Glyph Runtime

The Glyph runtime provides an immutable-first virtual machine (VM) for executing Glyph programs with capability-based security.

Features

Immutable-First Design

• All values are immutable - operations create new values rather than modifying existing ones
• Variable bindings are immutable (no reassignment allowed)
• Collection operations (append, insert, etc.) return new collections
• Side effects only through capability-controlled intrinsics

Stack-Based Execution

• Efficient stack-based VM with configurable limits
• Support for nested function calls with proper frame management
• Automatic memory management with configurable limits

Capability-Based Security

• Programs must declare required capabilities upfront
• Fine-grained permission system for:
  • Audio synthesis (audio.speak)
  • Network access (network.fetch with URL patterns)
  • Display operations (display.chart, display.image)
  • User interaction (wait.confirm)
  • Memory limits
• Runtime enforcement prevents unauthorized operations

Comprehensive Instruction Set

• Arithmetic: Add, Sub, Mul, Div, Mod, Pow
• Comparison: Eq, Ne, Lt, Le, Gt, Ge
• Logical: And, Or, Not
• Stack manipulation: Push, Pop, Dup, Swap, Rot3
• Control flow: Jump, JumpIf, JumpIfNot, Call, Return
• Data structures: MakeList, MakeDict, ListAppend, DictInsert
• Pattern matching: Match, MatchValue, MatchType
• Intrinsics: CallIntrinsic for built-in functions
• Debugging: TraceValue, RecordTelemetry

Usage

use glyph_runtime::{VM, VMConfig, Instruction, Value, Capability};

// Configure VM with capabilities
let mut config = VMConfig::default();
config.capabilities.grant(Capability::AudioSpeak);

// Create VM instance
let mut vm = VM::new(config);

// Load bytecode program
vm.load_bytecode(vec![vec![
    Instruction::Push(Value::Str("Hello, Glyph!".to_string())),
    Instruction::CallIntrinsic("voice.speak".to_string()),
    Instruction::Halt,
]]);

// Execute program
match vm.execute() {
    Ok(result) => println!("Result: {}", result),
    Err(e) => eprintln!("Error: {}", e),
}

Architecture

VM Structure

VM
├── Stack (configurable size)
├── Call Frames (function contexts)
├── Global bindings (immutable)
├── Capability set (granted permissions)
├── Memory manager (tracks allocations)
└── Telemetry collector

Execution Model

1. Instructions are fetched from bytecode
2. Stack-based operations manipulate values
3. Call frames manage function scope
4. Capabilities are checked before intrinsics
5. Memory limits are enforced continuously

Examples

See the examples/ directory for:

• simple_vm.rs - Basic arithmetic and list operations
• capability_demo.rs - Capability-based security demonstrations
• vm_benchmark.rs - Performance benchmarks

Performance

The VM is designed for:

• Cold start: ≤ 150ms
• Arithmetic operations: > 4 ops/ms
• Memory efficiency: < 10MB for basic programs
• Deterministic execution with seed-based randomness