move: log parser variadics to its own lecture

27-functions-advanced/07-log-parser/main.go

@@ -11,7 +11,6 @@ import (
 	"bufio"
 	"fmt"
 	"os"
-	"sort"
 	"strings"
 )
 
@@ -30,15 +29,13 @@ func main() {
 
 // summarize summarizes and prints the parsing result
 func summarize(p *parser) {
-	sort.Strings(p.domains)
-
 	fmt.Printf("%-30s %10s\n", "DOMAIN", "VISITS")
 	fmt.Println(strings.Repeat("-", 45))
 
-	for _, domain := range p.domains {
+	loop(p, func(r result) {
-		fmt.Printf("%-30s %10d\n", domain, p.sum[domain].visits)
+		fmt.Printf("%-30s %10d\n", r.domain, r.visits)
-	}
+	})
-	fmt.Printf("\n%-30s %10d\n", "TOTAL", p.total)
+	fmt.Printf("\n%-30s %10d\n", "TOTAL", totalVisits(p))
 }
 
 // dumpErrs simplifies handling multiple errors

27-functions-advanced/07-log-parser/parser.go

@@ -9,6 +9,7 @@ package main
 
 import (
 	"fmt"
+	"sort"
 	"strconv"
 	"strings"
 )
@@ -59,7 +60,7 @@ func parse(p *parser, line string) (r result) {
 	return
 }
 
-// update updates the errors for the given parsing result
+// update updates all the parsing results using the given parsing result
 func update(p *parser, r result) {
 	if p.lerr != nil {
 		return
@@ -84,3 +85,17 @@ func update(p *parser, r result) {
 func err(p *parser) error {
 	return p.lerr
 }
+
+// loop allows a func to access all the copies of parsing results
+func loop(p *parser, feed func(result)) {
+	sort.Strings(p.domains)
+
+	for _, domain := range p.domains {
+		feed(p.sum[domain])
+	}
+}
+
+// total returns the total visits
+func totalVisits(p *parser) int {
+	return p.total
+}