Initial

.gitignore

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+.idea

Readme.md

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+# todo.txt Go parser
+
+Simple parser for [todo.txt](http://todotxt.org/) file format.
+
+[Documentation](https://godoc.org/github.com/neonxp/go-todo.txt)

go.mod

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+module todotxt
+
+go 1.12

todotxt.go

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+package todotxt
+
+import (
+	"errors"
+	"fmt"
+	"strings"
+	"time"
+)
+
+// Item represents todotxt task
+type Item struct {
+	Complete       bool
+	Priority       *Priority
+	CompletionDate *time.Time
+	CreationDate   *time.Time
+	Description    string
+	Tags           []Tag
+}
+
+// String returns text representation of Item
+func (i *Item) String() string {
+	result := ""
+	if i.Complete {
+		result = "x "
+	}
+	if i.Priority != nil {
+		result += "(" + i.Priority.String() + ") "
+	}
+
+	if i.CompletionDate != nil {
+		result += i.CompletionDate.Format("2006-01-02") + " "
+		if i.CreationDate != nil {
+			result += i.CreationDate.Format("2006-01-02") + " "
+		} else {
+			result += time.Now().Format("2006-01-02") + " "
+		}
+	} else if i.CreationDate != nil {
+		result += i.CreationDate.Format("2006-01-02") + " "
+	}
+	result += i.Description + " "
+	for _, t := range i.Tags {
+		switch t.Key {
+		case TagContext:
+			result += "@" + t.Value + " "
+		case TagProject:
+			result += "+" + t.Value + " "
+		default:
+			result += t.Key + ":" + t.Value + " "
+		}
+	}
+	return strings.Trim(result, " \n")
+}
+
+// Parse multiline todotxt string
+func Parse(todo string) ([]Item, error) {
+	lines := strings.Split(todo, "\n")
+	items := make([]Item, 0, len(lines))
+	for ln, line := range lines {
+		i, err := ParseLine(line)
+		if err != nil {
+			return nil, fmt.Errorf("error at line %d: %v", ln, err)
+		}
+		items = append(items, i)
+	}
+	return items, nil
+}
+
+// ParseLine parses single todotxt line
+func ParseLine(line string) (Item, error) {
+	i := Item{}
+	tokens := strings.Split(line, " ")
+	state := 0
+	for _, t := range tokens {
+		if state == 0 && t == "x" {
+			state = 1
+			i.Complete = true
+			continue
+		}
+		if state <= 1 && len(t) == 3 && t[0] == '(' && t[2] == ')' {
+			p, err := PriorityFromLetter(string(t[1]))
+			if err != nil {
+				return i, err
+			}
+			i.Priority = &p
+			state = 2
+			continue
+		}
+		if state <= 2 {
+			ti, err := time.Parse("2006-01-02", t)
+			if err == nil {
+				i.CreationDate = &ti
+				state = 3
+				continue
+			}
+			state = 4
+		}
+		if state <= 3 {
+			ti, err := time.Parse("2006-01-02", t)
+			if err == nil {
+				i.CompletionDate = i.CreationDate
+				i.CreationDate = &ti
+				state = 4
+				continue
+			}
+			state = 4
+		}
+		if t[0] == '+' {
+			i.Tags = append(i.Tags, Tag{
+				Key:   TagProject,
+				Value: string(t[1:]),
+			})
+			continue
+		}
+		if t[0] == '@' {
+			i.Tags = append(i.Tags, Tag{
+				Key:   TagContext,
+				Value: string(t[1:]),
+			})
+			continue
+		}
+		kv := strings.Split(t, ":")
+		if len(kv) == 2 {
+			i.Tags = append(i.Tags, Tag{
+				Key:   kv[0],
+				Value: kv[1],
+			})
+			continue
+		}
+		if i.Description == "" {
+			i.Description = t
+		} else {
+			i.Description += " " + t
+		}
+	}
+	return i, nil
+}
+
+type Priority int
+
+// String returns letter by priority (0=A, 1=B, 2=C ...)
+func (p Priority) String() string {
+	return string([]byte{byte(p + 65)})
+}
+
+// PriorityFromLetter returns numeric priority from letter priority (A=0, B=1, C=2 ...)
+func PriorityFromLetter(letter string) (Priority, error) {
+	if len(letter) != 1 {
+		return 0, errors.New("incorrect priority length")
+	}
+	code := []byte(letter)[0]
+	if code < 65 || code > 90 {
+		return 0, errors.New("priority must be between A and Z")
+	}
+	return Priority(code - 65), nil
+}
+
+// TagContext constant is key for context tag
+const TagContext = "@context"
+
+// TagProject constant is key for project tag
+const TagProject = "+project"
+
+// Tag represents builtin and custom tags
+type Tag struct {
+	Key   string
+	Value string
+}

todotxt_test.go

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+package todotxt
+
+import (
+	"strings"
+	"testing"
+	"time"
+)
+
+func TestPriorityFromLetter(t *testing.T) {
+	tests := []struct {
+		letter        string
+		expectedError bool
+		expectedVal   int
+	}{
+		{"A", false, 0},
+		{"B", false, 1},
+		{"Z", false, 25},
+		{"a", true, 0},
+		{"AA", true, 0},
+		{"0", true, 0},
+		{"!", true, 0},
+	}
+	for i, test := range tests {
+		p, err := PriorityFromLetter(test.letter)
+		if test.expectedError && err == nil {
+			t.Errorf("expected error on test %d", i+1)
+		}
+		if !test.expectedError && err != nil {
+			t.Errorf("unexpected error on test %d: %v", i+1, err)
+		}
+		if p != Priority(test.expectedVal) {
+			t.Errorf("expected %d, got %d on test %d", test.expectedVal, p, i+1)
+		}
+	}
+}
+
+func TestPriorityToString(t *testing.T) {
+	a, _ := PriorityFromLetter("A")
+	z, _ := PriorityFromLetter("Z")
+	if a.String() != "A" {
+		t.Errorf("Expected A, got %s", a.String())
+	}
+	if z.String() != "Z" {
+		t.Errorf("Expected Z, got %s", z.String())
+	}
+}
+
+func TestItemToString(t *testing.T) {
+	cd, _ := time.Parse("2006-01-02", "2019-04-27")
+	tests := map[string]struct {
+		item     Item
+		expected string
+	}{
+		"simple":           {item: Item{Description: "simple"}, expected: "simple"},
+		"complete":         {item: Item{Complete: true, Description: "complete"}, expected: "x complete"},
+		"completeWithDate": {item: Item{Complete: true, CreationDate: &cd, Description: "complete"}, expected: "x 2019-04-27 complete"},
+		"completeWithTags": {item: Item{Complete: true, Description: "complete", Tags: []Tag{{Key: TagProject, Value: "proj"}, {Key: TagContext, Value: "test"}, {Key: "custom", Value: "tag"}}}, expected: "x complete +proj @test custom:tag"},
+	}
+	for test, v := range tests {
+		t.Run(test, func(t *testing.T) {
+			if v.item.String() != v.expected {
+				t.Errorf("Expected %s got %s", v.expected, v.item.String())
+			}
+		})
+	}
+}
+
+func TestParse(t *testing.T) {
+	input := `(A) Call Mom @Phone +Family
+(A) Schedule annual checkup +Health
+(B) Outline chapter 5 +Novel @Computer
+(C) Add cover sheets @Office +TPSReports
+2019-04-27 Plan backyard herb garden @Home
+2019-05-27 2019-04-27 Pick up milk @GroceryStore
+Research self-publishing services +Novel @Computer
+x Download Todo.txt mobile app @Phone custom:tag`
+	items, err := Parse(input)
+	if err != nil {
+		t.Error(err)
+	}
+	for ln, v := range items {
+		if strings.Split(input, "\n")[ln] != v.String() {
+			t.Logf("line %d expected %s got %s", ln, strings.Split(input, "\n")[ln], v.String())
+		}
+	}
+}