add: new interfaces

interfaces/refactor-notes/refactor-01/parser.go

@@ -0,0 +1,57 @@
+// For more tutorials: https://blog.learngoprogramming.com
+//
+// Copyright © 2018 Inanc Gumus
+// Learn Go Programming Course
+// License: https://creativecommons.org/licenses/by-nc-sa/4.0/
+//
+
+package main
+
+import (
+	"bufio"
+	"fmt"
+	"os"
+)
+
+// parser keeps track of the parsing
+type parser struct {
+	sum     map[string]result // metrics per domain
+	domains []string          // unique domain names
+}
+
+// newParser constructs, initializes and returns a new parser
+func newParser() *parser {
+	return &parser{sum: make(map[string]result)}
+}
+
+// parse the log lines and return results
+func parse(p *parser) error {
+	var (
+		l  = 1
+		in = bufio.NewScanner(os.Stdin)
+	)
+
+	for in.Scan() {
+		r, err := parseResult(in.Text())
+		if err != nil {
+			return fmt.Errorf("line %d: %v", l, err)
+		}
+
+		l++
+
+		update(p, r)
+	}
+
+	return in.Err()
+}
+
+// update the parsing results
+func update(p *parser, r result) {
+	// Collect the unique domains
+	if _, ok := p.sum[r.domain]; !ok {
+		p.domains = append(p.domains, r.domain)
+	}
+
+	// create and assign a new copy of `visit`
+	p.sum[r.domain] = addResult(r, p.sum[r.domain])
+}