Setup

libtree-sitter

macOS and Linux

1. cd into tree-sitter/ and run make -j to create the shared library

Windows

1. (on Windows, run the following commands):

   # Set environment variables
   export CC=clang
   export WASM=OFF
   
   # Build the shared library
   cmake -S lib -B build/shared \
          -DBUILD_SHARED_LIBS=ON \
          -DCMAKE_BUILD_TYPE=Debug \
          -DCMAKE_COMPILE_WARNING_AS_ERROR=ON \
          -DTREE_SITTER_FEATURE_WASM=$WASM
    cmake --build build/shared --verbose

2. The file is in build/share. Rename it without the versions, e.g. libtree-sitter.dll.

Note

Now, you should have a shared library in the root, under the name of libtree-sitter with an extension of .so, .dylib or .dll.

This is the library powering the parsing of the text. By binding it to Java, we can call native functions (machine code) from a higher-level API. This library is in charge of reading the incoming text and parse it into tokens.

Grammar

1. Install tree-sitter CLI from here (tested using 0.24.3).
2. cd into tree-sitter-simpl/ and run

   tree-sitter generate
   tree-sitter build

   To generate and build the grammar. This will output another shared library, and should have the same extension as libtree-sitter.

Note

While libtree-sitter parses the file into tokens, it doesn't know how to, because different programming languages provides different arrangements of the tokens. A piece of text that is valid in one language might not be in the other, or interpreted in different ways. Take the following code:

fn foo() -> number {
  return 1;
}

It can produce valid tokens for both rust and simpl, yet their structure would be different. This is because the libtree-sitter parses the input code and creates the syntax tree, while the grammar defines the rules for a specific language.

3. Since the Java program only looks for simpl.dylib, you can rename the file extension to .dylib. If that doesn't work, you can go into src/main/java/net/borui/simpl/Main.java, search for ./tree-sitter-simpl/simpl.dylib, and change that to the same extension as on libtree-sitter.

Compiling the Interpreter

1. Install maven
2. There are two ways to proceed:
   • Run ./test.sh
   • Or this two-step process:
     1. Run maven package once to compile
     2. Run java -cp target/simpl-1.0-SNAPSHOT-jar-with-dependencies.jar --enable-native-access=ALL-UNNAMED net.borui.simpl.Main.