✨ NEW: Add myst_commonmark_only config option

Author: chrisjsewell

docs/develop/contributing.md

@@ -59,7 +59,7 @@ For code tests, myst-parser uses [pytest](https://docs.pytest.org)):
 You can also use [tox](https://tox.readthedocs.io), to run the tests in multiple isolated environments (see the `tox.ini` file for available test environments):
 
 ```shell
->> cd markdown-it-py
+>> cd MyST-Parser
 >> tox
 ```
 

docs/using/intro.md

@@ -80,7 +80,7 @@ Once you've enabled the `myst-parser` in Sphinx, it will be able to parse your M
 markdown documents. This means that you can use the `.md` extension for your pages,
 and write MyST markdown in these pages.
 
-:::{tip}
+:::{note}
 MyST markdown is a mixture of two flavors of markdown:
 
 It supports all the syntax of **[CommonMark Markdown](https://commonmark.org/)** at its
@@ -91,6 +91,10 @@ In addition, it includes **several extensions to CommonMark**
 designed to work with the Sphinx ecosystem (and inspired by reStructuredText)
 :::
 
+:::{tip}
+If you want to parse your files as only **strict** CommonMark (no extensions), then you can set the `conf.py` option `myst_commonmark_only=True`.
+:::
+
 The following sections cover a few core syntax patterns in MyST markdown, you can
 find a more exhaustive list in {doc}`syntax`.
 
@@ -219,6 +223,9 @@ To do so, use the keywords beginning `myst_`.
 * - Option
   - Default
   - Description
+* - `myst_commonmark_only`
+  - `False`
+  - If `True` convert text as strict CommonMark (all options below are then ignored)
 * - `myst_disable_syntax`
   - ()
   - List of markdown syntax elements to disable, see the [markdown-it parser guide](markdown_it:using).

myst_parser/main.py

@@ -28,6 +28,7 @@ class MdParserConfig:
     renderer: str = attr.ib(
         default="sphinx", validator=in_(["sphinx", "html", "docutils"])
     )
+    commonmark_only: bool = attr.ib(default=False, validator=instance_of(bool))
     dmath_enable: bool = attr.ib(default=True, validator=instance_of(bool))
     dmath_allow_labels: bool = attr.ib(default=True, validator=instance_of(bool))
     dmath_allow_space: bool = attr.ib(default=True, validator=instance_of(bool))
@@ -70,6 +71,9 @@ def default_parser(config: MdParserConfig) -> MarkdownIt:
     else:
         raise ValueError("unknown renderer type: {0}".format(config.renderer))
 
+    if config.commonmark_only:
+        return MarkdownIt("commonmark", renderer_cls=renderer_cls)
+
     md = (
         MarkdownIt("commonmark", renderer_cls=renderer_cls)
         .enable("table")