Add mystnb format

.travis.yml

@@ -39,7 +39,7 @@ install:
       pip install -r requirements.txt;
     fi
   # install is required for testing the pre-commit mode
-  - pip install . || true
+  - pip install .[myst] || true
   # install black if available (Python 3.6 and above), and autopep8 for testing the pipe mode
   - pip install black || true
   - pip install autopep8 || true

environment.yml

@@ -22,3 +22,4 @@ dependencies:
   - setuptools
   - twine
   - pandoc
+  - myst-parser

jupytext/formats.py

@@ -19,6 +19,12 @@
 from .languages import _SCRIPT_EXTENSIONS, _COMMENT_CHARS, same_language
 from .pandoc import pandoc_version, is_pandoc_available
 from .magics import is_magic
+from .myst import (
+    MYST_FORMAT_NAME,
+    is_myst_available,
+    myst_version,
+    myst_extensions,
+)
 
 
 class JupytextFormatError(ValueError):
@@ -162,6 +168,15 @@ def __init__(self,
         cell_exporter_class=None,
         current_version_number=pandoc_version()))
 
+if is_myst_available():
+    JUPYTEXT_FORMATS.extend([NotebookFormatDescription(
+        format_name=MYST_FORMAT_NAME,
+        extension=ext,
+        header_prefix='',
+        cell_reader_class=None,
+        cell_exporter_class=None,
+        current_version_number=myst_version()) for ext in myst_extensions()])
+
 NOTEBOOK_EXTENSIONS = list(dict.fromkeys(['.ipynb'] + [fmt.extension for fmt in JUPYTEXT_FORMATS]))
 EXTENSION_PREFIXES = ['.lgt', '.spx', '.pct', '.hyd', '.nb']
 

jupytext/jupytext.py

@@ -19,6 +19,7 @@
 from .languages import default_language_from_metadata_and_ext, set_main_and_cell_language
 from .pep8 import pep8_lines_between_cells
 from .pandoc import md_to_notebook, notebook_to_md
+from .myst import myst_extensions, myst_to_notebook, notebook_to_myst
 
 
 class TextNotebookConverter(NotebookReader, NotebookWriter):
@@ -54,6 +55,9 @@ def reads(self, s, **_):
         if self.fmt.get('format_name') == 'pandoc':
             return md_to_notebook(s)
 
+        if self.ext in myst_extensions():
+            return myst_to_notebook(s)
+
         lines = s.splitlines()
 
         cells = []
@@ -123,6 +127,26 @@ def writes(self, nb, metadata=None, **kwargs):
                 metadata=metadata,
                 cells=cells))
 
+        if self.ext in myst_extensions():
+            pygments_lexer = metadata.get("language_info", {}).get("pygments_lexer", None)
+            metadata = insert_jupytext_info_and_filter_metadata(metadata, self.ext, self.implementation)
+
+            cells = []
+            for cell in nb.cells:
+                cell_metadata = filter_metadata(cell.metadata,
+                                                self.fmt.get('cell_metadata_filter'),
+                                                _IGNORE_CELL_METADATA)
+                if cell.cell_type == 'code':
+                    cells.append(new_code_cell(source=cell.source, metadata=cell_metadata))
+                else:
+                    cells.append(NotebookNode(source=cell.source, metadata=cell_metadata, cell_type=cell.cell_type))
+            return notebook_to_myst(NotebookNode(
+                nbformat=nb.nbformat,
+                nbformat_minor=nb.nbformat_minor,
+                metadata=metadata,
+                cells=cells),
+                default_lexer=pygments_lexer)
+
         # Copy the notebook, in order to be sure we do not modify the original notebook
         nb = NotebookNode(
             nbformat=nb.nbformat,