prettymd is a scriptable .md file pretty printer using GraalVM.
This project provides a pretty printer implemented in Java for the markdown language (.md files). Moreover, it also provides a JavaScript interface to customize the behaviour of the pretty printer (see Documentation).
GraalVM is able to build a native image out of this application. This comes in handy regarding the performance, since the native-image doesn't run on the JVM (Java Virtual Machine). This saves the overhead of the JVM, a big part of which is its startup time. Native image building happens with full ahead-of-time compilation. That means nothing is compiled during runtime and allows a fast start and runtime of the program.
The parser and visitor pattern used, derive from the Atlassian commonmark library.
- Maven (see Apache Maven)
- GraalVM (see GraalVM)
- For compilation
native-imagedepends on the local toolchain, so please make sure:glibc-devel,zlib-devel(header files for the C library andzlib) andgccare available on your system.
See the documentation on the GraalVM website how to install and use GraalVM.
Basically you have to download GraalVM and use it as your JDK instead of your normal one.
For installing maven please see Installing Apache Maven.
On Debian based distros, you can use sudo apt-get install maven to install maven on your machine.
The following examples use test.md as markdown input and example.js as JavaScript script.
Export the GraalVM temporarily as JAVA_HOME:
export JAVA_HOME=<PATH-TO-GRAALVM>
Build maven package (Hint: this will also directly build the native image. This should take around 5 minutes.):
mvn package
Pretty print a markdown file using Java:
$JAVA_HOME/bin/java -cp "target/prettymd.jar" com.pascal.prettymd.FormatPretty test.md
Pretty print a markdown file using Java and customize it with a script:
$JAVA_HOME/bin/java -cp "target/prettymd.jar" com.pascal.prettymd.FormatPretty test.md example.js
Pretty print a markdown file using the native image:
./prettymd test.md
Pretty print a markdown file using the native image and customize it with a script:
./prettymd test.md example.js
An extensive documentation of the JavaScript API can be seen at JavaScript.md.
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Because the pretty printer is implemented with a visitor pattern, there can be misbehaviour if the markdown file contains many nested items. E.g. a bold item inside a link description inside a list inside a list and so on.
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The Atlassian Commonmark parser loses the information if a heading is an alternative heading.
Header ======will become
# Header
- A presentation about this project can be found at presentation.pdf. It was held at the university of Bern in the software composition group on November 20th, 2018.
- Tested on GraalVM version: 1.0.0 RC9
- This .md file and JavaScript.md were formatted using this printer