move: interfaces error handling and advanced funcs

27-functional-programming/_legacy/01-variadic-funcs/main.go

@@ -1,73 +0,0 @@
-// 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 "fmt"
-
-func main() {
-	nums := []int{2, 3, 7}
-	fmt.Printf("nums            : %d\n", nums)
-
-	n := avgNoVariadic(nums)
-	fmt.Printf("avgNoVariadic   : %d\n", n)
-
-	n = avg(2, 3, 7)
-	fmt.Printf("avg(2, 3, 7)    : %d\n", n)
-
-	n = avg(2, 3, 7, 8)
-	fmt.Printf("avg(2, 3, 7, 8) : %d\n", n)
-
-	// use ... to pass a slice
-	n = avg(nums...)
-	fmt.Printf("avg(nums...)    : %d\n", n)
-
-	// uses the existing slice
-	double(nums...)
-	fmt.Printf("double(nums...) : %d\n", nums)
-
-	// creates a new slice
-	double(4, 6, 14)
-	fmt.Printf("double(4, 6, 14): %d\n", nums)
-
-	// creates a nil slice
-	fmt.Printf("\nmain.nums       : %p\n", nums)
-	investigate("passes main.nums", nums...)
-	investigate("passes main.nums", nums...)
-	investigate("passes args", 4, 6, 14)
-	investigate("passes args", 4, 6, 14)
-	investigate("no args")
-}
-
-func investigate(msg string, nums ...int) {
-	fmt.Printf("investigate.nums: %12p  ->  %s\n", nums, msg)
-
-	if len(nums) > 0 {
-		fmt.Printf("\tfirst element: %d\n", nums[0])
-	}
-}
-
-func double(nums ...int) {
-	for i := range nums {
-		nums[i] *= 2
-	}
-}
-
-func avg(nums ...int) int {
-	return sum(nums) / len(nums)
-}
-
-func avgNoVariadic(nums []int) int {
-	return sum(nums) / len(nums)
-}
-
-func sum(nums []int) (total int) {
-	for _, n := range nums {
-		total += n
-	}
-	return
-}

27-functional-programming/_legacy/02-func-values/main.go

@@ -1,52 +0,0 @@
-// 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 "fmt"
-
-type filterFunc func(int) bool
-
-func main() {
-	signatures()
-	funcValues()
-}
-
-func isEven(n int) bool {
-	return n%2 == 0
-}
-
-func isOdd(m int) bool {
-	return m%2 == 1
-}
-
-func signatures() {
-	fmt.Println("••• FUNC SIGNATURES (TYPES) •••")
-	fmt.Printf("isEven     : %T\n", isEven)
-	fmt.Printf("isOdd      : %T\n", isOdd)
-}
-
-func funcValues() {
-	fmt.Println("\n••• FUNC VALUES (VARS) •••")
-
-	// var value func(int) bool
-	var value filterFunc
-	fmt.Printf("value nil? : %t\n", value == nil)
-
-	value = isEven
-	fmt.Printf("value(2)   : %t\n", value(2))
-	fmt.Printf("isEven(2)  : %t\n", isEven(2))
-
-	value = isOdd
-	fmt.Printf("value(1)   : %t\n", value(1))
-	fmt.Printf("isOdd(1)   : %t\n", isOdd(1))
-
-	fmt.Printf("value nil? : %t\n", value == nil)
-	fmt.Printf("value      : %p\n", value)
-	fmt.Printf("isEven     : %p\n", isEven)
-	fmt.Printf("isOdd      : %p\n", isOdd)
-}

27-functional-programming/_legacy/03-func-to-func/main.go

@@ -1,82 +0,0 @@
-// 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 (
-	"fmt"
-	"strings"
-	"unicode"
-)
-
-type filterFunc func(int) bool
-
-func main() {
-	signatures()
-
-	fmt.Println("\n••• WITHOUT FUNC VALUES •••")
-	nums := []int{1, 2, 3, 4, 5, 6, 7, 8, 9, 10}
-
-	fmt.Printf("evens      : %d\n", filterEvens(nums...))
-	fmt.Printf("odds       : %d\n", filterOdds(nums...))
-
-	fmt.Println("\n••• FUNC VALUES •••")
-	fmt.Printf("evens      : %d\n", filter(isEven, nums...))
-	fmt.Printf("odds       : %d\n", filter(isOdd, nums...))
-
-	fmt.Println("\n••• MAPPING •••")
-	fmt.Println(strings.Map(unpunct, "hello!!! HOW ARE YOU???? :))"))
-	fmt.Println(strings.Map(unpunct, "TIME IS UP!"))
-}
-
-func unpunct(r rune) rune {
-	if unicode.IsPunct(r) {
-		return -1
-	}
-	return unicode.ToLower(r)
-}
-
-func filter(f filterFunc, nums ...int) (filtered []int) {
-	for _, n := range nums {
-		if f(n) {
-			filtered = append(filtered, n)
-		}
-	}
-	return
-}
-
-func filterOdds(nums ...int) (filtered []int) {
-	for _, n := range nums {
-		if isOdd(n) {
-			filtered = append(filtered, n)
-		}
-	}
-	return
-}
-
-func filterEvens(nums ...int) (filtered []int) {
-	for _, n := range nums {
-		if isEven(n) {
-			filtered = append(filtered, n)
-		}
-	}
-	return
-}
-
-func isEven(n int) bool {
-	return n%2 == 0
-}
-
-func isOdd(m int) bool {
-	return m%2 == 1
-}
-
-func signatures() {
-	fmt.Println("••• FUNC SIGNATURES (TYPES) •••")
-	fmt.Printf("isEven     : %T\n", isEven)
-	fmt.Printf("isOdd      : %T\n", isOdd)
-}

27-functional-programming/_legacy/04-closures/main.go

@@ -1,76 +0,0 @@
-// 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 "fmt"
-
-type filterFunc func(int) bool
-
-func main() {
-	nums := []int{1, 2, 3, 4, 5, 6, 7, 8, 9, 10}
-
-	fmt.Println("••• FUNC VALUES •••")
-	fmt.Printf("evens      : %d\n", filter(isEven, nums...))
-	fmt.Printf("odds       : %d\n", filter(isOdd, nums...))
-	fmt.Printf("> 3        : %d\n", filter(greaterThan3, nums...))
-	fmt.Printf("> 6        : %d\n", filter(greaterThan6, nums...))
-
-	// ========================================================================
-
-	fmt.Println("\n••• CLOSURES •••")
-
-	var min int
-	greaterThan := func(n int) bool {
-		return n > min
-	}
-
-	min = 3
-	fmt.Printf("> 3        : %d\n", filter(greaterThan, nums...))
-
-	min = 6
-	fmt.Printf("> 6        : %d\n", filter(greaterThan, nums...))
-
-	// min = 1
-	// fmt.Printf("> 1        : %d\n", filter(greaterThan, nums...))
-	// min = 2
-	// fmt.Printf("> 2        : %d\n", filter(greaterThan, nums...))
-	// min = 3
-	// fmt.Printf("> 3        : %d\n", filter(greaterThan, nums...))
-
-	var filterers []filterFunc
-	for i := 1; i <= 3; i++ {
-		current := i
-
-		filterers = append(filterers, func(n int) bool {
-			min = current
-			return greaterThan(n)
-		})
-	}
-
-	printer(filterers, nums...)
-}
-
-func printer(filterers []filterFunc, nums ...int) {
-	for i, filterer := range filterers {
-		fmt.Printf("> %d        : %d\n", i+1, filter(filterer, nums...))
-	}
-}
-
-func greaterThan6(n int) bool { return n > 6 }
-func greaterThan3(n int) bool { return n > 3 }
-func isEven(n int) bool       { return n%2 == 0 }
-func isOdd(m int) bool        { return m%2 == 1 }
-
-func filter(f filterFunc, nums ...int) (filtered []int) {
-	for _, n := range nums {
-		if f(n) {
-			filtered = append(filtered, n)
-		}
-	}
-	return
-}

27-functional-programming/_legacy/05-higher-order-funcs/main.go

@@ -1,58 +0,0 @@
-// 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 (
-	"fmt"
-)
-
-type filterFunc func(int) bool
-
-func main() {
-	fmt.Println("••• HIGHER-ORDER FUNCS •••")
-
-	nums := []int{1, 2, 3, 4, 5, 6, 7, 8, 9, 10}
-
-	odd := reverse(reverse(isEven))
-	fmt.Printf("reversed   : %t\n", odd(8))
-
-	fmt.Printf("> 3        : %d\n", filter(greater(3), nums...))
-	fmt.Printf("> 6        : %d\n", filter(greater(6), nums...))
-	fmt.Printf("<= 6       : %d\n", filter(lesseq(6), nums...))
-	fmt.Printf("<= 6       : %d\n", filter(reverse(greater(6)), nums...))
-}
-
-func reverse(f filterFunc) filterFunc {
-	return func(n int) bool {
-		return !f(n)
-	}
-}
-
-func greater(min int) filterFunc {
-	return func(n int) bool {
-		return n > min
-	}
-}
-
-func lesseq(max int) filterFunc {
-	return func(n int) bool {
-		return n <= max
-	}
-}
-
-func filter(f filterFunc, nums ...int) (filtered []int) {
-	for _, n := range nums {
-		if f(n) {
-			filtered = append(filtered, n)
-		}
-	}
-	return
-}
-
-func isEven(n int) bool { return n%2 == 0 }
-func isOdd(m int) bool  { return m%2 == 1 }

27-functional-programming/_legacy/06-functional-programming/main.go

@@ -1,97 +0,0 @@
-// 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 (
-	"fmt"
-)
-
-type filterFunc func(int) bool
-
-func main() {
-	fmt.Println("••• HIGHER-ORDER FUNCS •••")
-
-	nums := []int{1, 2, 3, 4, 5, 6, 7, 8, 9, 10}
-
-	odd := reverse(reverse(isEven))
-	fmt.Printf("reversed   : %t\n", odd(8))
-
-	fmt.Printf("> 3        : %d\n", filter(greater(3), nums...))
-	fmt.Printf("> 6        : %d\n", filter(greater(6), nums...))
-	fmt.Printf("<= 6       : %d\n", filter(lesseq(6), nums...))
-	fmt.Printf("<= 6       : %d\n", filter(reverse(greater(6)), nums...))
-
-	fmt.Println("\n••• CLOSURES •••")
-	fmt.Printf("uniques    : %d\n", filter(uniques(), 1, 1, 2, 3, 3))
-
-	dups := reverse(uniques())
-	fmt.Printf("dups       : %v\n", filter(dups, 1, 1, 2, 3, 3))
-
-	dups = reverse(uniques())
-	fmt.Printf("dups dups  : %v\n", filter(dups, 1, 1, 2, 3, 3, 3, 3))
-
-	dups = reverse(uniques())
-	out := filter(dups, 1, 1, 2, 3, 3, 3, 3)
-	fmt.Printf("dups uniqs : %v\n", filter(uniques(), out...))
-
-	dups = reverse(uniques())
-	chained := chain(reverse(greater(1)), dups, uniques())
-	fmt.Printf("dups chain : %v\n", filter(chained, 1, 1, 2, 3, 3, 3, 3, 0, 0))
-}
-
-func chain(filters ...filterFunc) filterFunc {
-	return func(n int) bool {
-		for _, next := range filters {
-			if !next(n) {
-				return false
-			}
-		}
-		return true
-	}
-}
-
-func uniques() filterFunc {
-	seen := make(map[int]bool)
-
-	return func(n int) (ok bool) {
-		if !seen[n] {
-			seen[n], ok = true, true
-		}
-		return
-	}
-}
-
-func reverse(f filterFunc) filterFunc {
-	return func(n int) bool {
-		return !f(n)
-	}
-}
-
-func greater(min int) filterFunc {
-	return func(n int) bool {
-		return n > min
-	}
-}
-
-func lesseq(max int) filterFunc {
-	return func(n int) bool {
-		return n <= max
-	}
-}
-
-func filter(f filterFunc, nums ...int) (filtered []int) {
-	for _, n := range nums {
-		if f(n) {
-			filtered = append(filtered, n)
-		}
-	}
-	return
-}
-
-func isEven(n int) bool { return n%2 == 0 }
-func isOdd(m int) bool  { return m%2 == 1 }

27-functional-programming/log-parser-exp/Makefile

@@ -1,29 +0,0 @@
-SHELL := /bin/bash
-LINES = $$(wc -l log.txt | cut -f1 -d' ')
-ECHO_LINES = echo -e ">> log.txt has $(LINES) lines"
-
-s: 
-	time go run . < log.txt
-
-r: 
-	go run . < log.txt
-
-n ?= 18
-load: restore
-	@echo "enlarging the file with itself, please wait..."	
-
-	@for i in {1..$(n)}; do \
-		awk 1 log.txt log.txt > log_.txt; \
-		mv log_.txt log.txt; \
-		rm -f log_.txt; \
-	done
-	
-	@$(ECHO_LINES)
-
-restore:
-	@echo "restoring the file..."
-	@git checkout log.txt
-	@$(ECHO_LINES)
-
-lines:
-	@$(ECHO_LINES)

27-functional-programming/log-parser-exp/field.go

@@ -1,20 +0,0 @@
-package main
-
-import (
-	"fmt"
-	"strconv"
-)
-
-// field helps for field parsing
-type field struct{ err error }
-
-// uatoi parses an unsigned integer string and saves the error.
-// it assumes that the val is unsigned.
-// for ease of usability: it returns an int instead of uint.
-func (f *field) uatoi(name, val string) int {
-	n, err := strconv.Atoi(val)
-	if n < 0 || err != nil {
-		f.err = fmt.Errorf("incorrect field -> %q = %q", name, val)
-	}
-	return n
-}

27-functional-programming/log-parser-exp/filters.go

@@ -1,34 +0,0 @@
-package main
-
-import "strings"
-
-func noopFilter(r result) bool {
-	return true
-}
-
-func notUsing(filter filterFn) filterFn {
-	return func(r result) bool {
-		return !filter(r)
-	}
-}
-
-func domainExtFilter(domains ...string) filterFn {
-	return func(r result) bool {
-		for _, domain := range domains {
-			if strings.HasSuffix(r.domain, "."+domain) {
-				return true
-			}
-		}
-		return false
-	}
-}
-
-func domainFilter(domain string) filterFn {
-	return func(r result) bool {
-		return strings.Contains(r.domain, domain)
-	}
-}
-
-func orgDomainsFilter(r result) bool {
-	return strings.HasSuffix(r.domain, ".org")
-}

27-functional-programming/log-parser-exp/groupers.go

@@ -1,20 +0,0 @@
-package main
-
-// domainGrouper groups by domain.
-// but it keeps the other fields.
-// for example: it returns pages as well, but you shouldn't use them.
-// exercise: write a function that erases superfluous data.
-func domainGrouper(r result) string {
-	return r.domain
-}
-
-func pageGrouper(r result) string {
-	return r.domain + r.page
-}
-
-// groupBy allocates map unnecessarily
-func noopGrouper(r result) string {
-	// with something like:
-	// return randomStrings()
-	return ""
-}

27-functional-programming/log-parser-exp/log.txt

@@ -1,16 +0,0 @@
-learngoprogramming.com / 10 5
-learngoprogramming.com /courses 15 10
-learngoprogramming.com /courses 10 5
-learngoprogramming.com /articles 20 15
-learngoprogramming.com /articles 5 2
-golang.org / 40 20
-golang.org / 20 10
-golang.org /blog 45 25
-golang.org /blog 15 5
-blog.golang.org /courses 60 30
-blog.golang.org /courses 30 20
-blog.golang.org /updates 20 10
-blog.golang.org /reference 65 35
-blog.golang.org /reference 15 5
-inanc.io /about 30 15
-inanc.io /about 70 35

27-functional-programming/log-parser-exp/log_err_missing.txt

@@ -1,16 +0,0 @@
-learngoprogramming.com / 10 5
-learngoprogramming.com /courses 15 10
-learngoprogramming.com /courses 10 5
-learngoprogramming.com /articles 20 15
-learngoprogramming.com /articles 5 2
-golang.org / 40 20
-golang.org / 20 10
-golang.org /blog 45 25
-golang.org /blog 15 5
-blog.golang.org /updates
-blog.golang.org /updates 30 20
-blog.golang.org /updates 20 10
-blog.golang.org /reference 65 35
-blog.golang.org /reference 15 5
-inanc.io /about 30 15
-inanc.io /about 70 35

27-functional-programming/log-parser-exp/log_err_negative.txt

@@ -1,16 +0,0 @@
-learngoprogramming.com / 10 5
-learngoprogramming.com /courses 15 10
-learngoprogramming.com /courses 10 5
-learngoprogramming.com /articles 20 15
-learngoprogramming.com /articles 5 2
-golang.org / 40 20
-golang.org / 20 10
-golang.org /blog 45 -250
-golang.org /blog 15 5
-blog.golang.org /updates 60 30
-blog.golang.org /updates 30 20
-blog.golang.org /updates 20 10
-blog.golang.org /reference 65 35
-blog.golang.org /reference 15 5
-inanc.io /about 30 15
-inanc.io /about 70 35

27-functional-programming/log-parser-exp/log_err_str.txt

@@ -1,16 +0,0 @@
-learngoprogramming.com / 10 5
-learngoprogramming.com /courses 15 10
-learngoprogramming.com /courses 10 5
-learngoprogramming.com /articles 20 15
-learngoprogramming.com /articles 5 2
-golang.org / 40 TWENTY
-golang.org / 20 10
-golang.org /blog 45 25
-golang.org /blog 15 5
-blog.golang.org /updates 60 30
-blog.golang.org /updates 30 20
-blog.golang.org /updates 20 10
-blog.golang.org /reference 65 35
-blog.golang.org /reference 15 5
-inanc.io /about 30 15
-inanc.io /about 70 35

27-functional-programming/log-parser-exp/main.go

@@ -1,59 +0,0 @@
-// 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 (
-	"fmt"
-)
-
-func main() {
-	defer recoverErr()
-
-	_, err := newPipeline().
-		// from(fastTextReader(os.Stdin)).
-		filterBy(notUsing(domainExtFilter("com", "io"))).
-		groupBy(domainGrouper).
-		start()
-
-	if err != nil {
-		fmt.Println("> Err:", err)
-	}
-}
-
-func recoverErr() {
-	val := recover()
-
-	if val == nil {
-		return
-	}
-
-	fmt.Println("> Error occurred:", val)
-}
-
-/*
-newReport -> report.New().
-Result    -> report.Line
-
-notUsing = report.Not
-
-pl := newPipeline(pipeOpts{
-  from:     fastTextReader(os.Stdin),
-  filterBy: notUsing(domainExtFilter("com", "io")),
-  groupBy:  domainGrouper,
-})
-
-err := pl.start()
-
-_, err := report.New().
-	From(report.TextReader(os.Stdin)).
-	To(report.TextWriter(os.Stdout)).
-	// FilterBy(report.OrgDomainsFilter).
-	FilterBy(notUsing(report.DomainExtFilter("com", "io"))).
-	GroupBy(report.DomainGrouper).
-	Start()
-*/

27-functional-programming/log-parser-exp/pipeline.go

@@ -1,70 +0,0 @@
-package main
-
-import (
-	"fmt"
-	"os"
-	"time"
-)
-
-type (
-	inputFn  func() ([]result, error)
-	outputFn func([]result) error
-	filterFn func(result) (include bool)
-	groupFn  func(result) (key string)
-)
-
-type pipeline struct {
-	input    inputFn
-	filter   filterFn
-	groupKey groupFn
-	output   outputFn
-}
-
-func newPipeline() *pipeline {
-	return &pipeline{
-		filter:   noopFilter,
-		groupKey: noopGrouper,
-		input:    textReader(os.Stdin),
-		output:   textWriter(os.Stdout),
-	}
-}
-
-func (p *pipeline) from(fn inputFn) *pipeline      { p.input = fn; return p }
-func (p *pipeline) to(fn outputFn) *pipeline       { p.output = fn; return p }
-func (p *pipeline) filterBy(fn filterFn) *pipeline { p.filter = fn; return p }
-func (p *pipeline) groupBy(fn groupFn) *pipeline   { p.groupKey = fn; return p }
-
-func (p *pipeline) start() ([]result, error) {
-	res, err := p.input()
-	if err != nil {
-		return nil, err
-	}
-
-	gres := make(map[string]result)
-
-	for _, r := range res {
-		if !p.filter(r) {
-			continue
-		}
-
-		k := p.groupKey(r)
-		gres[k] = r.add(gres[k])
-	}
-
-	var out []result
-	for _, v := range gres {
-		out = append(out, v)
-	}
-
-	err = p.output(out)
-
-	return out, err
-}
-
-// TODO: remove me
-func measure(name string) func() {
-	start := time.Now()
-	return func() {
-		fmt.Printf("%s took %v\n", name, time.Since(start))
-	}
-}

27-functional-programming/log-parser-exp/result.go

@@ -1,36 +0,0 @@
-package main
-
-import (
-	"fmt"
-)
-
-// result stores the parsed result for a domain
-type result struct {
-	domain  string
-	page    string
-	visits  int
-	uniques int
-}
-
-// parseFields parses and returns the parsing result
-func parseFields(fields []string) (r result, err error) {
-	if len(fields) != 4 {
-		return r, fmt.Errorf("wrong number of fields -> %v", fields)
-	}
-
-	r.domain = fields[0]
-	r.page = fields[1]
-
-	f := new(field)
-	r.visits = f.uatoi("visits", fields[2])
-	r.uniques = f.uatoi("uniques", fields[3])
-
-	return r, f.err
-}
-
-// add adds the metrics of another result to the result
-func (r result) add(other result) result {
-	r.visits += other.visits
-	r.uniques += other.uniques
-	return r
-}

27-functional-programming/log-parser-exp/textreader.go

@@ -1,38 +0,0 @@
-// 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"
-	"io"
-	"strings"
-)
-
-func textReader(r io.Reader) inputFn {
-	return func() ([]result, error) {
-		return parseText(bufio.NewScanner(r))
-	}
-}
-
-// TODO: custom error type for line information
-func parseText(in *bufio.Scanner) ([]result, error) {
-	var res []result
-
-	for l := 1; in.Scan(); l++ {
-		fields := strings.Fields(in.Text())
-		r, err := parseFields(fields)
-
-		if err != nil {
-			return nil, fmt.Errorf("line %d: %v", l, err)
-		}
-		res = append(res, r)
-	}
-
-	return res, in.Err()
-}

27-functional-programming/log-parser-exp/textreaderfast.go

@@ -1,129 +0,0 @@
-// 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"
-	"bytes"
-	"errors"
-	"fmt"
-	"io"
-	"os"
-)
-
-// this could be made faster.
-// currently, it's 30-35% faster.
-//
-// so, what's different than the textreader?
-//
-// + creates the buffers specific to the input file/stdin size
-// + manually parses the fields: instead of strings.Fields
-// + gets the lines using scanner's Bytes() method: instead of Text()
-// + uses a manual atoi
-// +
-
-func fastTextReader(r io.Reader) inputFn {
-	return func() ([]result, error) {
-		// first: count the lines, so the parseText can create
-		// enough buffer.
-		var buf bytes.Buffer
-		l, err := countLines(io.TeeReader(r, &buf))
-		if err != nil {
-			return nil, err
-		}
-
-		return fastParseText(bufio.NewScanner(&buf), l)
-	}
-}
-
-func fastParseText(in *bufio.Scanner, nlines int) ([]result, error) {
-	// needs to know the number of total lines in the file
-	res := make([]result, 0, nlines)
-
-	for l := 0; in.Scan(); l++ {
-		_ = in.Bytes()
-		r, err := fastParseFields(in.Bytes())
-		// r, err := result{"foo.com", "/bar", 10, 10}, error(nil)
-
-		if err != nil {
-			return nil, fmt.Errorf("line %d: %v", l, err)
-		}
-		res = append(res, r)
-	}
-
-	return res, in.Err()
-}
-
-func fastParseFields(data []byte) (res result, err error) {
-	var field int
-
-	for i, last := 0, 0; i < len(data); i++ {
-		done := len(data) == i+1
-
-		if c := data[i]; c == ' ' || done {
-			if done {
-				i = len(data)
-			}
-
-			switch field {
-			case 0:
-				res.domain = string(data[last:i])
-			case 1:
-				res.page = string(data[last:i])
-			case 2:
-				res.visits, err = atoi(data[last:i])
-			case 3:
-				res.uniques, err = atoi(data[last:i])
-			}
-
-			if err != nil {
-				return res, err
-			}
-
-			last = i + 1
-			field++
-		}
-	}
-
-	if field != 4 {
-		return result{}, errors.New("wrong number of fields")
-	}
-	return res, nil
-}
-
-func atoi(input []byte) (int, error) {
-	val := 0
-	for i := 0; i < len(input); i++ {
-		char := input[i]
-		if char < '0' || char > '9' {
-			return 0, errors.New("invalid number")
-		}
-		val = val*10 + int(char) - '0'
-	}
-	return val, nil
-}
-
-func countLines(r io.Reader) (int, error) {
-	var (
-		lines int
-		buf   = make([]byte, os.Getpagesize()) // read via 16 KB blocks
-	)
-
-	for {
-		n, err := r.Read(buf)
-		lines += bytes.Count(buf[:n], []byte{'\n'})
-
-		if err == io.EOF {
-			return lines, nil
-		}
-
-		if err != nil {
-			return lines, err
-		}
-	}
-}

27-functional-programming/log-parser-exp/textwriter.go

@@ -1,43 +0,0 @@
-package main
-
-import (
-	"fmt"
-	"io"
-	"strings"
-)
-
-// TODO: sort by result key interfaces section
-
-const (
-
-	//          DOMAINS PAGES VISITS UNIQUES
-	//             ^      ^     ^    ^
-	//             |      |     |    |
-	header     = "%-25s %-10s %10s %10s\n"
-	line       = "%-25s %-10s %10d %10d\n"
-	footer     = "\n%-36s %10d %10d\n" // -> "" VISITS UNIQUES
-	dashLength = 58
-)
-
-func textWriter(w io.Writer) outputFn {
-	return func(results []result) error {
-		fmt.Fprintf(w, header, "DOMAINS", "PAGES", "VISITS", "UNIQUES")
-		fmt.Fprintln(w, strings.Repeat("-", dashLength))
-
-		var total result
-		for _, r := range results {
-			total = total.add(r)
-			fmt.Fprintf(w, line, r.domain, r.page, r.visits, r.uniques)
-		}
-
-		fmt.Fprintf(w, footer, "", total.visits, total.uniques)
-
-		return nil
-	}
-}
-
-func noWhere() outputFn {
-	return func(res []result) error {
-		return nil
-	}
-}

29-interfaces/logparser-funcs/log.txt

@@ -1,6 +0,0 @@
-learngoprogramming.com 10
-learngoprogramming.com 10
-golang.org 4
-golang.org 6
-blog.golang.org 20
-blog.golang.org 10

29-interfaces/logparser-funcs/log_err_missing.txt

@@ -1,6 +0,0 @@
-learngoprogramming.com 10
-learngoprogramming.com 10
-golang.org
-golang.org 6
-blog.golang.org 20
-blog.golang.org 10

29-interfaces/logparser-funcs/log_err_negative.txt

@@ -1,6 +0,0 @@
-learngoprogramming.com 10
-learngoprogramming.com 10
-golang.org -100
-golang.org 6
-blog.golang.org 20
-blog.golang.org 10

29-interfaces/logparser-funcs/log_err_str.txt

@@ -1,6 +0,0 @@
-learngoprogramming.com 10
-learngoprogramming.com 10
-golang.org FOUR
-golang.org 6
-blog.golang.org 20
-blog.golang.org 10

29-interfaces/logparser-funcs/main.go

@@ -1,26 +0,0 @@
-// 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"
-	"os"
-)
-
-func main() {
-	p := newParser()
-
-	in := bufio.NewScanner(os.Stdin)
-	for in.Scan() {
-		res := parse(p, in.Text())
-		updateSummary(p.summary, res)
-	}
-
-	summarize(summarizeParse(p))
-	dumpErrs(errParse(p), in.Err())
-}

29-interfaces/logparser-funcs/parser.go

@@ -1,70 +0,0 @@
-// 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 (
-	"fmt"
-	"strconv"
-	"strings"
-)
-
-// parser parses the log file and generates a summary report.
-type parser struct {
-	summary *summary // summarizes the parsing results
-	lines   int      // number of parsed lines (for the error messages)
-	lerr    error    // the last error occurred
-}
-
-// new returns a new parsing state.
-func newParser() *parser {
-	return &parser{summary: newSummary()}
-}
-
-// parse parses a log line and adds it to the summary.
-func parse(p *parser, line string) (r result) {
-	// if there was an error do not continue
-	if p.lerr != nil {
-		return
-	}
-
-	// chain the parser's error to the result's
-	r = parseLine(p, line)
-	if p.lines++; p.lerr != nil {
-		p.lerr = fmt.Errorf("line #%d: %s", p.lines, p.lerr)
-	}
-	return
-}
-
-// parse parses a single log line
-func parseLine(p *parser, line string) (r result) {
-	fields := strings.Fields(line)
-	if len(fields) != 2 {
-		// p.lerr = fmt.Errorf("wrong input: %v (line #%d)", fields, p.lines)
-		p.lerr = fmt.Errorf("missing fields: %v", fields)
-		return
-	}
-
-	r.domain = fields[0]
-	r.visits, p.lerr = strconv.Atoi(fields[1])
-
-	if r.visits < 0 || p.lerr != nil {
-		p.lerr = fmt.Errorf("incorrect visits: %q", fields[1])
-	}
-	return
-}
-
-// summarizeParse summarizes the parsing results.
-// Only use it after the parsing is done.
-func summarizeParse(p *parser) *summary {
-	return p.summary
-}
-
-// errParse returns the last error encountered
-func errParse(p *parser) error {
-	return p.lerr
-}

29-interfaces/logparser-funcs/result.go

@@ -1,27 +0,0 @@
-// 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
-
-// always put all the related things together as in here
-
-// result stores metrics for a domain
-// it uses the value mechanics,
-// because it doesn't have to update anything
-type result struct {
-	domain string
-	visits int
-	// add more metrics if needed
-}
-
-// add adds the metrics of another result to itself and returns a new Result
-func addResult(r result, other result) result {
-	return result{
-		domain: r.domain,
-		visits: r.visits + other.visits,
-	}
-}

29-interfaces/logparser-funcs/summarize.go

@@ -1,36 +0,0 @@
-// 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 (
-	"fmt"
-	"strings"
-)
-
-// summarize prints the parsing results.
-func summarize(s *summary) {
-	fmt.Printf("%-30s %10s\n", "DOMAIN", "VISITS")
-	fmt.Println(strings.Repeat("-", 45))
-
-	for next, cur := iteratorSummary(s); next(); {
-		r := cur()
-		fmt.Printf("%-30s %10d\n", r.domain, r.visits)
-	}
-
-	t := totalsSummary(s)
-	fmt.Printf("\n"+"%-30s %10d\n", "TOTAL", t.visits)
-}
-
-// this variadic func simplifies the multiple error handling
-func dumpErrs(errs ...error) {
-	for _, err := range errs {
-		if err != nil {
-			fmt.Printf("> Err: %s\n", err)
-		}
-	}
-}

29-interfaces/logparser-funcs/summary.go

@@ -1,70 +0,0 @@
-// 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 (
-	"sort"
-)
-
-// summary aggregates the parsing results
-type summary struct {
-	sum     map[string]result // metrics per domain
-	domains []string          // unique domain names
-	total   result            // total visits for all domains
-}
-
-// newSummary constructs and initializes a new summary
-// You can't use its methods without pointer mechanics
-func newSummary() *summary {
-	return &summary{sum: make(map[string]result)}
-}
-
-// updateSummary updates the report for the given parsing result
-func updateSummary(s *summary, r result) {
-	domain := r.domain
-	if _, ok := s.sum[domain]; !ok {
-		s.domains = append(s.domains, domain)
-	}
-
-	// let the result handle the addition
-	// this allows us to manage the result in once place
-	// and this way it becomes easily extendable
-	s.total = addResult(s.total, r)
-	s.sum[domain] = addResult(r, s.sum[domain])
-}
-
-// iteratorSummary returns `next()` to detect when the iteration ends,
-// and a `cur()` to return the current result.
-// iterator iterates sorted by domains.
-func iteratorSummary(s *summary) (next func() bool, cur func() result) {
-	sort.Strings(s.domains)
-
-	// remember the last iterated result
-	var last int
-
-	next = func() bool {
-		// done := len(s.domains) > last
-		// last++
-		// return done
-		defer func() { last++ }()
-		return len(s.domains) > last
-	}
-
-	cur = func() result {
-		// returns a copy so the caller cannot change it
-		name := s.domains[last-1]
-		return s.sum[name]
-	}
-
-	return
-}
-
-// totalsSummary returns the total metrics
-func totalsSummary(s *summary) result {
-	return s.total
-}

29-interfaces/logparser-nopkg/log.txt

@@ -1,6 +0,0 @@
-learngoprogramming.com 10 200
-learngoprogramming.com 10 300
-golang.org 4 50
-golang.org 6 100
-blog.golang.org 20 25
-blog.golang.org 10 1

29-interfaces/logparser-nopkg/log_err_missing.txt

@@ -1,6 +0,0 @@
-learngoprogramming.com 10 200
-learngoprogramming.com 10
-golang.org 4 50
-golang.org 6 100
-blog.golang.org 20 25
-blog.golang.org 10 1

29-interfaces/logparser-nopkg/log_err_negative.txt

@@ -1,6 +0,0 @@
-learngoprogramming.com 10 200
-learngoprogramming.com 10 300
-golang.org -100 50
-golang.org 6 100
-blog.golang.org 20 25
-blog.golang.org 10 1

29-interfaces/logparser-nopkg/log_err_str.txt

@@ -1,6 +0,0 @@
-learngoprogramming.com 10 200
-learngoprogramming.com 10 THREE-HUNDRED
-golang.org FOUR 50
-golang.org 6 100
-blog.golang.org 20 25
-blog.golang.org 10 1

29-interfaces/logparser-nopkg/main.go

@@ -1,24 +0,0 @@
-// 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"
-	"os"
-)
-
-func main() {
-	p := newParser()
-
-	in := bufio.NewScanner(os.Stdin)
-	for in.Scan() {
-		p.parse(in.Text())
-	}
-
-	summarize(p.summarize(), p.err(), in.Err())
-}

29-interfaces/logparser-nopkg/parser.go

@@ -1,52 +0,0 @@
-// 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 (
-	"fmt"
-)
-
-// parser parses the log file and generates a summary report.
-type parser struct {
-	summary *summary // summarizes the parsing results
-	lines   int      // number of parsed lines (for the error messages)
-	lerr    error    // the last error occurred
-}
-
-// new returns a new parsing state.
-func newParser() *parser {
-	return &parser{summary: newSummary()}
-}
-
-// parse parses a log line and adds it to the summary.
-func (p *parser) parse(line string) {
-	// if there was an error do not continue
-	if p.lerr != nil {
-		return
-	}
-
-	// chain the parser's error to the result's
-	res, err := parseLine(line)
-	if p.lines++; err != nil {
-		p.lerr = fmt.Errorf("line #%d: %s", p.lines, err)
-		return
-	}
-
-	p.summary.update(res)
-}
-
-// Summarize summarizes the parsing results.
-// Only use it after the parsing is done.
-func (p *parser) summarize() *summary {
-	return p.summary
-}
-
-// Err returns the last error encountered
-func (p *parser) err() error {
-	return p.lerr
-}

29-interfaces/logparser-nopkg/result.go

@@ -1,60 +0,0 @@
-// 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 (
-	"fmt"
-	"strconv"
-	"strings"
-)
-
-// always put all the related things together as in here
-
-// result stores metrics for a domain
-// it uses the value mechanics,
-// because it doesn't have to update anything
-type result struct {
-	domain    string
-	visits    int
-	timeSpent int
-	// add more metrics if needed
-}
-
-// add adds the metrics of another result to itself and returns a new Result
-func (r result) add(other result) result {
-	return result{
-		domain:    r.domain,
-		visits:    r.visits + other.visits,
-		timeSpent: r.timeSpent + other.timeSpent,
-	}
-}
-
-// parse parses a single log line
-func parseLine(line string) (r result, err error) {
-	fields := strings.Fields(line)
-	if len(fields) != 3 {
-		return r, fmt.Errorf("missing fields: %v", fields)
-	}
-
-	f := new(field)
-	r.domain = fields[0]
-	r.visits = f.atoi("visits", fields[1])
-	r.timeSpent = f.atoi("time spent", fields[2])
-	return r, f.err
-}
-
-// field helps for field parsing
-type field struct{ err error }
-
-func (f *field) atoi(name, val string) int {
-	n, err := strconv.Atoi(val)
-	if n < 0 || err != nil {
-		f.err = fmt.Errorf("incorrect %s: %q", name, val)
-	}
-	return n
-}

29-interfaces/logparser-nopkg/summarize.go

@@ -1,51 +0,0 @@
-// 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 (
-	"fmt"
-	"strings"
-)
-
-// summarize prints the parsing results.
-//
-// it prints the errors and returns if there are any.
-//
-// --json flag encodes to json and prints.
-func summarize(sum *summary, errors ...error) {
-	if errs(errors...) {
-		return
-	}
-
-	const (
-		head = "%-30s %10s %20s\n"
-		val  = "%-30s %10d %20d\n"
-	)
-
-	fmt.Printf(head, "DOMAIN", "VISITS", "TIME SPENT")
-	fmt.Println(strings.Repeat("-", 65))
-
-	for next, cur := sum.iterator(); next(); {
-		r := cur()
-		fmt.Printf(val, r.domain, r.visits, r.timeSpent)
-	}
-
-	t := sum.totals()
-	fmt.Printf("\n"+val, "TOTAL", t.visits, t.timeSpent)
-}
-
-// this variadic func simplifies the multiple error handling
-func errs(errs ...error) (wasErr bool) {
-	for _, err := range errs {
-		if err != nil {
-			fmt.Printf("> Err: %s\n", err)
-			wasErr = true
-		}
-	}
-	return
-}

29-interfaces/logparser-nopkg/summary.go

@@ -1,70 +0,0 @@
-// 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 (
-	"sort"
-)
-
-// summary aggregates the parsing results
-type summary struct {
-	sum     map[string]result // metrics per domain
-	domains []string          // unique domain names
-	total   result            // total visits for all domains
-}
-
-// newSummary constructs and initializes a new summary
-// You can't use its methods without pointer mechanics
-func newSummary() *summary {
-	return &summary{sum: make(map[string]result)}
-}
-
-// Update updates the report for the given parsing result
-func (s *summary) update(r result) {
-	domain := r.domain
-	if _, ok := s.sum[domain]; !ok {
-		s.domains = append(s.domains, domain)
-	}
-
-	// let the result handle the addition
-	// this allows us to manage the result in once place
-	// and this way it becomes easily extendable
-	s.total = s.total.add(r)
-	s.sum[domain] = r.add(s.sum[domain])
-}
-
-// Iterator returns `next()` to detect when the iteration ends,
-// and a `cur()` to return the current result.
-// iterator iterates sorted by domains.
-func (s *summary) iterator() (next func() bool, cur func() result) {
-	sort.Strings(s.domains)
-
-	// remember the last iterated result
-	var last int
-
-	next = func() bool {
-		// done := len(s.domains) > last
-		// last++
-		// return done
-		defer func() { last++ }()
-		return len(s.domains) > last
-	}
-
-	cur = func() result {
-		// returns a copy so the caller cannot change it
-		name := s.domains[last-1]
-		return s.sum[name]
-	}
-
-	return
-}
-
-// totals returns the total metrics
-func (s *summary) totals() result {
-	return s.total
-}

29-interfaces/logparser-pkg/log.txt

@@ -1,6 +0,0 @@
-learngoprogramming.com 10 200
-learngoprogramming.com 10 300
-golang.org 4 50
-golang.org 6 100
-blog.golang.org 20 25
-blog.golang.org 10 1

29-interfaces/logparser-pkg/log_err_missing.txt

@@ -1,6 +0,0 @@
-learngoprogramming.com 10 200
-learngoprogramming.com 10
-golang.org 4 50
-golang.org 6 100
-blog.golang.org 20 25
-blog.golang.org 10 1

29-interfaces/logparser-pkg/log_err_negative.txt

@@ -1,6 +0,0 @@
-learngoprogramming.com 10 200
-learngoprogramming.com 10 300
-golang.org -100 50
-golang.org 6 100
-blog.golang.org 20 25
-blog.golang.org 10 1

29-interfaces/logparser-pkg/log_err_str.txt

@@ -1,6 +0,0 @@
-learngoprogramming.com 10 200
-learngoprogramming.com 10 THREE-HUNDRED
-golang.org FOUR 50
-golang.org 6 100
-blog.golang.org 20 25
-blog.golang.org 10 1

29-interfaces/logparser-pkg/main.go

@@ -1,26 +0,0 @@
-// 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"
-	"os"
-
-	"github.com/inancgumus/learngo/29-interfaces/logparser-pkg/report"
-)
-
-func main() {
-	p := report.New()
-
-	in := bufio.NewScanner(os.Stdin)
-	for in.Scan() {
-		p.Parse(in.Text())
-	}
-
-	summarize(p.Summarize(), p.Err(), in.Err())
-}

29-interfaces/logparser-pkg/report/parser.go

@@ -1,52 +0,0 @@
-// 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 report
-
-import (
-	"fmt"
-)
-
-// Parser parses the log file and generates a summary report.
-type Parser struct {
-	summary *Summary // summarizes the parsing results
-	lines   int      // number of parsed lines (for the error messages)
-	lerr    error    // the last error occurred
-}
-
-// New returns a new parsing state.
-func New() *Parser {
-	return &Parser{summary: newSummary()}
-}
-
-// Parse parses a log line and adds it to the summary.
-func (p *Parser) Parse(line string) {
-	// if there was an error do not continue
-	if p.lerr != nil {
-		return
-	}
-
-	// chain the parser's error to the result's
-	res, err := parse(line)
-	if p.lines++; err != nil {
-		p.lerr = fmt.Errorf("line #%d: %s", p.lines, err)
-		return
-	}
-
-	p.summary.update(res)
-}
-
-// Summarize summarizes the parsing results.
-// Only use it after the parsing is done.
-func (p *Parser) Summarize() *Summary {
-	return p.summary
-}
-
-// Err returns the last error encountered
-func (p *Parser) Err() error {
-	return p.lerr
-}

29-interfaces/logparser-pkg/report/result.go

@@ -1,60 +0,0 @@
-// 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 report
-
-import (
-	"fmt"
-	"strconv"
-	"strings"
-)
-
-// always put all the related things together as in here
-
-// Result stores metrics for a domain
-// it uses the value mechanics,
-// because it doesn't have to update anything
-type Result struct {
-	Domain    string `json:"domain"`
-	Visits    int    `json:"visits"`
-	TimeSpent int    `json:"time_spent"`
-	// add more metrics if needed
-}
-
-// add adds the metrics of another Result to itself and returns a new Result
-func (r Result) add(other Result) Result {
-	return Result{
-		Domain:    r.Domain,
-		Visits:    r.Visits + other.Visits,
-		TimeSpent: r.TimeSpent + other.TimeSpent,
-	}
-}
-
-// parse parses a single log line
-func parse(line string) (r Result, err error) {
-	fields := strings.Fields(line)
-	if len(fields) != 3 {
-		return r, fmt.Errorf("missing fields: %v", fields)
-	}
-
-	f := new(field)
-	r.Domain = fields[0]
-	r.Visits = f.atoi("visits", fields[1])
-	r.TimeSpent = f.atoi("time spent", fields[2])
-	return r, f.err
-}
-
-// field helps for field parsing
-type field struct{ err error }
-
-func (f *field) atoi(name, val string) int {
-	n, err := strconv.Atoi(val)
-	if n < 0 || err != nil {
-		f.err = fmt.Errorf("incorrect %s: %q", name, val)
-	}
-	return n
-}

29-interfaces/logparser-pkg/report/summary.go

@@ -1,85 +0,0 @@
-// 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 report
-
-import (
-	"encoding/json"
-	"sort"
-)
-
-// Summary aggregates the parsing results
-type Summary struct {
-	sum     map[string]Result // metrics per domain
-	domains []string          // unique domain names
-	total   Result            // total visits for all domains
-}
-
-// newSummary constructs and initializes a new summary
-// You can't use its methods without pointer mechanics
-func newSummary() *Summary {
-	return &Summary{sum: make(map[string]Result)}
-}
-
-// Update updates the report for the given parsing result
-func (s *Summary) update(r Result) {
-	domain := r.Domain
-	if _, ok := s.sum[domain]; !ok {
-		s.domains = append(s.domains, domain)
-	}
-
-	// let the result handle the addition
-	// this allows us to manage the result in once place
-	// and this way it becomes easily extendable
-	s.total = s.total.add(r)
-	s.sum[domain] = r.add(s.sum[domain])
-}
-
-// Iterator returns `next()` to detect when the iteration ends,
-// and a `cur()` to return the current result.
-// iterator iterates sorted by domains.
-func (s *Summary) Iterator() (next func() bool, cur func() Result) {
-	sort.Strings(s.domains)
-
-	// remember the last iterated result
-	var last int
-
-	next = func() bool {
-		defer func() { last++ }()
-		return len(s.domains) > last
-	}
-
-	cur = func() Result {
-		// returns a copy so the caller cannot change it
-		name := s.domains[last-1]
-		return s.sum[name]
-	}
-
-	return
-}
-
-// Total returns the total metrics
-func (s *Summary) Total() Result {
-	return s.total
-}
-
-// MarshalJSON marshals a report to JSON
-// Alternative: unexported embedding
-func (s *Summary) MarshalJSON() ([]byte, error) {
-	type total struct {
-		*Result
-		IgnoreDomain *string `json:"domain,omitempty"`
-	}
-
-	return json.Marshal(struct {
-		Sum     map[string]Result `json:"summary"`
-		Domains []string          `json:"domains"`
-		Total   total             `json:"total"`
-	}{
-		Sum: s.sum, Domains: s.domains, Total: total{Result: &s.total},
-	})
-}

29-interfaces/logparser-pkg/summarize.go

@@ -1,73 +0,0 @@
-// 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 (
-	"encoding/json"
-	"fmt"
-	"os"
-	"strings"
-
-	"github.com/inancgumus/learngo/29-interfaces/logparser-pkg/report"
-)
-
-// summarize prints the parsing results.
-//
-// it prints the errors and returns if there are any.
-//
-// --json flag encodes to json and prints.
-func summarize(sum *report.Summary, errors ...error) {
-	if errs(errors...) {
-		return
-	}
-
-	if args := os.Args[1:]; len(args) == 1 && args[0] == "--json" {
-		encode(sum)
-		return
-	}
-	stdout(sum)
-}
-
-// encodes the summary to json
-func encode(sum *report.Summary) {
-	out, err := json.MarshalIndent(sum, "", "\t")
-	if err != nil {
-		panic(err)
-	}
-	os.Stdout.Write(out)
-}
-
-// prints the summary to standard out
-func stdout(sum *report.Summary) {
-	const (
-		head = "%-30s %10s %20s\n"
-		val  = "%-30s %10d %20d\n"
-	)
-
-	fmt.Printf(head, "DOMAIN", "VISITS", "TIME SPENT")
-	fmt.Println(strings.Repeat("-", 65))
-
-	for next, cur := sum.Iterator(); next(); {
-		r := cur()
-		fmt.Printf(val, r.Domain, r.Visits, r.TimeSpent)
-	}
-
-	t := sum.Total()
-	fmt.Printf("\n"+val, "TOTAL", t.Visits, t.TimeSpent)
-}
-
-// this variadic func simplifies the multiple error handling
-func errs(errs ...error) (wasErr bool) {
-	for _, err := range errs {
-		if err != nil {
-			fmt.Printf("> Err: %s\n", err)
-			wasErr = true
-		}
-	}
-	return
-}

29-interfaces/logparser-testing/log.txt

@@ -1,6 +0,0 @@
-learngoprogramming.com 10 200
-learngoprogramming.com 10 300
-golang.org 4 50
-golang.org 6 100
-blog.golang.org 20 25
-blog.golang.org 10 1

29-interfaces/logparser-testing/log_err_missing.txt

@@ -1,6 +0,0 @@
-learngoprogramming.com 10 200
-learngoprogramming.com 10
-golang.org 4 50
-golang.org 6 100
-blog.golang.org 20 25
-blog.golang.org 10 1

29-interfaces/logparser-testing/log_err_negative.txt

@@ -1,6 +0,0 @@
-learngoprogramming.com 10 200
-learngoprogramming.com 10 300
-golang.org -100 50
-golang.org 6 100
-blog.golang.org 20 25
-blog.golang.org 10 1

29-interfaces/logparser-testing/log_err_str.txt

@@ -1,6 +0,0 @@
-learngoprogramming.com 10 200
-learngoprogramming.com 10 THREE-HUNDRED
-golang.org FOUR 50
-golang.org 6 100
-blog.golang.org 20 25
-blog.golang.org 10 1

29-interfaces/logparser-testing/main.go

@@ -1,26 +0,0 @@
-// 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"
-	"os"
-
-	"github.com/inancgumus/learngo/29-interfaces/logparser-testing/report"
-)
-
-func main() {
-	p := report.New()
-
-	in := bufio.NewScanner(os.Stdin)
-	for in.Scan() {
-		p.Parse(in.Text())
-	}
-
-	summarize(p.Summarize(), p.Err(), in.Err())
-}

29-interfaces/logparser-testing/main_test.go

@@ -1,59 +0,0 @@
-// +build integration
-
-// go test -tags=integration
-
-package main_test
-
-import (
-	"bytes"
-	"os/exec"
-	"strings"
-	"testing"
-)
-
-const (
-	okIn = `
-a.com 1 2
-b.com 3 4
-a.com 4 5
-b.com 6 7`
-
-	okOut = `
-DOMAIN                             VISITS           TIME SPENT
------------------------------------------------------------------
-a.com                                   5                    7
-b.com                                   9                   11
-
-TOTAL                                  14                   18`
-)
-
-func TestSummary(t *testing.T) {
-	tests := []struct {
-		name, in, out string
-	}{
-		{"valid input", okIn, okOut},
-		{"missing fields", "a.com 1 2\nb.com 3", "> Err: line #2: missing fields: [b.com 3]"},
-		{"incorrect visits", "a.com 1 2\nb.com -1 1", `> Err: line #2: incorrect visits: "-1"`},
-		{"incorrect time spent", "a.com 1 2\nb.com 3 -1", `> Err: line #2: incorrect time spent: "-1"`},
-	}
-
-	for _, tt := range tests {
-		t.Run(tt.name, func(t *testing.T) {
-			run(t, strings.TrimSpace(tt.in), strings.TrimSpace(tt.out))
-		})
-	}
-}
-
-func run(t *testing.T, in, out string) {
-	cmd := exec.Command("go", "run", ".")
-	cmd.Stdin = strings.NewReader(in)
-
-	got, err := cmd.CombinedOutput()
-	if err != nil {
-		t.Fatal(err)
-	}
-
-	if !bytes.Equal(got, []byte(out+"\n")) {
-		t.Fatalf("\nwant:\n%s\n\ngot:\n%s", out, got)
-	}
-}

29-interfaces/logparser-testing/report/parser.go

@@ -1,52 +0,0 @@
-// 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 report
-
-import (
-	"fmt"
-)
-
-// Parser parses the log file and generates a summary report.
-type Parser struct {
-	summary *Summary // summarizes the parsing results
-	lines   int      // number of parsed lines (for the error messages)
-	lerr    error    // the last error occurred
-}
-
-// New returns a new parsing state.
-func New() *Parser {
-	return &Parser{summary: newSummary()}
-}
-
-// Parse parses a log line and adds it to the summary.
-func (p *Parser) Parse(line string) {
-	// if there was an error do not continue
-	if p.lerr != nil {
-		return
-	}
-
-	// chain the parser's error to the result's
-	res, err := parse(line)
-	if p.lines++; err != nil {
-		p.lerr = fmt.Errorf("line #%d: %s", p.lines, err)
-		return
-	}
-
-	p.summary.update(res)
-}
-
-// Summarize summarizes the parsing results.
-// Only use it after the parsing is done.
-func (p *Parser) Summarize() *Summary {
-	return p.summary
-}
-
-// Err returns the last error encountered
-func (p *Parser) Err() error {
-	return p.lerr
-}

29-interfaces/logparser-testing/report/parser_test.go

@@ -1,55 +0,0 @@
-package report_test
-
-import (
-	"strings"
-	"testing"
-
-	"github.com/inancgumus/learngo/28-methods/logparser-testing/report"
-)
-
-func newParser(lines string) *report.Parser {
-	p := report.New()
-	p.Parse(lines)
-	return p
-}
-
-func TestParserLineErrs(t *testing.T) {
-	p := newParser("a.com 1 2")
-	p.Parse("b.com -1 -1")
-
-	want := "#2"
-	err := p.Err().Error()
-
-	if !strings.Contains(err, want) {
-		t.Errorf("want: %q; got: %q", want, err)
-	}
-}
-
-func TestParserStopsOnErr(t *testing.T) {
-	p := newParser("a.com 10 20")
-	p.Parse("b.com -1 -1")
-	p.Parse("neverparses.com 30 40")
-
-	s := p.Summarize()
-	if want, got := 10, s.Total().Visits; want != got {
-		t.Errorf("want: %d; got: %d", want, got)
-	}
-}
-
-func TestParserIncorrectFields(t *testing.T) {
-	tests := []struct {
-		in, name string
-	}{
-		{"a.com", "missing fields"},
-		{"a.com -1 2", "incorrect visits"},
-		{"a.com 1 -1", "incorrect time spent"},
-	}
-
-	for _, tt := range tests {
-		t.Run(tt.name, func(t *testing.T) {
-			if p := newParser(tt.in); p.Err() == nil {
-				t.Errorf("in: %q; got: nil err", tt.in)
-			}
-		})
-	}
-}

29-interfaces/logparser-testing/report/result.go

@@ -1,60 +0,0 @@
-// 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 report
-
-import (
-	"fmt"
-	"strconv"
-	"strings"
-)
-
-// always put all the related things together as in here
-
-// Result stores metrics for a domain
-// it uses the value mechanics,
-// because it doesn't have to update anything
-type Result struct {
-	Domain    string `json:"domain"`
-	Visits    int    `json:"visits"`
-	TimeSpent int    `json:"time_spent"`
-	// add more metrics if needed
-}
-
-// add adds the metrics of another Result to itself and returns a new Result
-func (r Result) add(other Result) Result {
-	return Result{
-		Domain:    r.Domain,
-		Visits:    r.Visits + other.Visits,
-		TimeSpent: r.TimeSpent + other.TimeSpent,
-	}
-}
-
-// parse parses a single log line
-func parse(line string) (r Result, err error) {
-	fields := strings.Fields(line)
-	if len(fields) != 3 {
-		return r, fmt.Errorf("missing fields: %v", fields)
-	}
-
-	f := new(field)
-	r.Domain = fields[0]
-	r.Visits = f.atoi("visits", fields[1])
-	r.TimeSpent = f.atoi("time spent", fields[2])
-	return r, f.err
-}
-
-// field helps for field parsing
-type field struct{ err error }
-
-func (f *field) atoi(name, val string) int {
-	n, err := strconv.Atoi(val)
-	if n < 0 || err != nil {
-		f.err = fmt.Errorf("incorrect %s: %q", name, val)
-	}
-	return n
-}

29-interfaces/logparser-testing/report/summary.go

@@ -1,86 +0,0 @@
-// 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 report
-
-import (
-	"sort"
-)
-
-// Summary aggregates the parsing results
-type Summary struct {
-	sum     map[string]Result // metrics per domain
-	domains []string          // unique domain names
-	total   Result            // total visits for all domains
-}
-
-// newSummary constructs and initializes a new summary
-// You can't use its methods without pointer mechanics
-func newSummary() *Summary {
-	return &Summary{sum: make(map[string]Result)}
-}
-
-// Update updates the report for the given parsing result
-func (s *Summary) update(r Result) {
-	domain := r.Domain
-	if _, ok := s.sum[domain]; !ok {
-		s.domains = append(s.domains, domain)
-	}
-
-	// let the result handle the addition
-	// this allows us to manage the result in once place
-	// and this way it becomes easily extendable
-	s.total = s.total.add(r)
-	s.sum[domain] = r.add(s.sum[domain])
-}
-
-// Iterator returns `next()` to detect when the iteration ends,
-// and a `cur()` to return the current result.
-// iterator iterates sorted by domains.
-func (s *Summary) Iterator() (next func() bool, cur func() Result) {
-	sort.Strings(s.domains)
-
-	// remember the last iterated result
-	var last int
-
-	next = func() bool {
-		defer func() { last++ }()
-		return len(s.domains) > last
-	}
-
-	cur = func() Result {
-		// returns a copy so the caller cannot change it
-		name := s.domains[last-1]
-		return s.sum[name]
-	}
-
-	return
-}
-
-// Total returns the total metrics
-func (s *Summary) Total() Result {
-	return s.total
-}
-
-// For the interfaces section
-//
-// MarshalJSON marshals a report to JSON
-// Alternative: unexported embedding
-// func (s *Summary) MarshalJSON() ([]byte, error) {
-// 	type total struct {
-// 		*Result
-// 		IgnoreDomain *string `json:"domain,omitempty"`
-// 	}
-
-// 	return json.Marshal(struct {
-// 		Sum     map[string]Result `json:"summary"`
-// 		Domains []string          `json:"domains"`
-// 		Total   total             `json:"total"`
-// 	}{
-// 		Sum: s.sum, Domains: s.domains, Total: total{Result: &s.total},
-// 	})
-// }

29-interfaces/logparser-testing/report/summary_test.go

@@ -1,44 +0,0 @@
-package report_test
-
-import (
-	"testing"
-
-	"github.com/inancgumus/learngo/28-methods/logparser-testing/report"
-)
-
-func TestSummaryTotal(t *testing.T) {
-	p := newParser("a.com 1 2")
-	p.Parse("b.com 3 4")
-
-	s := p.Summarize()
-
-	want := report.Result{Domain: "", Visits: 4, TimeSpent: 6}
-	if got := s.Total(); want != got {
-		t.Errorf("want: %+v; got: %+v", want, got)
-	}
-}
-
-func TestSummaryIterator(t *testing.T) {
-	p := newParser("a.com 1 2")
-	p.Parse("a.com 3 4")
-	p.Parse("b.com 5 6")
-
-	s := p.Summarize()
-	next, cur := s.Iterator()
-
-	wants := []report.Result{
-		{Domain: "a.com", Visits: 4, TimeSpent: 6},
-		{Domain: "b.com", Visits: 5, TimeSpent: 6},
-	}
-
-	for _, want := range wants {
-		t.Run(want.Domain, func(t *testing.T) {
-			if got := next(); !got {
-				t.Errorf("next(): want: %t; got: %t", true, got)
-			}
-			if got := cur(); want != got {
-				t.Errorf("cur(): want: %+v; got: %+v", want, got)
-			}
-		})
-	}
-}

29-interfaces/logparser-testing/summarize.go

@@ -1,73 +0,0 @@
-// 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 (
-	"encoding/json"
-	"fmt"
-	"os"
-	"strings"
-
-	"github.com/inancgumus/learngo/29-interfaces/logparser-testing/report"
-)
-
-// summarize prints the parsing results.
-//
-// it prints the errors and returns if there are any.
-//
-// --json flag encodes to json and prints.
-func summarize(sum *report.Summary, errors ...error) {
-	if errs(errors...) {
-		return
-	}
-
-	if args := os.Args[1:]; len(args) == 1 && args[0] == "--json" {
-		encode(sum)
-		return
-	}
-	stdout(sum)
-}
-
-// encodes the summary to json
-func encode(sum *report.Summary) {
-	out, err := json.MarshalIndent(sum, "", "\t")
-	if err != nil {
-		panic(err)
-	}
-	os.Stdout.Write(out)
-}
-
-// prints the summary to standard out
-func stdout(sum *report.Summary) {
-	const (
-		head = "%-30s %10s %20s\n"
-		val  = "%-30s %10d %20d\n"
-	)
-
-	fmt.Printf(head, "DOMAIN", "VISITS", "TIME SPENT")
-	fmt.Println(strings.Repeat("-", 65))
-
-	for next, cur := sum.Iterator(); next(); {
-		r := cur()
-		fmt.Printf(val, r.Domain, r.Visits, r.TimeSpent)
-	}
-
-	t := sum.Total()
-	fmt.Printf("\n"+val, "TOTAL", t.Visits, t.TimeSpent)
-}
-
-// this variadic func simplifies the multiple error handling
-func errs(errs ...error) (wasErr bool) {
-	for _, err := range errs {
-		if err != nil {
-			fmt.Printf("> Err: %s\n", err)
-			wasErr = true
-		}
-	}
-	return
-}