godbc

README

godbc

Design by contract for Go

Installation

To install godbc, use go get:

go get github.com/lpabon/godbc

Import the godbc package into your code using this template:

import (
  "github.com/lpabon/godbc"
)

Documentation

Documentation is available at https://godoc.org/github.com/lpabon/godbc

Documentation

Overview

Design-by-Contract for Go

Design by Contract is a programming methodology which binds the caller and the function called to a contract. The contract is represented using Hoare Triple:

{P} C {Q}

where {P} is the precondition before executing command C, and {Q} is the postcondition.

See Also

* http://en.wikipedia.org/wiki/Design_by_contract * http://en.wikipedia.org/wiki/Hoare_logic * http://dlang.org/dbc.html

Usage

Godbc is enabled by default, but can be disabled for production builds by using the tag 'prod' in builds and tests as follows:

go build -tags 'prod'

or

go test -tags 'prod'

Index

• func Check(b bool, message ...interface{})
• func Ensure(b bool, message ...interface{})
• func Invariant(obj InvariantTester, message ...interface{})
• func InvariantSimple(obj InvariantSimpleTester, message ...interface{})
• func Require(b bool, message ...interface{})
• type InvariantSimpleTester
• type InvariantTester

Functions

func Check

func Check(b bool, message ...interface{})

Check provides a simple assert

func Ensure

func Ensure(b bool, message ...interface{})

Ensure checks the postconditions are satisfied before returning to the caller.

Example Code

type Data struct {
	a int
}

func (*d Data) Set(a int) {
	d.a = a
	godbc.Ensure(d.a == a)
}

func Invariant

func Invariant(obj InvariantTester, message ...interface{})

Invariant calls the objects Invariant() receiver to test the object for correctness.

The caller object must provide an object that supports the interface InvariantTester

To see an example, please take a look at the godbc_test.go

func InvariantSimple

func InvariantSimple(obj InvariantSimpleTester, message ...interface{})

InvariantSimple calls the objects Invariant() receiver to test the object for correctness.

The caller object must provide an object that supports the interface InvariantSimpleTester and does not need to provide a String() receiver

func Require

func Require(b bool, message ...interface{})

Require checks that the preconditions are satisfied before executing the function

Example Code

func Divide(a, b int) int {
	godbc.Require(b != 0)
	return a/b
}

Types

type InvariantSimpleTester

type InvariantSimpleTester interface {
	Invariant() bool
}

InvariantSimpleTester is an interface which provides a receiver to test the object

type InvariantTester

type InvariantTester interface {
	InvariantSimpleTester
	String() string
}

InvariantTester is an interface which provides not only an Invariant(), but also a receiver to print the structure