Docs: update how_to_lint_and_format.md

docs/howto/how_to_lint_and_format.md

+# How to Lint and Format
+
+## Coding style
+
+- **C/C++ coding style**: Apollo adopted the
+  [Google C++ Style Guide](https://google.github.io/styleguide/cppguide.html).
+
+## Linters provided in apollo
+
+Apollo uses the following lint tools to check the code style. **Note:** As for
+now, ci will only check the style of C++ codes and it may do so in the future
+for codes in other languages.
+
+|    tool    |               file type               |          usage (from Apollo root dir)           |
+| :--------: | :-----------------------------------: | :---------------------------------------------: |
+|  cpplint   | .h .c .hpp .cpp .hh .cc .hxx .cxx .cu | ./apollo.sh lint cpp <path/to/src/dir/or/files> |
+|   flake8   |                  .py                  | ./apollo.sh lint py <path/to/src/dir/or/files>  |
+| shellcheck |           .sh .bash .bashrc           | ./apollo.sh lint sh <path/to/src/dir/or/files>  |
+
+To make sure your code conforms to the style guide, you can use command
+`bash apollo.sh lint all` to check if your code has any style problems and then
+fix them manually. Another option is to use formatters to fix style problems
+automatically.
+
+## Formatters provided in apollo
+
+Apollo integrated a set of formatting tools that cover many types of files:
+
+|     tool     |               file type               |           usage (from Apollo root dir)           | configuration file |
+| :----------: | :-----------------------------------: | :----------------------------------------------: | :----------------: |
+| clang-format | .h .c .hpp .cpp .hh .cc .hxx .cxx .cu | ./apollo.sh format -c <path/to/src/dir/or/files> |   .clang-format    |
+|   autopep8   |                  .py                  | ./apollo.sh format -p <path/to/src/dir/or/files> |      tox.ini       |
+|  buildifier  |       BUILD .BUILD .bzl .bazel        | ./apollo.sh format -b <path/to/src/dir/or/files> |         NA         |
+|    shfmt     |           .sh .bash .bashrc           | ./apollo.sh format -s <path/to/src/dir/or/files> |   .editorconfig    |
+|   prettier   |            .md .json .yaml            | ./apollo.sh format -m <path/to/src/dir/or/files> |   .prettier.json   |
+
+For ease of use, you can format all the files with types listed above using
+command `./apollo.sh format -a <path/to/src/dir/or/files>`

scripts/apollo_format.sh

@@ -33,7 +33,8 @@ function print_usage() {
   ${BLUE}-b|--bazel           ${NO_COLOR}Format Bazel code
   ${BLUE}-c|--cpp             ${NO_COLOR}Format cpp code
   ${BLUE}-s|--shell           ${NO_COLOR}Format Shell code
-  ${BLUE}-a|--all             ${NO_COLOR}Format all (C++/Python/Bazel/Shell)
+  ${BLUE}-m|--markdown        ${NO_COLOR}Format Markdown file
+  ${BLUE}-a|--all             ${NO_COLOR}Format all
   ${BLUE}-h|--help            ${NO_COLOR}Show this message"
 }
 
@@ -53,11 +54,16 @@ function run_shfmt() {
   bash "${TOP_DIR}/scripts/shfmt.sh" "$@"
 }
 
+function run_prettier() {
+  bash "${TOP_DIR}/scripts/mdfmt.sh" "$@"
+}
+
 function run_format_all() {
   run_clang_format "$@"
   run_buildifier "$@"
   run_autopep8 "$@"
   run_shfmt "$@"
+  run_prettier "$@"
 }
 
 function main() {
@@ -81,6 +87,9 @@ function main() {
     -s | --shell)
       run_shfmt "$@"
       ;;
+    -m | --markdown)
+      run_prettier "$@"
+      ;;
     -a | --all)
       run_format_all "$@"
       ;;