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39 lines
848 B
Markdown
39 lines
848 B
Markdown
# Generator Pattern
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[Generators](https://en.wikipedia.org/wiki/Generator_(computer_programming)) yields a sequence of values one at a time.
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## Implementation
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```go
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func Count(start int, end int) chan int {
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ch := make(chan int)
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go func(ch chan int) {
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for i := start; i <= end ; i++ {
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// Blocks on the operation
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ch <- i
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}
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close(ch)
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}(ch)
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return ch
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}
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```
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## Usage
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```go
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fmt.Println("No bottles of beer on the wall")
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for i := range Count(1, 99) {
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fmt.Println("Pass it around, put one up,", i, "bottles of beer on the wall")
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// Pass it around, put one up, 1 bottles of beer on the wall
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// Pass it around, put one up, 2 bottles of beer on the wall
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// ...
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// Pass it around, put one up, 99 bottles of beer on the wall
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}
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fmt.Println(100, "bottles of beer on the wall")
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```
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