Added a comment

internal/oviewer/content.go

@@ -55,7 +55,7 @@ func parseString(line string, tabWidth int) lineContents {
 	style := tcell.StyleDefault
 	x := 0
 	n := 0
-	bsFlag := false
+	bsFlag := false // backspace(^H) flag
 	var bsContent Content
 	for _, runeValue := range line {
 		c := DefaultContent
@@ -181,6 +181,7 @@ func parseString(line string, tabWidth int) lineContents {
 	return lc
 }
 
+// overstrike returns an overstrike tcell.Style.
 func overstrike(p, m rune, style tcell.Style) tcell.Style {
 	if p == m {
 		style = OverStrikeStyle
@@ -190,6 +191,7 @@ func overstrike(p, m rune, style tcell.Style) tcell.Style {
 	return style
 }
 
+// lastContent returns the last character of Contents.
 func lastContent(contents []Content) Content {
 	n := len(contents)
 	if n == 0 {
@@ -201,6 +203,7 @@ func lastContent(contents []Content) Content {
 	return contents[n-1]
 }
 
+// csToStyle returns tcell.Style from the control sequence.
 func csToStyle(style tcell.Style, csiParameter *bytes.Buffer) tcell.Style {
 	fields := strings.Split(csiParameter.String(), ";")
 	if len(fields) == 0 || len(fields) == 1 && fields[0] == "0" {
@@ -275,6 +278,7 @@ FieldLoop:
 	return style
 }
 
+// lookupColor returns the color name from the color number.
 func lookupColor(colorNumber int) string {
 	if colorNumber < 0 || colorNumber > 15 {
 		return "black"

internal/oviewer/input.go

@@ -131,6 +131,7 @@ func (root *Root) inputKeyEvent(ev *tcell.EventKey) bool {
 	return false
 }
 
+// stringWidth returns the number of characters in the input.
 func stringWidth(str string, cursor int) int {
 	width := 0
 	i := 0
@@ -147,6 +148,7 @@ func stringWidth(str string, cursor int) int {
 	return i
 }
 
+// runeWidth returns the number of widths of the input.
 func runeWidth(str string) int {
 	width := 0
 	for _, r := range str {

internal/oviewer/model.go

@@ -9,20 +9,31 @@ import (
 // The Model structure contains the values
 // for the logical screen.
 type Model struct {
-	// updated by reader goroutine
+	// buffer stores the contents of the file in slices of strings.
+	// buffer,endNum and eof is updated by reader goroutine.
 	buffer []string
+	// endNum is the number of the last line read.
 	endNum int
-	eof    bool
-
-	x          int
-	lineNum    int
-	yy         int
-	header     []string
+	// eof is or has reached EOF.
+	eof bool
+
+	// x is the starting position of the current x.
+	x int
+	// lineNum is the starting position of the current y.
+	lineNum int
+	// yy represents the number of wrapped lines.
+	yy int
+	// header represents the header line.
+	header []string
+	// beforeSize represents the number of lines to read first.
 	beforeSize int
-	vWidth     int
-	vHight     int
-	cache      *ristretto.Cache
-
+	// vWidth represents the screen width.
+	vWidth int
+	// vHight represents the screen height.
+	vHight int
+	// cache represents a cache of contents.
+	cache *ristretto.Cache
+	// mu controls the mutex.
 	mu sync.Mutex
 }
 
@@ -94,6 +105,7 @@ func (m *Model) GetContents(lineNum int, tabWidth int) []Content {
 	return lc.contents
 }
 
+// lineToContents returns contents from line number.
 func (m *Model) lineToContents(lineNum int, tabWidth int) (lineContents, error) {
 	var lc lineContents
 

internal/oviewer/oviewer.go

@@ -117,15 +117,6 @@ func New() *Root {
 	return root
 }
 
-// PrepareView prepares when the screen size is changed.
-func (root *Root) PrepareView() {
-	m := root.Model
-	screen := root.Screen
-	m.vWidth, m.vHight = screen.Size()
-	root.setWrapHeaderLen()
-	root.statusPos = m.vHight - 1
-}
-
 // Run is reads the file(or stdin) and starts
 // the terminal pager.
 func (root *Root) Run(args []string) error {
@@ -203,6 +194,45 @@ func (root *Root) Run(args []string) error {
 	return nil
 }
 
+// main is manages and executes events in the main routine.
+func (root *Root) main() {
+	screen := root.Screen
+	go root.countTimer()
+
+loop:
+	for {
+		root.Draw()
+		ev := screen.PollEvent()
+		switch ev := ev.(type) {
+		case *eventTimer:
+			root.updateEndNum()
+		case *eventAppQuit:
+			break loop
+		case *SearchInput:
+			root.Search(root.Input.value)
+		case *BackSearchInput:
+			root.BackSearch(root.Input.value)
+		case *GotoInput:
+			root.GoLine(root.Input.value)
+		case *HeaderInput:
+			root.SetHeader(root.Input.value)
+		case *DelimiterInput:
+			root.SetDelimiter(root.Input.value)
+		case *TABWidthInput:
+			root.SetTabWidth(root.Input.value)
+		case *tcell.EventKey:
+			root.message = ""
+			if root.Input.mode == normal {
+				root.DefaultKeyEvent(ev)
+			} else {
+				root.InputKeyEvent(ev)
+			}
+		case *tcell.EventResize:
+			root.Resize()
+		}
+	}
+}
+
 // setGlobalStyle sets some styles that are determined by the settings.
 func (root *Root) setGlobalStyle() {
 	if root.ColorAlternate != "" {
@@ -219,6 +249,15 @@ func (root *Root) setGlobalStyle() {
 	}
 }
 
+// PrepareView prepares when the screen size is changed.
+func (root *Root) PrepareView() {
+	m := root.Model
+	screen := root.Screen
+	m.vWidth, m.vHight = screen.Size()
+	root.setWrapHeaderLen()
+	root.statusPos = m.vHight - 1
+}
+
 // contentsSmall returns with bool whether the file to display fits on the screen.
 func (root *Root) contentsSmall() bool {
 	root.PrepareView()
@@ -368,53 +407,14 @@ func (root *Root) updateEndNum() {
 	root.statusDraw()
 }
 
-// main is manages and executes events in the main routine.
-func (root *Root) main() {
-	screen := root.Screen
-	go root.countTimer()
-
-loop:
-	for {
-		root.Draw()
-		ev := screen.PollEvent()
-		switch ev := ev.(type) {
-		case *eventTimer:
-			root.updateEndNum()
-		case *eventAppQuit:
-			break loop
-		case *SearchInput:
-			root.Search(root.Input.value)
-		case *BackSearchInput:
-			root.BackSearch(root.Input.value)
-		case *GotoInput:
-			root.GoLine(root.Input.value)
-		case *HeaderInput:
-			root.SetHeader(root.Input.value)
-		case *DelimiterInput:
-			root.SetDelimiter(root.Input.value)
-		case *TABWidthInput:
-			root.SetTabWidth(root.Input.value)
-		case *tcell.EventKey:
-			root.message = ""
-			if root.Input.mode == normal {
-				root.DefaultKeyEvent(ev)
-			} else {
-				root.InputKeyEvent(ev)
-			}
-		case *tcell.EventResize:
-			root.Resize()
-		}
-	}
-}
-
 // GoLine will move to the specified line.
 func (root *Root) GoLine(input string) {
 	lineNum, err := strconv.Atoi(input)
-	root.Input.value = ""
 	if err != nil {
 		root.message = ErrInvalidNumber.Error()
 		return
 	}
+
 	root.moveNum(lineNum - root.Header - 1)
 	root.message = fmt.Sprintf("Moved to line %d", lineNum)
 }
@@ -430,7 +430,6 @@ func (root *Root) MarkLineNum(lineNum int) {
 // SetHeader sets the number of lines in the header.
 func (root *Root) SetHeader(input string) {
 	lineNum, err := strconv.Atoi(input)
-	root.Input.value = ""
 	if err != nil {
 		root.message = ErrInvalidNumber.Error()
 		return
@@ -442,6 +441,7 @@ func (root *Root) SetHeader(input string) {
 	if root.Header == lineNum {
 		return
 	}
+
 	root.Header = lineNum
 	root.message = fmt.Sprintf("Set Header %d", lineNum)
 	root.setWrapHeaderLen()
@@ -451,20 +451,20 @@ func (root *Root) SetHeader(input string) {
 // SetDelimiter sets the delimiter string.
 func (root *Root) SetDelimiter(input string) {
 	root.ColumnDelimiter = input
-	root.Input.value = ""
+	root.message = fmt.Sprintf("Set delimiter %s", input)
 }
 
 // SetTabWidth sets the tab width.
 func (root *Root) SetTabWidth(input string) {
 	width, err := strconv.Atoi(input)
-	root.Input.value = ""
 	if err != nil {
 		root.message = ErrInvalidNumber.Error()
 		return
 	}
 	if root.TabWidth == width {
 		return
 	}
+
 	root.TabWidth = width
 	root.message = fmt.Sprintf("Set tab width %d", width)
 	root.Model.ClearCache()