refactor: oop log parser names

interfaces/log-parser/oop/group.go

@@ -33,7 +33,7 @@ func (g *group) digest(results iterator) error {
 			g.keys = append(g.keys, k)
 		}
 
-		g.sum[k] = r.add(g.sum[k])
+		g.sum[k] = r.sum(g.sum[k])
 	})
 }
 

interfaces/log-parser/oop/main.go

@@ -29,7 +29,7 @@ func main() {
 	pipe := newPipeline(
 		newTextLog(os.Stdin),
 		newTextReport(),
-		filterBy(domainExtFilter("com", "io")),
+		filterBy(notUsing(domainExtFilter("com", "io"))),
 		groupBy(domainGrouper),
 	)
 

interfaces/log-parser/oop/result.go

@@ -16,7 +16,7 @@ type result struct {
 	uniques int
 }
 
-func (r result) add(other result) result {
+func (r result) sum(other result) result {
 	r.visits += other.visits
 	r.uniques += other.uniques
 	return r
@@ -31,18 +31,24 @@ func (r *result) UnmarshalText(p []byte) (err error) {
 
 	r.domain, r.page = fields[0], fields[1]
 
-	r.visits, err = strconv.Atoi(fields[2])
-	if err != nil || r.visits < 0 {
-		return fmt.Errorf("wrong input %q", fields[2])
+	if r.visits, err = parseStr("visits", fields[2]); err != nil {
+		return err
 	}
-
-	r.uniques, err = strconv.Atoi(fields[3])
-	if err != nil || r.uniques < 0 {
-		return fmt.Errorf("wrong input %q", fields[3])
+	if r.uniques, err = parseStr("uniques", fields[3]); err != nil {
+		return err
 	}
 	return nil
 }
 
+// parseStr helps UnmarshalText for string to positive int parsing
+func parseStr(name, v string) (int, error) {
+	n, err := strconv.Atoi(v)
+	if err != nil || n < 0 {
+		return 0, fmt.Errorf("result.UnmarshalText %q: %v", name, err)
+	}
+	return n, nil
+}
+
 // UnmarshalJSON to a *result
 func (r *result) UnmarshalJSON(data []byte) error {
 	var re struct {

interfaces/log-parser/oop/textreport.go

@@ -37,7 +37,7 @@ func (s *textReport) digest(results iterator) error {
 
 	var total result
 	results.each(func(r result) {
-		total = total.add(r)
+		total = total.sum(r)
 
 		write(w, "%s\t%s\t%d\t%d\n", r.domain, r.page, r.visits, r.uniques)
 	})