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//
// section-parse.go: scan standard input and do the following:
//
// 1. look for a section that begins with "test-text "STUFF/foo" and ends
// with a blank line.
// 2. print the "bar.DIGITS" suffix for each line in the section
//
// Build:
//
// go build section-parse.go
//
// Alternatively, you can run this script directly like this:
//
// go run ./section-parse.go < input.txt
//
// Example:
//
// > go run ./section-parse.go < input.txt
// bar.1
// bar.2
// bar.3
// bar.4
//
package main
import (
"fmt"
"io"
"log"
"os"
"regexp"
"strings"
)
// section header regex
var headerRe = regexp.MustCompile(`^test-text ".*/foo"$`)
// section footer regex
var footerRe = regexp.MustCompile(`^\s*$`)
// body line regex
var bodyRe = regexp.MustCompile(`^.*(bar\.\d+)$`)
// Is the given line a section header?
func isHeader(s string) bool {
return headerRe.MatchString(s)
}
// Is the given line a section footer?
func isFooter(s string) bool {
return footerRe.MatchString(s)
}
// Read slice of lines from standard input.
func getLines() []string {
// read from standard input
buf, err := io.ReadAll(os.Stdin)
if err != nil {
log.Fatal(err)
}
// split into lines, return result
return strings.Split(string(buf), "\n")
}
func main() {
inBody := false
// walk lines
for _, line := range(getLines()) {
if (!inBody && isHeader(line)) || (inBody && isFooter(line)) {
// toggle state
inBody = !inBody
} else if inBody {
// match digits, check for error
md := bodyRe.FindStringSubmatch(line)
if len(md) < 2 {
log.Fatalf("invalid body line: %s", line)
}
// print match to standard output
fmt.Println(md[1])
}
}
}
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