1. Five Core Restrictions
Libraries are powerful because of strict rules:
Stateless: no state variables allowed.
No inheritance: cannot inherit or be inherited.
Indestructible: no selfdestruct.
No payable/fallback: can’t hold ETH.
No abstract functions: all must be fully implemented.
These restrictions ensure predictability, safety, and trustworthiness.
2. The Magic of using for — Extending Data Types
Normal call: Math.max(numbers)
With using for:
using Math for int[];
numbers.max();
Compiler automatically passes the variable (numbers) as the first argument.
Convention: call this parameter self (like this in OOP).
This makes Solidity code feel more object-oriented.
Conclusion
Solidity libraries are much more than a toolbox:
Strict safety rules keep them pure and reliable.
using for adds elegance and OOP-like syntax.
Off-chain calls may be free, but on-chain execution still costs Gas.
Deployable as shared infrastructure → true on-chain microservices.
They’re not just helpers — they’re a core design pattern for secure, efficient, and modular smart contracts.
Top comments (0)