Automatic markdown and YAML formatting with Prettier (#874)

.appveyor.yml

@@ -1,26 +1,26 @@
 install:
-- C:\Python36\python.exe -m pip install mypy
-- C:\Python36\python.exe -m pip install -e .[d]
+  - C:\Python36\python.exe -m pip install mypy
+  - C:\Python36\python.exe -m pip install -e .[d]
 
 # Not a C# project
 build: off
 
 test_script:
-- C:\Python36\python.exe tests/test_black.py
-- C:\Python36\python.exe -m mypy black.py blackd.py tests/test_black.py
+  - C:\Python36\python.exe tests/test_black.py
+  - C:\Python36\python.exe -m mypy black.py blackd.py tests/test_black.py
 
 after_test:
   - C:\Python36\python.exe -m pip install pyinstaller
-  - "%CMD_IN_ENV% C:\\Python36\\python.exe -m PyInstaller --clean -F --add-data blib2to3/;blib2to3 black.py"
+  - "%CMD_IN_ENV% C:\\Python36\\python.exe -m PyInstaller --clean -F --add-data
+    blib2to3/;blib2to3 black.py"
 
 artifacts:
   - path: dist/black.exe
 
 deploy:
   provider: GitHub
-  description: ''
+  description: ""
   auth_token:
     secure: uplI9CJ2dTGcEBCbZuIn+Qb4rC38hOoRSH9lcwuGCr5g9fSnhK1MZdNT6Cjf/mFL
   on:
     APPVEYOR_REPO_TAG: true
-

.github/CODE_OF_CONDUCT.md

@@ -1,13 +1,11 @@
 # Treat each other well
 
-Everyone participating in the *Black* project, and in particular in the
-issue tracker, pull requests, and social media activity, is expected
-to treat other people with respect and more generally to follow the
-guidelines articulated in the [Python Community Code of
-Conduct](https://www.python.org/psf/codeofconduct/).
+Everyone participating in the _Black_ project, and in particular in the issue tracker,
+pull requests, and social media activity, is expected to treat other people with respect
+and more generally to follow the guidelines articulated in the
+[Python Community Code of Conduct](https://www.python.org/psf/codeofconduct/).
 
-At the same time, humor is encouraged.  In fact, basic familiarity with
-Monty Python's Flying Circus is expected.  We are not savages.
+At the same time, humor is encouraged. In fact, basic familiarity with Monty Python's
+Flying Circus is expected. We are not savages.
 
-And if you *really* need to slap somebody, do it with a fish while
-dancing.
+And if you _really_ need to slap somebody, do it with a fish while dancing.

.github/ISSUE_TEMPLATE/bug_report.md

@@ -1,37 +1,35 @@
 ---
 name: Bug report
 about: Create a report to help us improve
-title: ''
+title: ""
 labels: bug
-assignees: ''
-
+assignees: ""
 ---
 
-**Describe the bug**
-A clear and concise description of what the bug is.
+**Describe the bug** A clear and concise description of what the bug is.
+
+**To Reproduce** Steps to reproduce the behavior:
 
-**To Reproduce**
-Steps to reproduce the behavior:
 1. Take this file '...'
-2. Run *Black* on it with these arguments '....'
+2. Run _Black_ on it with these arguments '....'
 3. See error
 
-**Expected behavior**
-A clear and concise description of what you expected to happen.
+**Expected behavior** A clear and concise description of what you expected to happen.
 
 **Environment (please complete the following information):**
+
 - Version: [e.g. master]
 - OS and Python version: [e.g. Linux/Python 3.7.4rc1]
 
-**Does this bug also happen on master?**
-To answer this, you have two options:
-1. Use the online formatter at https://black.now.sh/?version=master, which will use the latest master branch.
-2. Or run *Black* on your machine:
-    * create a new virtualenv (make sure it's the same Python version);
-    * clone this repository;
-    * run `pip install -e .`;
-    * make sure it's sane by running `python setup.py test`; and
-    * run `black` like you did last time.
+**Does this bug also happen on master?** To answer this, you have two options:
 
-**Additional context**
-Add any other context about the problem here.
+1. Use the online formatter at https://black.now.sh/?version=master, which will use the
+   latest master branch.
+2. Or run _Black_ on your machine:
+   - create a new virtualenv (make sure it's the same Python version);
+   - clone this repository;
+   - run `pip install -e .`;
+   - make sure it's sane by running `python setup.py test`; and
+   - run `black` like you did last time.
+
+**Additional context** Add any other context about the problem here.

.github/ISSUE_TEMPLATE/feature_request.md

@@ -1,20 +1,19 @@
 ---
 name: Feature request
 about: Suggest an idea for this project
-title: ''
+title: ""
 labels: enhancement
-assignees: ''
-
+assignees: ""
 ---
 
-**Is your feature request related to a problem? Please describe.**
-A clear and concise description of what the problem is. Ex. I'm always frustrated when [...]
+**Is your feature request related to a problem? Please describe.** A clear and concise
+description of what the problem is. Ex. I'm always frustrated when [...]
 
-**Describe the solution you'd like**
-A clear and concise description of what you want to happen.
+**Describe the solution you'd like** A clear and concise description of what you want to
+happen.
 
-**Describe alternatives you've considered**
-A clear and concise description of any alternative solutions or features you've considered.
+**Describe alternatives you've considered** A clear and concise description of any
+alternative solutions or features you've considered.
 
-**Additional context**
-Add any other context or screenshots about the feature request here.
+**Additional context** Add any other context or screenshots about the feature request
+here.

.github/ISSUE_TEMPLATE/style_issue.md

@@ -1,30 +1,29 @@
 ---
 name: Style issue
 about: Help us improve the Black style
-title: ''
+title: ""
 labels: design
-assignees: ''
-
+assignees: ""
 ---
 
-**Describe the style change**
-A clear and concise description of how the style can be improved.
+**Describe the style change** A clear and concise description of how the style can be
+improved.
+
+**Examples in the current _Black_ style** Think of some short code snippets that show
+how the current _Black_ style is not great:
 
-**Examples in the current *Black* style**
-Think of some short code snippets that show how the current *Black* style is not great:
 ```
 def f():
     "Make sure this code is blackened"""
     pass
 ```
 
-**Desired style**
-How do you think *Black* should format the above snippets:
+**Desired style** How do you think _Black_ should format the above snippets:
+
 ```
 def f(
     ):
     pass
 ```
 
-**Additional context**
-Add any other context about the problem here.
+**Additional context** Add any other context about the problem here.

.pre-commit-config.yaml

@@ -22,3 +22,9 @@ repos:
     hooks:
       - id: mypy
         exclude: ^docs/conf.py
+
+  - repo: https://github.com/prettier/prettier
+    rev: 1.18.2
+    hooks:
+      - id: prettier
+        args: [--prose-wrap=always, --print-width=88]

.pre-commit-hooks.yaml

@@ -1,8 +1,8 @@
--   id: black
-    name: black
-    description: 'Black: The uncompromising Python code formatter'
-    entry: black
-    language: python
-    language_version: python3
-    require_serial: true
-    types: [python]
+- id: black
+  name: black
+  description: "Black: The uncompromising Python code formatter"
+  entry: black
+  language: python
+  language_version: python3
+  require_serial: true
+  types: [python]

.travis.yml

@@ -4,14 +4,14 @@ cache:
   directories:
     - $HOME/.cache/pre-commit
 env:
-- TEST_CMD="coverage run tests/test_black.py"
+  - TEST_CMD="coverage run tests/test_black.py"
 install:
-- pip install coverage coveralls pre-commit
-- pip install -e '.[d]'
+  - pip install coverage coveralls pre-commit
+  - pip install -e '.[d]'
 script:
-- $TEST_CMD
+  - $TEST_CMD
 after_success:
-- coveralls
+  - coveralls
 notifications:
   on_success: change
   on_failure: always

CONTRIBUTING.md

@@ -1,61 +1,54 @@
-# Contributing to *Black*
-
-Welcome! Happy to see you willing to make the project better. Have you
-read the entire [user documentation](https://black.readthedocs.io/en/latest/)
-yet?
+# Contributing to _Black_
 
+Welcome! Happy to see you willing to make the project better. Have you read the entire
+[user documentation](https://black.readthedocs.io/en/latest/) yet?
 
 ## Bird's eye view
 
-In terms of inspiration, *Black* is about as configurable as *gofmt*.
-This is deliberate.
+In terms of inspiration, _Black_ is about as configurable as _gofmt_. This is
+deliberate.
 
-Bug reports and fixes are always welcome!  Please follow the [issue
-template on GitHub](https://github.com/psf/black/issues/new) for best 
-results.
-
-Before you suggest a new feature or configuration knob, ask yourself why
-you want it.  If it enables better integration with some workflow, fixes
-an inconsistency, speeds things up, and so on - go for it!  On the other
-hand, if your answer is "because I don't like a particular formatting"
-then you're not ready to embrace *Black* yet. Such changes are unlikely
-to get accepted. You can still try but prepare to be disappointed.
+Bug reports and fixes are always welcome! Please follow the
+[issue template on GitHub](https://github.com/psf/black/issues/new) for best results.
 
+Before you suggest a new feature or configuration knob, ask yourself why you want it. If
+it enables better integration with some workflow, fixes an inconsistency, speeds things
+up, and so on - go for it! On the other hand, if your answer is "because I don't like a
+particular formatting" then you're not ready to embrace _Black_ yet. Such changes are
+unlikely to get accepted. You can still try but prepare to be disappointed.
 
 ## Technicalities
 
-Development on the latest version of Python is preferred.  As of this
-writing it's 3.8. You can use any operating system.  I am using macOS
-myself and CentOS at work.
+Development on the latest version of Python is preferred. As of this writing it's 3.8.
+You can use any operating system. I am using macOS myself and CentOS at work.
 
 Install all development dependencies using:
+
 ```
 $ pipenv install --dev
 $ pipenv shell
 $ pre-commit install
 ```
-If you haven't used `pipenv` before but are comfortable with virtualenvs,
-just run `pip install pipenv` in the virtualenv you're already using and
-invoke the command above from the cloned *Black* repo. It will do the
-correct thing.
+
+If you haven't used `pipenv` before but are comfortable with virtualenvs, just run
+`pip install pipenv` in the virtualenv you're already using and invoke the command above
+from the cloned _Black_ repo. It will do the correct thing.
 
 Before submitting pull requests, run tests with:
+
 ```
 $ python setup.py test
 ```
 
-
 ## Hygiene
 
-If you're fixing a bug, add a test.  Run it first to confirm it fails,
-then fix the bug, run it again to confirm it's really fixed.
-
-If adding a new feature, add a test.  In fact, always add a test.  But
-wait, before adding any large feature, first open an issue for us to
-discuss the idea first.
+If you're fixing a bug, add a test. Run it first to confirm it fails, then fix the bug,
+run it again to confirm it's really fixed.
 
+If adding a new feature, add a test. In fact, always add a test. But wait, before adding
+any large feature, first open an issue for us to discuss the idea first.
 
 ## Finally
 
-Thanks again for your interest in improving the project!  You're taking
-action when most people decide to sit and watch.
+Thanks again for your interest in improving the project! You're taking action when most
+people decide to sit and watch.

docs/environment.yml

@@ -2,9 +2,9 @@ name: black_docs
 channels:
   - conda-forge
 dependencies:
-- python>=3.6
-- Sphinx==1.7.2
-- pip:
-  - recommonmark==0.4.0
-  - git+https://git@github.com/psf/black.git
-  - setuptools_scm==3.3.3
+  - python>=3.6
+  - Sphinx==1.7.2
+  - pip:
+      - recommonmark==0.4.0
+      - git+https://git@github.com/psf/black.git
+      - setuptools_scm==3.3.3

readthedocs.yml

@@ -1,6 +1,6 @@
 name: black
 type: sphinx
 conda:
-    file: docs/environment.yml
+  file: docs/environment.yml
 python:
   version: 3