plijava

Conversion of PL/I code into similar Java code. It is a fork of my plithon PL/I to Python project.

Important: this work is primarily the intermediate result of a learning process. It is not intended to be the full realisation of the work shown in the title. It contains errors which I am trying to correct. It is not complete, but will be expanded.

plijava is a lightweight PL/I → Java transpiler and runtime helper. It parses a subset of PL/I source code, generates equivalent Java source, optionally compiles it with javac, and can run the resulting class. The project is intended as a practical proof-of-concept and learning tool for converting simple PL/I programs to Java.

This repository contains:

• plijava.py — main transpiler (lexer, parser, code generator, runner)
• pl1code/ — example PL/I input files used as test cases
• javalib/ — Java runtime helpers (DriverShim, PliJavaRuntime, RndRuntime)
• run.py — small non-interactive wrapper to run the transpiler
• requirements.txt — Python dependencies
• tests/ — minimal pytest integration tests

Status: functional proof-of-concept. The tool supports a useful subset of PL/I but is not a complete PL/I translator. See the code and tests for specifics.

Features

• Parse PL/I procedure definitions and declarations
• Translate basic statements: assignments, arithmetic, if, do loops, select/when, put/skip output
• One- and two-dimensional arrays (integer indexing)
• Record-style declarations (basic support)
• exec sql "..." into var; support for simple SQL-to-variable mapping (MySQL/DB2 via JDBC)
• Generate helper classes for database access and random utilities
• Optional automatic invocation of javac and java to compile/run generated code

Architecture

1. plijava.py uses PLY (lex/yacc) to parse PL/I.
2. The parser emits Java source strings.
3. The script writes generated Java to <classname>.java, formats (optional), compiles with javac, and runs with java.

Requirements

• Python 3.8+
• Java Development Kit (JDK) with javac and java available (or set JAVA_HOME)
• Python dependencies (see requirements.txt): ply (and pytest for tests)
• MySQL Java JDBC driver (for MySQL support) or IBM's JDBC driver (for Db2 Community Edition)
• Optional: astyle open source Java formatter for beautified Java output

Installation

1. Clone or copy this repository into a working directory.
2. (Recommended) Create and activate a Python virtual environment:

python -m venv .venv
.\.venv\Scripts\Activate.ps1   # PowerShell on Windows

3. Install Python dependencies:

pip install -r requirements.txt

4. Ensure a JDK is installed and either:
   • set JAVA_HOME (recommended), or
   • have javac/java on your PATH.

How to run

• Tested only under Windows 11
• Call the program: python plijava.py
• Select your PL/I input file in the explorer window
• If you want to include SQL statements, store your credentials in c:/temp/creds.txt (location can be overridden with PLIJAVA_CREDS_FILE).

Usage

Interactive (file dialog):

python plijava.py

Non-interactive (useful for CI or scripts):

python run.py --input pl1code/simple.pli

Environment variables supported:

• PLIJAVA_INPUT_FILE — path to PL/I input file
• PLIJAVA_CREDS_FILE — path to credentials file for SQL operations (falls back to c:/temp/creds.txt)
• PLIJAVA_DEBUG — set to 1 or true to enable debug logging
• JAVA_HOME / JDK_HOME — used to locate javac/java if not on PATH

Credentials file format (single record):

host="localhost", user="root", password="secret", database="sakila", dbsys="mysql", jdbc_path="C:/path/to/mysql-connector.jar", port="3306"

Running tests

pytest -q

Tests exercise that plijava.py runs and, if javac is present, attempt to compile generated Java.

Version history

Version 1.00

• dcl variable-name <fixed bin(15|31) | char(length)>;
• variable = <arithmetic-expression> | <string-expression>;
• operators in arithmetic_expression: + - * / ( )
• operators in string-expression: builtins: substr index decimal
• if relational-expression then statement else statement;
• select(expression) when(value) statement; other statement; end;
• put skip list(variable | constant);
• one-dimensional arrays (only integer indexing)
• record i/o simple version (open close read write)
• do-while loop

Version 1.01

• exec sql "select sql-select-field" into variable; — MySQL and Db2 connection
• get list(variable-list); — read variables from console per prompt

Development notes & limitations

• The transpiler implements a useful subset of PL/I; many features are not supported or are partially supported (see code comments).
• Developed primarily on Windows; path handling is Windows-oriented.
• parsetab.py is generated by PLY; regenerate it only when grammar changes.
• Avoid committing real credentials — use PLIJAVA_CREDS_FILE to point to a local file outside the repo.

License

This repository is provided as-is for educational and experimental use.