abravalheri · September 11, 2021 14:56 · Sep 11, 2021 · Sep 11, 2021 · Sep 11, 2021 · Sep 11, 2021
diff --git a/!Dummy rst2myst example for issue.md b/!Dummy rst2myst example for issue.md
@@ -1,6 +1,6 @@
 # dummy-rst2myst-example-for-issue
 
-This repository demonstrates an issue with the [`rst2myst`](https://rst-to-myst.readthedocs.io/)
+This repository demonstrates an [issue](https://github.com/executablebooks/rst-to-myst/issues/33) with the [`rst2myst`](https://rst-to-myst.readthedocs.io/)
 conversion tool.
 
 ## Issue

diff --git a/README.md → !Dummy rst2myst example for issue.md b/README.md → !Dummy rst2myst example for issue.md
diff --git a/README.md b/README.md
@@ -3,6 +3,54 @@
 This repository demonstrates an issue with the [`rst2myst`](https://rst-to-myst.readthedocs.io/)
 conversion tool.
 
+## Issue
+
+The way `rst2myst` translates [rst substitutions](https://docutils.sourceforge.io/docs/ref/rst/restructuredtext.html#substitution-definitions) to Markdown does not seem to work properly.
+So far 2 inconsistencies have been identified:
+
+1. `rst2myst` relies on [MyST ability to use Jinja2 for substitutions](https://myst-parser.readthedocs.io/en/latest/syntax/optional.html#substitutions-with-jinja2).
+    Jinja2 requires a valid identifier (i.e., [valid Python variable names](https://docs.python.org/3/reference/lexical_analysis.html#identifiers)), which is a much more restrictive condition, and therefore not compatible with `rst` (e.g. `rst` accepts strings with spaces)
+
+2. `rst2myst` fails on translating [links with
+   substitutions](https://docutils.sourceforge.io/docs/ref/rst/restructuredtext.html#substitution-references) (e.g. `|ref|_`), which are a very common use case when writing `rst` (e.g. for creating links with bold, italic or monospaced text elements)
+
+
+This issue was first identified in
+[pyscaffold/pyscaffoldext-markdown#25](https://github.com/pyscaffold/pyscaffoldext-markdown/pull/25).
+An equivalent but minimal/simplified example can be found in [`original.rst`](./original.rst).
+
+The following command was used to convert the file to
+MyST-flavoured markdown, producing [`converted.md`](./converted.md).
+
+```bash
+$ rst2myst stream original.rst > converted.md
+```
+
+As we can see, `converted.md` contains invalid Jinja2 syntax, e.g. `{{ the
+repository service }}`, and the original *link with substitution* was converted
+to a simple link, without a substitution.
+
+
+## Expected output
+
+Two different behaviours could be expected from `rst2myst`:
+
+1. The *"rst substitution key"* could be pre-processed to produce a valid
+   Python identifier and in turn, that identifier could be used in Jinja2.
+   This include replacing or removing invalid characters, e.g. `|the repository service|`
+   could be translated to `{{ the_repository_service }}`.
+   This approach in shown in [`expected_option1.md`](./expected_option1.md)
+2. The *"rst substitution key"* could be nested inside a dict value with an
+   arbitrary name (e.g. `__`), e.g. `|the repository service|`
+   could be translated to `{{ __["the repository service"] }}`.
+   This approach in shown in [`expected_option2.md`](./expected_option2.md)
+
+Regarding *links with substitutions*, CommonMark's
+[full reference links](https://spec.commonmark.org/0.30/#full-reference-link)
+in combination with Jinja2 seem to be a good alternative, e.g.
+`|ref|_` could be translated to `[{{ ref }}][ref]`. This approach is shown in
+both `expected_option1.md` and `expected_option2.md`.
+
 ## Running the example
 
 To run this example, you will need a [Python virtual environment](https://virtualenv.pypa.io/en/latest/)
@@ -11,5 +59,16 @@ configured with the right dependencies. The following commands can be used to cr
 ```bash
 $ virtualenv -p py38 .venv
 $ source .venv/bin/activate
-$ pip install sphinx myst-parser rst-to-myst
+$ pip install sphinx myst-parser 'rst-to-myst[sphinx]'
+```
+
+(A POSIX operating system an shell is also assumed)
+
+The following commands can be used to compile the examples and serve
+HTML locally:
+
+```bash
+$ rst2myst stream original.rst > converted.md
+$ make html
+$ python3 -m http.server --directory _build/html
 ```
diff --git a/index.rst b/index.rst
@@ -6,11 +6,17 @@
 Welcome to Dummy rst2myst example for issue's documentation!
 ============================================================
 
+The purpose of this file is to setup the project in a way Sphinx process all
+example ``.rst`` and ``.md`` files.
+
 .. toctree::
    :maxdepth: 2
    :caption: Contents:
 
-
+    Original reST file <original>
+    Automatic Conversion (current state) <converted>
+    Expected Conversion (option 1) <expected_option1>
+    Expected Conversion (option 2) <expected_option2>
 
 Indices and tables
 ==================

diff --git a/converted.md b/converted.md
@@ -0,0 +1,21 @@
+---
+substitutions:
+  contribute button: '"Create pull request"'
+  the repository service: GitHub
+  virtual environments: '`virtualenv`'
+---
+
+# Automatic Conversion (current state)
+
+1. To avoid any problems with your installed Python packages, consider using [virtual environments]
+
+2. If everything works fine, push your local branch to {{ the repository service }} with:
+
+   ```
+   git push -u origin my-feature
+   ```
+
+3. Go to the web page of your fork and click {{ contribute button }} to send your changes for review.
+
+[virtual environments]: https://virtualenv.pypa.io/en/stable/
+
diff --git a/expected_option1.md b/expected_option1.md
@@ -0,0 +1,21 @@
+---
+substitutions:
+  contribute_button: '"Create pull request"'
+  the_repository_service: GitHub
+  virtual_environments: '`virtualenv`'
+---
+
+# Expected Conversion (option 1)
+
+1. To avoid any problems with your installed Python packages, consider using [{{ virtual_environments }}][virtual environments]
+
+2. If everything works fine, push your local branch to {{ the_repository_service }} with:
+
+   ```
+   git push -u origin my-feature
+   ```
+
+3. Go to the web page of your fork and click {{ contribute_button }} to send your changes for review.
+
+[virtual environments]: https://virtualenv.pypa.io/en/stable/
+
diff --git a/expected_option2.md b/expected_option2.md
@@ -0,0 +1,22 @@
+---
+substitutions:
+  "__":
+    contribute button: '"Create pull request"'
+    the repository service: GitHub
+    virtual environments: '`virtualenv`'
+---
+
+# Expected Conversion (option 2)
+
+1. To avoid any problems with your installed Python packages, consider using [{{ __["virtual environments"] }}][virtual environments]
+
+2. If everything works fine, push your local branch to {{ __["the repository service"] }} with:
+
+   ```
+   git push -u origin my-feature
+   ```
+
+3. Go to the web page of your fork and click {{ __["contribute button"] }} to send your changes for review.
+
+[virtual environments]: https://virtualenv.pypa.io/en/stable/
+
diff --git a/original.rst b/original.rst
@@ -0,0 +1,15 @@
+Original File
+=============
+
+#. To avoid any problems with your installed Python packages, consider using |virtual environments|_
+
+#. If everything works fine, push your local branch to |the repository service| with::
+
+    git push -u origin my-feature
+
+#. Go to the web page of your fork and click |contribute button| to send your changes for review.
+
+.. |virtual environments| replace:: ``virtualenv``
+.. |the repository service| replace:: GitHub
+.. |contribute button| replace:: "Create pull request"
+.. _virtual environments: https://virtualenv.pypa.io/en/stable/
diff --git a/conf.py b/conf.py
@@ -28,6 +28,19 @@
 # extensions coming with Sphinx (named 'sphinx.ext.*') or your custom
 # ones.
 extensions = [
+    "myst_parser"
+]
+
+# Configure MyST-Parser
+myst_enable_extensions = [
+    "amsmath",
+    "colon_fence",
+    "deflist",
+    "dollarmath",
+    "html_image",
+    "replacements",
+    "smartquotes",
+    "substitution",
 ]
 
 # Add any paths that contain templates here, relative to this directory.
@@ -36,7 +49,7 @@
 # List of patterns, relative to source directory, that match files and
 # directories to ignore when looking for source files.
 # This pattern also affects html_static_path and html_extra_path.
-exclude_patterns = ['_build', 'Thumbs.db', '.DS_Store']
+exclude_patterns = ['.venv', '_build', 'README.md', '!README.md', 'Thumbs.db', '.DS_Store']
 
 
 # -- Options for HTML output -------------------------------------------------

diff --git a/.gitignore b/.gitignore
@@ -0,0 +1,15 @@
+*~
+*.py[cod]
+*.orig
+*.log
+*.pot
+__pycache__/*
+.cache/*
+.*.swp
+tags
+.tox
+api/*
+_rst/*
+_build/*
+.venv*/
+.conda*/
diff --git a/Makefile b/Makefile
@@ -0,0 +1,20 @@
+# Minimal makefile for Sphinx documentation
+#
+
+# You can set these variables from the command line, and also
+# from the environment for the first two.
+SPHINXOPTS    ?=
+SPHINXBUILD   ?= sphinx-build
+SOURCEDIR     = .
+BUILDDIR      = _build
+
+# Put it first so that "make" without argument is like "make help".
+help:
+	@$(SPHINXBUILD) -M help "$(SOURCEDIR)" "$(BUILDDIR)" $(SPHINXOPTS) $(O)
+
+.PHONY: help Makefile
+
+# Catch-all target: route all unknown targets to Sphinx using the new
+# "make mode" option.  $(O) is meant as a shortcut for $(SPHINXOPTS).
+%: Makefile
+	@$(SPHINXBUILD) -M $@ "$(SOURCEDIR)" "$(BUILDDIR)" $(SPHINXOPTS) $(O)
diff --git a/README.md b/README.md
@@ -0,0 +1,15 @@
+# dummy-rst2myst-example-for-issue
+
+This repository demonstrates an issue with the [`rst2myst`](https://rst-to-myst.readthedocs.io/)
+conversion tool.
+
+## Running the example
+
+To run this example, you will need a [Python virtual environment](https://virtualenv.pypa.io/en/latest/)
+configured with the right dependencies. The following commands can be used to create one:
+
+```bash
+$ virtualenv -p py38 .venv
+$ source .venv/bin/activate
+$ pip install sphinx myst-parser rst-to-myst
+```
diff --git a/conf.py b/conf.py
@@ -0,0 +1,52 @@
+# Configuration file for the Sphinx documentation builder.
+#
+# This file only contains a selection of the most common options. For a full
+# list see the documentation:
+# http://www.sphinx-doc.org/en/master/config
+
+# -- Path setup --------------------------------------------------------------
+
+# If extensions (or modules to document with autodoc) are in another directory,
+# add these directories to sys.path here. If the directory is relative to the
+# documentation root, use os.path.abspath to make it absolute, like shown here.
+#
+# import os
+# import sys
+# sys.path.insert(0, os.path.abspath('.'))
+
+
+# -- Project information -----------------------------------------------------
+
+project = 'Dummy rst2myst example for issue'
+copyright = '2021, Anderson Bravalheri'
+author = 'Anderson Bravalheri'
+
+
+# -- General configuration ---------------------------------------------------
+
+# Add any Sphinx extension module names here, as strings. They can be
+# extensions coming with Sphinx (named 'sphinx.ext.*') or your custom
+# ones.
+extensions = [
+]
+
+# Add any paths that contain templates here, relative to this directory.
+templates_path = ['_templates']
+
+# List of patterns, relative to source directory, that match files and
+# directories to ignore when looking for source files.
+# This pattern also affects html_static_path and html_extra_path.
+exclude_patterns = ['_build', 'Thumbs.db', '.DS_Store']
+
+
+# -- Options for HTML output -------------------------------------------------
+
+# The theme to use for HTML and HTML Help pages.  See the documentation for
+# a list of builtin themes.
+#
+html_theme = 'alabaster'
+
+# Add any paths that contain custom static files (such as style sheets) here,
+# relative to this directory. They are copied after the builtin static files,
+# so a file named "default.css" will overwrite the builtin "default.css".
+html_static_path = ['_static']
diff --git a/index.rst b/index.rst
@@ -0,0 +1,20 @@
+.. Dummy rst2myst example for issue documentation master file, created by
+   sphinx-quickstart on Sat Sep 11 12:45:56 2021.
+   You can adapt this file completely to your liking, but it should at least
+   contain the root `toctree` directive.
+
+Welcome to Dummy rst2myst example for issue's documentation!
+============================================================
+
+.. toctree::
+   :maxdepth: 2
+   :caption: Contents:
+
+
+
+Indices and tables
+==================
+
+* :ref:`genindex`
+* :ref:`modindex`
+* :ref:`search`
diff --git a/make.bat b/make.bat
@@ -0,0 +1,35 @@
+@ECHO OFF
+
+pushd %~dp0
+
+REM Command file for Sphinx documentation
+
+if "%SPHINXBUILD%" == "" (
+	set SPHINXBUILD=sphinx-build
+)
+set SOURCEDIR=.
+set BUILDDIR=_build
+
+if "%1" == "" goto help
+
+%SPHINXBUILD% >NUL 2>NUL
+if errorlevel 9009 (
+	echo.
+	echo.The 'sphinx-build' command was not found. Make sure you have Sphinx
+	echo.installed, then set the SPHINXBUILD environment variable to point
+	echo.to the full path of the 'sphinx-build' executable. Alternatively you
+	echo.may add the Sphinx directory to PATH.
+	echo.
+	echo.If you don't have Sphinx installed, grab it from
+	echo.http://sphinx-doc.org/
+	exit /b 1
+)
+
+%SPHINXBUILD% -M %1 %SOURCEDIR% %BUILDDIR% %SPHINXOPTS% %O%
+goto end
+
+:help
+%SPHINXBUILD% -M help %SOURCEDIR% %BUILDDIR% %SPHINXOPTS% %O%
+
+:end
+popd