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

SPy (Static Python) is a new language variant/compiler that aims to be as fast as C while maintaining Python-like syntax and features

Key differences from Python include:

• Formalized execution phases (import time vs runtime)
• Static type checking and enforcement
• Restricted dynamism for better compilation
• Type annotations are actually enforced

Performance improvements achieved through:

• Partial evaluation (“redshifting”) to optimize code at import time
• Static type-based operation dispatch
• Compilation to native code via C
• Removal of dynamic lookup overhead

Multiple compilation targets supported:

• Native code (via C)
• WebAssembly (via Emscripten)
• JavaScript interop

Core design principles:

• No “performance cliffs” - predictable optimization
• Maintain Pythonic feel and features where possible
• Simple implementation and mental model
• Focus on common Python usage patterns

Current status:

• Work in progress/prototype stage
• Basic features working including functions, classes, types
• Missing some Python features like lists/dicts
• Open source on GitHub (spylang/spy)

Use cases include:

• Numerical computation
• Performance-critical modules
• WebAssembly compilation
• Alternative to Cython for extensions

Not meant to be 100% Python compatible - intentionally restricts some dynamic features to enable better optimization