LipVM

Import the project

Step 1: create a Python virtual environment

python3 -m venv .venv

Step 2: activate the virtual environment

On Unix systems:

source .venv/bin/activate

On Windows:

.venv\Scripts\activate

Generate parser and visitor for a language

Requirements:

• An ANTLR4 grammar file, e.g. src/languages/Minilogo/syntax/Language.g4.
  • For now the grammar must be named: Language.
  • The root parsing rule must be named start.
• A Java installation, version 21 or superior.
• The antlr-4.13.2-complete.jar from https://www.antlr.org/download.html.

java -jar antlr-4.13.2-complete.jar -Dlanguage=Python3 src/languages/Minilogo/syntax/Language.g4 -no-listener -visitor

Upon the execution of this command, an AST visitor is generated: see src/languages/Minilogo/syntax/LanguageVisitor.py.

Specify the semantic of a language

Based on the generated visitor, create a Compiler class in the directory of your language: see src/languages/Minilogo/Compiler.py.

This class is expected to implement a def compile(self, code) method returning an instance of Bytecode (see at the root of the project).

This instance of Bytecode should hold a list of instructions to execute.
It is the responsibility of the language implementor to define these instructions.
To create one language instruction, create a class that implements the def execute(self, stack, global_variables, heap).
This method defines the behavior of each of the language instruction. The method parameters represent:

• stack: the underlying interpreter stack (instance of Stack)
• global_variables: the global variables of the program
• heap: the long term memory space

Try Minilogo

To start the currently implemented LipVM with Minilogo, execute the following command:

python -m src.languages.minilogo.ide.Minilogo

Debug

To debug, for now I use debugpy using the following command taking file.logo (a logo code file) in argument:

python -m debugpy --wait-for-client --listen 5678 LipVM.py file.logo

Using VSCode you can use the following launch.json configuration to connect to the debugging session:

{
  "version": "0.2.0",
  "configurations": [
      {
          "name": "Python Debugger: Remote Attach",
          "type": "debugpy",
          "request": "attach",
          "connect": {
              "host": "localhost",
              "port": 5678
          }
      }
  ]
}