Talks - Antonio Cuni: SPy (Static Python) lang: fast as C, Pythonic as Python

SPy (Static Python) aims to be a fast, compilable subset of Python that maintains Pythonic feel while removing features that make compilation difficult

Key differences from standard Python:

• Static typing is strictly enforced
• Immutable by default after initialization phase
• Static dispatch instead of dynamic dispatch
• Three distinct execution phases: import time, freeze phase, runtime

Compilation approach:

• Uses “redshift” process to evaluate and optimize away “blue” nodes (compile-time logic)
• Remaining “red” nodes represent runtime operations
• Can generate C code, WebAssembly, or C Python extensions

Performance optimizations:

• Pre-computes and resolves lookups at compile time
• Eliminates dynamic dispatch overhead
• Allows direct memory access for struct-like classes
• Specializes functions based on types

Development goals:

• Easy to implement and understand
• Opt-in approach - use .spy extension for SPy features
• Integration with existing Python ecosystem
• Support for WebAssembly target
• Focus on compile-time optimization while maintaining high-level API

Trade-offs:

• Not 100% Python compatible
• Removes some dynamic Python features
• Requires explicit type annotations
• More restrictive semantics than Python

Use cases:

• Performance-critical code
• WebAssembly applications
• Systems programming in Python
• Typed APIs and frameworks