This module provides a draft of Golang package with implementation of collection of decorators that makes it easy to write software using contracts.

Contracts are a debugging and verification tool. They are declarative statements about what states a program must be in to be considered "correct" at runtime. They are similar to assertions, and are verified automatically at various well-defined points in the program. Contracts can be specified on functions and on classes.

Contracts consist of two parts: a description and a condition. The description is simply a human-readable string that describes what the contract is testing, while the condition is a single function that tests that condition. The condition is executed automatically and passed certain arguments (which vary depending on the type of contract), and must return a boolean value: True if the condition has been met, and False otherwise.

The main idea of using contracts was described in Applying 'design by contract' by B. Meyer.