OMG Runtime

The OMG Runtime is the execution engine for the OMG programming language — a personal, educational language project designed to explore the full stack of compiler and interpreter implementation.

This crate provides:

A stack-based virtual machine for executing OMG bytecode
A tree-walk REPL for interactive exploration
A bytecode loader and function table format
A set of built-in functions for data, math, and filesystem operations
A well-defined error system for reporting runtime failures

Features

🎛️ Virtual Machine

Operand stack evaluation model
Global and local variable environments
Function call frames (with tail call optimization)
Exception-style error handling (setup_except, raise, pop_block)

⚙️ Instruction Set

Supports all major categories of instructions:

Literals: integers, strings, booleans, None
Arithmetic & Bitwise: + - * / % & | ^ << >> ~
Logical & Comparison: == != < <= > >= and or
Structures: list/dict building, indexing, slicing, attributes
Control Flow: jumps, conditional jumps, function calls, returns
Exceptions: assert, raise, setup_except
I/O: emit to stdout

🛠 Built-in Functions

Out-of-the-box helpers for everyday use:

Conversion: chr, ascii, hex, binary
Introspection: length
Data: freeze (immutable dicts)
Errors: panic, raise
Filesystem: read_file, file_exists
File I/O (descriptor-based): file_open, file_read, file_write, file_close
Meta: call_builtin

⚡ REPL

Interactive interpreter for OMG source code:

Prompts with >>> and supports multiline input (...)
Tracks brace depth for entering whole blocks
Preserves state across commands
Exits cleanly with exit / quit

🧩 Error System

Two-layer error handling:

ErrorKind – compact categories (for bytecode raise ops)
RuntimeError – detailed structured errors (with Display messages)

Examples:

AssertionError
TypeError("expected integer")
IndexError("out of bounds")
VmInvariant("stack underflow")

Example

;;;omg

proc greeting(name) {
    return "Hello " + name
}

emit greeting("World")

alloc xs := [1, 2, 3]
emit "length(xs) = " + length(xs)

# Assertions and loops
facts 2 + 2 == 4

alloc i := 0
loop i < 3 {
    emit "i = " + i
    i := i + 1
}

Compile to bytecode (.omgb) or run directly through the embedded interpreter.

Using the REPL

$ cargo run

OMG Language Interpreter - REPL

Type `exit` or `quit` to leave.

>>> alloc x := 5

>>> emit x * 2

10

Installation

Add to your project:

[dependencies]

omg_runtime = "0.1.2"

Or install the runtime directly:

cargo install omg_runtime

License

Licensed under the MIT License.

Project Status

OMG is an educational project. The runtime is stable enough to run example scripts and bytecode, but the language is not serious. Expect breaking changes as new features are added.

omg_runtime 0.1.4