49 lines
1.1 KiB
Go
49 lines
1.1 KiB
Go
package go_koans
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func aboutInterfaces() {
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bob := new(human) // bob is a kind of *human
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rspec := new(program) // rspec is a kind of *program
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assert(runner(bob) == __runner__) // conformed interfaces need not be declared, they are inferred
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assert(bob.milesCompleted == 0)
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assert(rspec.executionCount == 0)
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runTwice(bob) // bob fits the profile for a 'runner'
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runTwice(rspec) // rspec also fits the profile for a 'runner'
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assert(bob.milesCompleted == __int__) // bob is affected by running in his own unique way (probably fatigue)
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assert(rspec.executionCount == __int__) // rspec can run completely differently than bob, thanks to interfaces
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}
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// abstract interface and function that requires it
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type runner interface {
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run()
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}
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func runTwice(r runner) {
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r.run()
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r.run()
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}
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// concrete type implementing the interface
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type human struct {
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milesCompleted int
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}
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func (self *human) run() {
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self.milesCompleted++
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}
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// another concrete type implementing the interface
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type program struct {
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executionCount int
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}
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func (self *program) run() {
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self.executionCount++
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}
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