) and supports_nb_metadata:
-                    writer.write_notebook_metadata(
-                        self.clean_meta(cell["metadata"]))
-                else:
-                    writer.write(cell)
             return writer.contents
         else:
             # If no writer is specified, the output is supposed to be

ipymd/formats/markdown.py

@@ -22,9 +22,6 @@
 from ..core.prompt import create_prompt
 
 
-CLOSE_NOTEBOOK_METADATA = "---"
-CLOSE_CELL_METADATA = "..."
-
 
 #------------------------------------------------------------------------------
 # Base Markdown
@@ -70,9 +67,9 @@ def _meta(self, source, is_notebook=False):
         """Turn a YAML string into ipynb cell/notebook metadata
         """
         if is_notebook:
-            return {'is_notebook': True,
+            return {'cell_type': 'notebook_metadata',
                     'metadata': source}
-        return {'is_meta': True,
+        return {'cell_type': 'cell_metadata',
                 'metadata': source}
 
     def _markdown_cell_from_regex(self, m):
@@ -96,17 +93,17 @@ def _meta_from_regex(self, m):
 
         Both must be followed by at least one blank line (\n\n).
         """
-        body = m.group("body")
-        is_notebook = m.group("sep_close") == CLOSE_NOTEBOOK_METADATA
+        body = m.group('body')
+        is_notebook = m.group('sep_close') == '---'
 
         if is_notebook:
-            # make it into a valid YAML object
-            body = body.strip()[:-3] + CLOSE_CELL_METADATA
+            # make it into a valid YAML object by stripping ---
+            body = body.strip()[:-3] + '...'
         try:
             if body:
-                return self._meta(yaml.safe_load(m.group("body")), is_notebook)
+                return self._meta(yaml.safe_load(m.group('body')), is_notebook)
             else:
-                return self._meta({"ipymd": {"empty_meta": True}}, is_notebook)
+                return self._meta({'ipymd': {'empty_meta': True}}, is_notebook)
         except Exception as err:
             raise Exception(body, err)
 
@@ -124,7 +121,7 @@ def meta(self, source, is_notebook=False):
         if source is None:
             return ''
 
-        if source.get("ipymd", {}).get("empty_meta", None):
+        if source.get('ipymd', {}).get('empty_meta', None):
             return '---\n\n'
 
         if not source:
@@ -138,7 +135,8 @@ def meta(self, source, is_notebook=False):
                                        default_flow_style=False))
 
         if is_notebook:
-            meta = meta[:-5] + "---\n\n"
+            # Replace the trailing `...\n\n`
+            meta = meta[:-5] + '---\n\n'
 
         return meta
 
@@ -181,23 +179,20 @@ class MarkdownReader(BaseMarkdownReader):
     def __init__(self, prompt=None):
         super(MarkdownReader, self).__init__()
         self._prompt = create_prompt(prompt)
+        self._notebook_metadata = {}
 
     def read(self, text, rules=None):
-        cells_and_meta = super(MarkdownReader, self).read(text, rules)
+        raw_cells = super(MarkdownReader, self).read(text, rules)
         cells = []
 
-        for i, cell_or_meta in enumerate(cells_and_meta):
-            if cell_or_meta.get("is_notebook", None):
-                if cells:
-                    raise ValueError("Notebook metadata must appear first")
-                cells.append(cell_or_meta)
-            elif (
-                cell_or_meta.get("is_meta", None) and cell_or_meta["metadata"]
-            ):
-                cells_and_meta[i + 1].update(
-                    metadata=cell_or_meta["metadata"])
+        last_index = len(raw_cells) - 1
+
+        for i, cell in enumerate(raw_cells):
+            if cell['cell_type'] == 'cell_metadata':
+                if i + 1 <= last_index:
+                    raw_cells[i + 1].update(metadata=cell['metadata'])
             else:
-                cells.append(cell_or_meta)
+                cells.append(cell)
 
         return cells
 

ipymd/formats/notebook.py

@@ -66,12 +66,14 @@ class NotebookReader(object):
 
     ignore_meta = ["collapsed", "trusted"]
 
+    def __init__(self):
+        self._notebook_metadata = {}
+
     def read(self, nb):
         assert nb['nbformat'] >= 4
-        yield {
-            "is_notebook": True,
-            "metadata": nb["metadata"]
-        }
+
+        self._notebook_metadata = nb['metadata']
+
         for cell in nb['cells']:
             ipymd_cell = {}
             metadata = self.clean_meta(cell)
@@ -88,6 +90,9 @@ def read(self, nb):
                 continue
             yield ipymd_cell
 
+    def read_notebook_metadata(self):
+        return self._notebook_metadata
+
     def clean_meta(self, cell):
         metadata = cell.get('metadata', {})
         for key in self.ignore_meta:

ipymd/formats/tests/_utils.py

@@ -56,9 +56,6 @@ def _test_reader(basename, format, ignore_notebook_meta=True):
     """Return converted and expected ipymd cells of a given example."""
     contents = _read_test_file(basename, format)
     converted = convert(contents, from_=format)
-    if ignore_notebook_meta:
-        converted = [cell for cell in converted
-                     if not cell.get("is_notebook", None)]
     expected = _exec_test_file(basename)
     return converted, expected
 

ipymd/lib/markdown.py

@@ -338,7 +338,6 @@ def parse_text(self, m):
         self.renderer.text(text)
 
     def parse_meta(self, m):
-        # raise Exception(m.groupdict())
         if not m.group("alias") and not m.group("body"):
             self.renderer.text("META SPLIT")
         elif m.group("alias") and not m.group("body"):