Introduce more strict numeric types for different kinds of indices

buffer.go

@@ -4,13 +4,14 @@ import (
 	"strings"
 
 	"github.com/elk-language/go-prompt/internal/debug"
+	istrings "github.com/elk-language/go-prompt/internal/strings"
 )
 
 // Buffer emulates the console buffer.
 type Buffer struct {
 	workingLines   []string // The working lines. Similar to history
-	workingIndex   int
-	cursorPosition int
+	workingIndex   int      // index of the current line
+	cursorPosition istrings.RuneIndex
 	cacheDocument  *Document
 	lastKeyStroke  Key
 }
@@ -36,44 +37,43 @@ func (b *Buffer) Document() (d *Document) {
 
 // DisplayCursorPosition returns the cursor position on rendered text on terminal emulators.
 // So if Document is "日本(cursor)語", DisplayedCursorPosition returns 4 because '日' and '本' are double width characters.
-func (b *Buffer) DisplayCursorPosition(columns int) Position {
+func (b *Buffer) DisplayCursorPosition(columns istrings.StringWidth) Position {
 	return b.Document().DisplayCursorPosition(columns)
 }
 
 // InsertText insert string from current line.
-func (b *Buffer) InsertText(v string, overwrite bool, moveCursor bool) {
-	or := []rune(b.Text())
-	oc := b.cursorPosition
+func (b *Buffer) InsertText(text string, overwrite bool, moveCursor bool) {
+	currentTextRunes := []rune(b.Text())
+	cursor := b.cursorPosition
 
 	if overwrite {
-		overwritten := string(or[oc:])
-		if len(overwritten) >= oc+len(v) {
-			overwritten = string(or[oc : oc+len(v)])
+		overwritten := string(currentTextRunes[cursor:])
+		if len(overwritten) >= int(cursor)+len(text) {
+			overwritten = string(currentTextRunes[cursor : cursor+istrings.RuneLen(text)])
 		}
-		if strings.Contains(overwritten, "\n") {
-			i := strings.IndexAny(overwritten, "\n")
+		if i := strings.IndexAny(overwritten, "\n"); i != -1 {
 			overwritten = overwritten[:i]
 		}
-		b.setText(string(or[:oc]) + v + string(or[oc+len(overwritten):]))
+		b.setText(string(currentTextRunes[:cursor]) + text + string(currentTextRunes[cursor+istrings.RuneLen(overwritten):]))
 	} else {
-		b.setText(string(or[:oc]) + v + string(or[oc:]))
+		b.setText(string(currentTextRunes[:cursor]) + text + string(currentTextRunes[cursor:]))
 	}
 
 	if moveCursor {
-		b.cursorPosition += len([]rune(v))
+		b.cursorPosition += istrings.RuneLen(text)
 	}
 }
 
 // SetText method to set text and update cursorPosition.
 // (When doing this, make sure that the cursor_position is valid for this text.
 // text/cursor_position should be consistent at any time, otherwise set a Document instead.)
-func (b *Buffer) setText(v string) {
-	debug.Assert(b.cursorPosition <= len([]rune(v)), "length of input should be shorter than cursor position")
-	b.workingLines[b.workingIndex] = v
+func (b *Buffer) setText(text string) {
+	debug.Assert(b.cursorPosition <= istrings.RuneLen(text), "length of input should be shorter than cursor position")
+	b.workingLines[b.workingIndex] = text
 }
 
 // Set cursor position. Return whether it changed.
-func (b *Buffer) setCursorPosition(p int) {
+func (b *Buffer) setCursorPosition(p istrings.RuneIndex) {
 	if p > 0 {
 		b.cursorPosition = p
 	} else {
@@ -88,13 +88,13 @@ func (b *Buffer) setDocument(d *Document) {
 }
 
 // CursorLeft move to left on the current line.
-func (b *Buffer) CursorLeft(count int) {
+func (b *Buffer) CursorLeft(count istrings.RuneCount) {
 	l := b.Document().GetCursorLeftPosition(count)
 	b.cursorPosition += l
 }
 
 // CursorRight move to right on the current line.
-func (b *Buffer) CursorRight(count int) {
+func (b *Buffer) CursorRight(count istrings.RuneCount) {
 	l := b.Document().GetCursorRightPosition(count)
 	b.cursorPosition += l
 }
@@ -114,7 +114,7 @@ func (b *Buffer) CursorDown(count int) {
 }
 
 // DeleteBeforeCursor delete specified number of characters before cursor and return the deleted text.
-func (b *Buffer) DeleteBeforeCursor(count int) (deleted string) {
+func (b *Buffer) DeleteBeforeCursor(count istrings.RuneCount) (deleted string) {
 	debug.Assert(count >= 0, "count should be positive")
 	r := []rune(b.Text())
 
@@ -126,7 +126,7 @@ func (b *Buffer) DeleteBeforeCursor(count int) (deleted string) {
 		deleted = string(r[start:b.cursorPosition])
 		b.setDocument(&Document{
 			Text:           string(r[:start]) + string(r[b.cursorPosition:]),
-			cursorPosition: b.cursorPosition - len([]rune(deleted)),
+			cursorPosition: b.cursorPosition - istrings.RuneIndex(len([]rune(deleted))),
 		})
 	}
 	return
@@ -142,13 +142,19 @@ func (b *Buffer) NewLine(copyMargin bool) {
 }
 
 // Delete specified number of characters and Return the deleted text.
-func (b *Buffer) Delete(count int) (deleted string) {
+func (b *Buffer) Delete(count istrings.RuneCount) string {
 	r := []rune(b.Text())
-	if b.cursorPosition < len(r) {
-		deleted = b.Document().TextAfterCursor()[:count]
-		b.setText(string(r[:b.cursorPosition]) + string(r[b.cursorPosition+len(deleted):]))
+	if b.cursorPosition < istrings.RuneIndex(len(r)) {
+		textAfterCursor := b.Document().TextAfterCursor()
+		textAfterCursorRunes := []rune(textAfterCursor)
+		deletedRunes := textAfterCursorRunes[:count]
+		b.setText(string(r[:b.cursorPosition]) + string(r[b.cursorPosition+istrings.RuneCount(len(deletedRunes)):]))
+
+		deleted := string(deletedRunes)
+		return deleted
 	}
-	return
+
+	return ""
 }
 
 // JoinNextLine joins the next line to the current one by deleting the line ending after the current line.

buffer_test.go

@@ -3,6 +3,8 @@ package prompt
 import (
 	"reflect"
 	"testing"
+
+	istrings "github.com/elk-language/go-prompt/internal/strings"
 )
 
 func TestNewBuffer(t *testing.T) {
@@ -23,8 +25,8 @@ func TestBuffer_InsertText(t *testing.T) {
 		t.Errorf("Text should be %#v, got %#v", "some_text", b.Text())
 	}
 
-	if b.cursorPosition != len("some_text") {
-		t.Errorf("cursorPosition should be %#v, got %#v", len("some_text"), b.cursorPosition)
+	if b.cursorPosition != istrings.RuneLen("some_text") {
+		t.Errorf("cursorPosition should be %#v, got %#v", istrings.RuneLen("some_text"), b.cursorPosition)
 	}
 }
 
@@ -36,8 +38,8 @@ func TestBuffer_InsertText_Overwrite(t *testing.T) {
 		t.Errorf("Text should be %#v, got %#v", "ABC", b.Text())
 	}
 
-	if b.cursorPosition != len("ABC") {
-		t.Errorf("cursorPosition should be %#v, got %#v", len("ABC"), b.cursorPosition)
+	if b.cursorPosition != istrings.RuneLen("ABC") {
+		t.Errorf("cursorPosition should be %#v, got %#v", istrings.RuneLen("ABC"), b.cursorPosition)
 	}
 
 	b.CursorLeft(1)
@@ -85,8 +87,8 @@ func TestBuffer_CursorMovement(t *testing.T) {
 	if b.Text() != "some_teAxt" {
 		t.Errorf("Text should be %#v, got %#v", "some_teAxt", b.Text())
 	}
-	if b.cursorPosition != len("some_teA") {
-		t.Errorf("Text should be %#v, got %#v", len("some_teA"), b.cursorPosition)
+	if b.cursorPosition != istrings.RuneLen("some_teA") {
+		t.Errorf("Text should be %#v, got %#v", istrings.RuneLen("some_teA"), b.cursorPosition)
 	}
 
 	// Moving over left character counts.
@@ -95,8 +97,8 @@ func TestBuffer_CursorMovement(t *testing.T) {
 	if b.Text() != "Asome_teAxt" {
 		t.Errorf("Text should be %#v, got %#v", "some_teAxt", b.Text())
 	}
-	if b.cursorPosition != len("A") {
-		t.Errorf("Text should be %#v, got %#v", len("some_teA"), b.cursorPosition)
+	if b.cursorPosition != istrings.RuneLen("A") {
+		t.Errorf("Text should be %#v, got %#v", istrings.RuneLen("some_teA"), b.cursorPosition)
 	}
 
 	// TODO: Going right already at right end.
@@ -109,6 +111,10 @@ func TestBuffer_CursorMovement_WithMultiByte(t *testing.T) {
 	if l := b.Document().TextAfterCursor(); l != "お" {
 		t.Errorf("Should be 'お', but got %s", l)
 	}
+	b.InsertText("żółć", true, true)
+	if b.Text() != "あいうえżółć" {
+		t.Errorf("Text should be %#v, got %#v", "あいうえżółć", b.Text())
+	}
 }
 
 func TestBuffer_CursorUp(t *testing.T) {
@@ -141,17 +147,17 @@ func TestBuffer_CursorDown(t *testing.T) {
 
 	// Normally going down
 	b.CursorDown(1)
-	if b.Document().cursorPosition != len("line1\nlin") {
-		t.Errorf("Should be %#v, got %#v", len("line1\nlin"), b.Document().cursorPosition)
+	if b.Document().cursorPosition != istrings.RuneLen("line1\nlin") {
+		t.Errorf("Should be %#v, got %#v", istrings.RuneLen("line1\nlin"), b.Document().cursorPosition)
 	}
 
 	// Going down to a line that's storter.
 	b = NewBuffer()
 	b.InsertText("long line1\na\nb", false, true)
 	b.cursorPosition = 3
 	b.CursorDown(1)
-	if b.Document().cursorPosition != len("long line1\na") {
-		t.Errorf("Should be %#v, got %#v", len("long line1\na"), b.Document().cursorPosition)
+	if b.Document().cursorPosition != istrings.RuneLen("long line1\na") {
+		t.Errorf("Should be %#v, got %#v", istrings.RuneLen("long line1\na"), b.Document().cursorPosition)
 	}
 }
 
@@ -167,8 +173,8 @@ func TestBuffer_DeleteBeforeCursor(t *testing.T) {
 	if deleted != "e" {
 		t.Errorf("Should be %#v, got %#v", deleted, "e")
 	}
-	if b.cursorPosition != len("some_t") {
-		t.Errorf("Should be %#v, got %#v", len("some_t"), b.cursorPosition)
+	if b.cursorPosition != istrings.RuneLen("some_t") {
+		t.Errorf("Should be %#v, got %#v", istrings.RuneLen("some_t"), b.cursorPosition)
 	}
 
 	// Delete over the characters length before cursor.

completion.go

@@ -4,6 +4,7 @@ import (
 	"strings"
 
 	"github.com/elk-language/go-prompt/internal/debug"
+	istrings "github.com/elk-language/go-prompt/internal/strings"
 	runewidth "github.com/mattn/go-runewidth"
 )
 
@@ -155,7 +156,7 @@ func formatTexts(o []string, max int, prefix, suffix string) (new []string, widt
 	return n, lenPrefix + width + lenSuffix
 }
 
-func formatSuggestions(suggests []Suggest, max int) (new []Suggest, width int) {
+func formatSuggestions(suggests []Suggest, max int) (new []Suggest, width istrings.StringWidth) {
 	num := len(suggests)
 	new = make([]Suggest, num)
 
@@ -177,7 +178,7 @@ func formatSuggestions(suggests []Suggest, max int) (new []Suggest, width int) {
 	for i := 0; i < num; i++ {
 		new[i] = Suggest{Text: left[i], Description: right[i]}
 	}
-	return new, leftWidth + rightWidth
+	return new, istrings.StringWidth(leftWidth + rightWidth)
 }
 
 // Constructor option for CompletionManager.

completion_test.go

@@ -3,14 +3,16 @@ package prompt
 import (
 	"reflect"
 	"testing"
+
+	istrings "github.com/elk-language/go-prompt/internal/strings"
 )
 
 func TestFormatShortSuggestion(t *testing.T) {
 	var scenarioTable = []struct {
 		in       []Suggest
 		expected []Suggest
 		max      int
-		exWidth  int
+		exWidth  istrings.StringWidth
 	}{
 		{
 			in: []Suggest{
@@ -38,7 +40,7 @@ func TestFormatShortSuggestion(t *testing.T) {
 				{Text: " coconut ", Description: " This is coconut. "},
 			},
 			max:     100,
-			exWidth: len(" apple   " + " This is apple.   "),
+			exWidth: istrings.StringWidth(len(" apple   " + " This is apple.   ")),
 		},
 		{
 			in: []Suggest{
@@ -82,7 +84,7 @@ func TestFormatShortSuggestion(t *testing.T) {
 				{Text: " --include-extended-apis       ", Description: " --------------... "},
 			},
 			max:     50,
-			exWidth: len(" --include-extended-apis       " + " ---------------..."),
+			exWidth: istrings.StringWidth(len(" --include-extended-apis       " + " ---------------...")),
 		},
 		{
 			in: []Suggest{
@@ -102,7 +104,7 @@ func TestFormatShortSuggestion(t *testing.T) {
 				{Text: " --include-extended-apis       ", Description: " If true, include definitions of new APIs via calls to the API server. [default true]                                                            "},
 			},
 			max:     500,
-			exWidth: len(" --include-extended-apis       " + " If true, include definitions of new APIs via calls to the API server. [default true]                                                            "),
+			exWidth: istrings.StringWidth(len(" --include-extended-apis       " + " If true, include definitions of new APIs via calls to the API server. [default true]                                                            ")),
 		},
 	}