Java-- Compiler & IDE

Monorepo containing a TypeScript-based compiler/interpreter for Java-- (a simplified subset of Java), a web IDE built with Next.js + Monaco Editor, and a FastAPI backend that powers the LMS features (classes, exercises, submissions).

Architecture  |  Installation  |  Database  |  Instructions  |  Contributing

Architecture

The project is split into three independent packages:

Package	Stack	Purpose
packages/compiler	TypeScript, Vitest	Lexer, parser, IR generator, and interpreter for Java--
packages/ide	Next.js 16, React 19, Monaco, Tailwind v4	Web IDE with editor, terminal, token analysis, and LMS UI
backend	FastAPI, SQLAlchemy (async), Alembic, PostgreSQL	REST API for auth, classes, exercises, submissions

Compiler pipeline

input-code.java → Lexer → Token[] → TokenIterator → Parser (+ IR Emitter) → Instruction[] → Interpreter → Output

• Lexer: character-by-character scanning via a factory of specialized scanners (comments, identifiers, numbers, strings, operators).
• Parser: recursive-descent — one file per grammar production under packages/compiler/src/grammar/syntax/.
• IR: three-address code with temporary variables (__temp0, __temp1, ...) and labels for control flow.
• Interpreter: executes the IR using a symbol table, label table, and instruction pointer. I/O is abstracted via injectable stdout/stdin callbacks.

Installation

Compiler

cd packages/compiler
npm install && npm run start   # runs against src/resource/input-code.java
npm run test                   # Vitest

IDE

cd packages/ide
npm install && npm run dev     # http://localhost:3001

The IDE consumes the compiler as a local workspace dependency (@ts-compilator-for-java/compiler).

Backend (FastAPI)

cd backend
uv sync
uv run alembic upgrade head    # apply DB migrations
uv run uvicorn app.main:app --reload

Or run the full stack with Docker:

docker-compose up

Database

PostgreSQL schema for the LMS layer (organizations, classes, exercises, submissions). Migrations are managed by Alembic — see backend/migrations/.

erDiagram
    organizations ||--o{ users : "has"
    organizations ||--o{ classes : "has"

    users ||--o{ exercises : "creates (teacher)"
    users ||--o{ exercise_lists : "creates (teacher)"
    users ||--o{ classes : "teaches"
    users ||--o{ class_members : "enrolled (student)"
    users ||--o{ submissions : "submits (student)"

    exercises ||--o{ test_cases : "contains"
    exercises ||--o{ exercise_list_items : "part of"
    exercises ||--o{ submissions : "receives"

    exercise_lists ||--o{ exercise_list_items : "groups"
    exercise_lists ||--o{ class_exercise_lists : "published in"
    exercise_lists ||--o{ submissions : "scope of"

    classes ||--o{ class_members : "has members"
    classes ||--o{ class_exercise_lists : "receives lists"
    classes ||--o{ submissions : "context of"

    organizations {
        serial id PK
        varchar name
        timestamp created_at
    }

    users {
        serial id PK
        integer organization_id FK
        userrole role
        varchar email UK
        varchar password
        varchar name
        varchar avatar_url
        varchar bio
    }

    exercises {
        serial id PK
        integer teacher_id FK
        varchar title
        varchar description
        varchar attachments
        timestamp created_at
        timestamp updated_at
    }

    test_cases {
        serial id PK
        integer exercise_id FK
        varchar label
        varchar input
        varchar expected_output
        integer order_index
    }

    exercise_lists {
        serial id PK
        integer teacher_id FK
        varchar title
        varchar description
        timestamp created_at
        timestamp updated_at
    }

    exercise_list_items {
        integer exercise_list_id PK,FK
        integer exercise_id PK,FK
        double grade_weight
        integer order_index
    }

    classes {
        serial id PK
        integer organization_id FK
        integer teacher_id FK
        varchar name
        varchar description
        varchar access_code UK
        timestamp created_at
        classstatus status
    }

    class_members {
        integer class_id PK,FK
        integer student_id PK,FK
        timestamp joined_at
    }

    class_exercise_lists {
        integer exercise_list_id PK,FK
        integer class_id PK,FK
        timestamp deadline
        double total_grade
        integer min_required
        timestamp published_at
        timestamp updated_at
    }

    submissions {
        serial id PK
        integer exercise_id FK
        integer exercise_list_id FK
        integer class_id FK
        integer student_id FK
        varchar code_snapshot
        submissionstatus status
        double score
        varchar teacher_feedback
        timestamp submitted_at
    }

Loading

Reference files:

• Raw SQL dump: tcc/victor/db.sql
• DBML (dbdiagram.io): tcc/victor/dbdocs.txt
• Extended diagram with legends: tcc/victor/db-diagram.md

Instructions

Each package has its own README with implementation details:

• Compiler README
• IDE README
• Backend README

To test the compiler with custom code, edit packages/compiler/src/resource/input-code.java and run npm run start.

The compiler entry point is packages/compiler/src/index.ts.

Original specification (PDF)

Repository Layout

.
├── backend/            # FastAPI + SQLAlchemy + Alembic
├── packages/
│   ├── compiler/       # Lexer, parser, IR, interpreter
│   └── ide/            # Next.js IDE
├── tcc/                # Undergraduate thesis (LaTeX)
│   ├── igor/
│   └── victor/         # Includes db.sql, dbdocs.txt, db-diagram.md
├── docs/
├── qualificacao/       # Qualification documents
├── CLAUDE.md           # Project guidance for Claude Code
├── DESIGN.md           # Design decisions
└── docker-compose.yml

Contributing

Contributions are welcome — especially new test cases and language feature suggestions. Open an issue or PR.

Authors

• Igor Lamoia
• Victor Souza