29 lines
562 B
Go
29 lines
562 B
Go
package go_koans
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func aboutInterfaces() {
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mspaint := &program{3} // mspaint is a kind of *program, which is a valid 'runner'
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runOnce(mspaint) // runOnce takes an abstract 'runner' type
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assert(mspaint.runTimes == __int__) // conformed interfaces need not be declared, they are inferred
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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 runOnce(r runner) {
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r.run()
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}
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// concrete type implementing the interface
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type program struct {
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runTimes int
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}
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func (self *program) run() {
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self.runTimes++
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}
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