Go extract experiments

extract_test.go

package extract_test

import (
	"regexp"
	"strings"
	"testing"
)

func lines(source string) chan string {
	output := make(chan string)
	go func() {
		for _, line := range strings.Split(source, "\n") {
			output <- line
		}
		close(output)
	}()
	return output
}

func Extract1(beginMark, endMark string, input chan string) chan string {
	output := make(chan string)
	go func() {
		for line := range input {
			if line == beginMark {
				for line := range input {
					if line == endMark {
						break
					}
					output <- line
				}
			}
		}
		close(output)
	}()

	return output
}

func Extract2(beginMark, endMark string, input chan string) chan string {
	output := make(chan string)
	go func() {
		for line, ok := <-input; ok; line, ok = <-input {
			for ; ok; line, ok = <-input {
				if line == beginMark {
					line, ok = <-input
					break
				}
			}

			for ; ok; line, ok = <-input {
				if line == endMark {
					break
				}
				output <- line
			}
		}
		close(output)
	}()

	return output
}

func TestExtract(t *testing.T) {
	text := regexp.MustCompile(`(?m)^[ \t]*`).ReplaceAllString(`
		1 Lorem ipsum dolor sit amet, consectetur adipisicing elit. 
		Expedita illo aliquid id labore distinctio. 
		
		BEGIN
		2 Quos debitis pariatur ex ipsa, vel dignissimos et cumque
		odit provident, adipisci consequatur nobis, tempore sunt.
		END
		
		3 Lorem ipsum dolor sit amet, consectetur adipisicing elit. 
		Expedita illo aliquid id labore distinctio. 
		
		BEGIN
		4 Quos debitis pariatur ex ipsa, vel dignissimos et cumque
		odit provident, adipisci consequatur nobis, tempore sunt.
		END

		5 Lorem ipsum dolor sit amet, consectetur adipisicing elit. 
		Expedita illo aliquid id labore distinctio. 
	`, "")

	t.Log(text)

	extracted := Extract1("BEGIN", "END", lines(text))

	for line := range extracted {
		t.Log(line)
	}
}