Modernize Go code

bypy/devenv.go

@@ -96,8 +96,8 @@ func get_dependencies(path string) (ans []dependency) {
 	for _, line := range lines("otool", "-L", path) {
 		line = strings.TrimSpace(line)
 		if strings.Contains(line, "compatibility") && !strings.HasSuffix(line, ":") {
-			idx := strings.IndexByte(line, '(')
-			dep := strings.TrimSpace(line[:idx])
+			before, _, _ := strings.Cut(line, "(")
+			dep := strings.TrimSpace(before)
 			ans = append(ans, dependency{path: dep, is_id: dep == install_name})
 		}
 	}

kittens/ask/choices.go

@@ -342,9 +342,9 @@ func GetChoices(o *Options) (response string, err error) {
 		lp.QueueWriteString(strings.Repeat("\r\n", y))
 		for _, line := range msg_lines {
 			if replacement_text != "" {
-				idx := strings.Index(line, replacement_text)
-				if idx > -1 {
-					x := wcswidth.Stringwidth(line[:idx])
+				before, _, ok := strings.Cut(line, replacement_text)
+				if ok {
+					x := wcswidth.Stringwidth(before)
 					replacement_range = Range{x, x + wcswidth.Stringwidth(replacement_text), y}
 				}
 			}

kittens/choose_files/results.go

@@ -292,13 +292,13 @@ func (h *Handler) draw_num_of_matches(num_shown, y int, in_progress bool) {
 	st := loop.SizedText{Subscale_denominator: 2, Subscale_numerator: 1, Vertical_alignment: 2, Width: 1}
 	graphemes := wcswidth.SplitIntoGraphemes(m)
 	for len(graphemes) > 0 {
-		s := ""
+		var s strings.Builder
 		for w := 0; w < 2 && len(graphemes) > 0; {
 			w += wcswidth.Stringwidth(graphemes[0])
-			s += graphemes[0]
+			s.WriteString(graphemes[0])
 			graphemes = graphemes[1:]
 		}
-		h.lp.DrawSizedText(s, st)
+		h.lp.DrawSizedText(s.String(), st)
 	}
 	if spinner != "" {
 		h.lp.QueueWriteString(spinner)

kittens/clipboard/read.go

@@ -388,11 +388,9 @@ func run_get_loop(opts *Options, args []string) (err error) {
 					if getting_data_for != current_mime {
 						if prev := requested_mimes[getting_data_for]; prev != nil && !prev.all_data_received {
 							prev.all_data_received = true
-							wg.Add(1)
-							go func() {
+							wg.Go(func() {
 								prev.commit()
-								wg.Done()
-							}()
+							})
 
 						}
 						getting_data_for = current_mime
@@ -405,11 +403,9 @@ func run_get_loop(opts *Options, args []string) (err error) {
 			case "DONE":
 				if prev := requested_mimes[getting_data_for]; getting_data_for != "" && prev != nil && !prev.all_data_received {
 					prev.all_data_received = true
-					wg.Add(1)
-					go func() {
+					wg.Go(func() {
 						prev.commit()
-						wg.Done()
-					}()
+					})
 					getting_data_for = ""
 				}
 				lp.Quit(0)

kittens/command_palette/main.go

@@ -255,7 +255,7 @@ func (h *Handler) updateFilter() {
 
 	// Score each column independently
 	colResults := [3][]fzf.Result{}
-	for c := 0; c < 3; c++ {
+	for c := range 3 {
 		results, err := h.matcher.Score(colSlices[c], h.query)
 		if err == nil {
 			colResults[c] = results
@@ -276,7 +276,7 @@ func (h *Handler) updateFilter() {
 		bestScore := uint(0)
 		bestCol := 0
 		var bestPositions []int
-		for c := 0; c < 3; c++ {
+		for c := range 3 {
 			if colResults[c] != nil && i < len(colResults[c]) && colResults[c][i].Score > bestScore {
 				bestScore = colResults[c][i].Score
 				bestCol = c
@@ -357,10 +357,7 @@ func (h *Handler) draw_screen() {
 	resultsStartY := 2
 	helpY := height - 1
 	hintsY := height
-	resultsHeight := helpY - resultsStartY
-	if resultsHeight < 1 {
-		resultsHeight = 1
-	}
+	resultsHeight := max(helpY-resultsStartY, 1)
 
 	h.results_start_y = resultsStartY
 	h.results_height = resultsHeight
@@ -381,10 +378,7 @@ func (h *Handler) draw_screen() {
 	h.lp.MoveCursorTo(1, helpY)
 	if b := h.selectedBinding(); b != nil && b.Help != "" {
 		helpStr := b.Help
-		maxLen := width - 2
-		if maxLen < 3 {
-			maxLen = 3
-		}
+		maxLen := max(width-2, 3)
 		if wcswidth.Stringwidth(helpStr) > maxLen {
 			// Truncate by runes to avoid breaking multi-byte characters
 			runes := []rune(helpStr)

kittens/command_palette/main_test.go

@@ -65,7 +65,7 @@ func TestFlattenAllBindings(t *testing.T) {
 func TestDefaultModeComesFirst(t *testing.T) {
 	h := newTestHandler()
 	// First 5 items should be from default mode
-	for i := 0; i < 5; i++ {
+	for i := range 5 {
 		if h.all_items[i].binding.Mode != "" {
 			t.Fatalf("Item %d should be from default mode, got mode=%q", i, h.all_items[i].binding.Mode)
 		}

kittens/diff/patch.go

@@ -215,7 +215,7 @@ func word_diff_center(left, right string, re *regexp.Regexp) Center {
 	// on exactly one side, the lines differ in word count and it makes more
 	// sense to highlight the single changed central region of the whole line.
 	max_idx := max(len(left_words), len(right_words))
-	for idx := 0; idx < max_idx; idx++ {
+	for idx := range max_idx {
 		lc := idx < len(left_words) && left_changed_abs[idx]
 		rc := idx < len(right_words) && right_changed_abs[idx]
 		if lc != rc {

kittens/show_key/legacy.go

@@ -9,6 +9,7 @@ import (
 	"github.com/kovidgoyal/kitty/tools/tty"
 	"io"
 	"os"
+	"strings"
 
 	"golang.org/x/sys/unix"
 )
@@ -17,24 +18,24 @@ var _ = fmt.Print
 
 func print_key(buf []byte, ctx *markup.Context) {
 	const ctrl_keys = "@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\\]^_"
-	unix := ""
-	send_text := ""
+	var unix strings.Builder
+	var send_text strings.Builder
 	for _, ch := range buf {
 		switch {
 		case int(ch) < len(ctrl_keys):
-			unix += "^" + ctrl_keys[ch:ch+1]
+			unix.WriteString("^" + ctrl_keys[ch:ch+1])
 		case ch == 127:
-			unix += "^?"
+			unix.WriteString("^?")
 		default:
-			unix += string(rune(ch))
+			unix.WriteString(string(rune(ch)))
 		}
 	}
 	for _, ch := range string(buf) {
 		q := fmt.Sprintf("%#v", string(ch))
-		send_text += q[1 : len(q)-1]
+		send_text.WriteString(q[1 : len(q)-1])
 	}
-	os.Stdout.WriteString(unix + "\t\t")
-	os.Stdout.WriteString(ctx.Yellow(send_text) + "\r\n")
+	os.Stdout.WriteString(unix.String() + "\t\t")
+	os.Stdout.WriteString(ctx.Yellow(send_text.String()) + "\r\n")
 }
 
 func run_legacy_loop(opts *Options) (err error) {

tools/cli/wcswidth_kitten.go

@@ -125,7 +125,7 @@ func run_tests(tests []*test_struct) (err error) {
 			case 'c':
 				lp.Quit(0)
 			case 'R':
-				if idx := bytes.IndexByte(data, ';'); idx > -1 {
+				if found := bytes.Contains(data, []byte{';'}); found {
 					if cpos, err := cpos_from_report(utils.UnsafeBytesToString(data[:len(data)-1])); err != nil {
 						return err
 					} else {

tools/cmd/mouse_demo/main.go

@@ -6,6 +6,7 @@ import (
 	"bytes"
 	"encoding/base64"
 	"fmt"
+	"slices"
 	"strconv"
 	"strings"
 
@@ -261,7 +262,7 @@ func Run(args []string) (rc int, err error) {
 		meta, payload, _ := strings.Cut(rest, ";")
 		// Parse metadata key=value pairs separated by ':'
 		meta_map := make(map[string]string)
-		for _, kv := range strings.Split(meta, ":") {
+		for kv := range strings.SplitSeq(meta, ":") {
 			k, v, _ := strings.Cut(kv, "=")
 			if k != "" {
 				meta_map[k] = v
@@ -300,19 +301,15 @@ func Run(args []string) (rc int, err error) {
 			mimes := strings.Fields(payload)
 			dnd.drop_mimes = mimes
 			// Request data for text/plain first, then text/uri-list
-			for _, m := range mimes {
-				if m == "text/plain" {
-					dnd.collecting = "text/plain"
-					lp.QueueWriteString(dnd_request_data("text/plain"))
-					return nil
-				}
+			if slices.Contains(mimes, "text/plain") {
+				dnd.collecting = "text/plain"
+				lp.QueueWriteString(dnd_request_data("text/plain"))
+				return nil
 			}
-			for _, m := range mimes {
-				if m == "text/uri-list" {
-					dnd.collecting = "text/uri-list"
-					lp.QueueWriteString(dnd_request_data("text/uri-list"))
-					return nil
-				}
+			if slices.Contains(mimes, "text/uri-list") {
+				dnd.collecting = "text/uri-list"
+				lp.QueueWriteString(dnd_request_data("text/uri-list"))
+				return nil
 			}
 			// Nothing to collect, signal done
 			lp.QueueWriteString(dnd_finish())
@@ -325,25 +322,23 @@ func Run(args []string) (rc int, err error) {
 				if dnd.collecting == "text/plain" {
 					text := dnd.collect_buf.String()
 					// Get first line
-					if idx := strings.IndexByte(text, '\n'); idx >= 0 {
-						dnd.plain_text = text[:idx]
+					if before, _, ok := strings.Cut(text, "\n"); ok {
+						dnd.plain_text = before
 					} else {
 						dnd.plain_text = text
 					}
 					dnd.collect_buf.Reset()
 					// Now request text/uri-list if available
-					for _, m := range dnd.drop_mimes {
-						if m == "text/uri-list" {
-							dnd.collecting = "text/uri-list"
-							lp.QueueWriteString(dnd_request_data("text/uri-list"))
-							return nil
-						}
+					if slices.Contains(dnd.drop_mimes, "text/uri-list") {
+						dnd.collecting = "text/uri-list"
+						lp.QueueWriteString(dnd_request_data("text/uri-list"))
+						return nil
 					}
 				} else if dnd.collecting == "text/uri-list" {
 					text := dnd.collect_buf.String()
 					dnd.collect_buf.Reset()
 					// Parse URI list: lines starting with # are comments
-					for _, line := range strings.Split(text, "\n") {
+					for line := range strings.SplitSeq(text, "\n") {
 						line = strings.TrimRight(line, "\r")
 						if line != "" && !strings.HasPrefix(line, "#") {
 							dnd.uri_list = append(dnd.uri_list, line)

tools/rsync/algorithm.go

@@ -646,10 +646,3 @@ func find_hash(hh []BlockHash, hv uint64) (uint64, bool) {
 	}
 	return 0, false
 }
-
-func min(a, b int) int {
-	if a < b {
-		return a
-	}
-	return b
-}

tools/tty/tty_bsd.go

@@ -1,6 +1,5 @@
 // License: GPLv3 Copyright: 2022, Kovid Goyal, <kovid at kovidgoyal.net>
 //go:build darwin || freebsd || openbsd || netbsd || dragonfly
-// +build darwin freebsd openbsd netbsd dragonfly
 
 package tty
 

tools/tui/readline/history.go

@@ -309,8 +309,8 @@ func (self *Readline) history_search_highlighter(text string, x, y int) string {
 	lines := utils.Splitlines(text)
 	for _, tok := range self.history_search.tokens {
 		for i, line := range lines {
-			if idx := strings.Index(line, tok); idx > -1 {
-				lines[i] = line[:idx] + self.fmt_ctx.Green(tok) + line[idx+len(tok):]
+			if before, after, ok := strings.Cut(line, tok); ok {
+				lines[i] = before + self.fmt_ctx.Green(tok) + after
 				break
 			}
 		}

tools/utils/strings.go

@@ -69,11 +69,11 @@ func ScanFuncForSeparator(sep string) StringScannerScanFunc {
 
 	}
 	return func(data string) (remaining_data, token string) {
-		idx := strings.Index(data, sep)
-		if idx < 0 {
+		before, after, ok := strings.Cut(data, sep)
+		if !ok {
 			return "", data
 		}
-		return data[idx+len(sep):], data[:idx]
+		return after, before
 	}
 }
 

tools/utils/style/colorspaces_bench_test.go

@@ -9,50 +9,50 @@ import (
 // Benchmark color parsing functions to demonstrate performance
 
 func BenchmarkParseOklch(b *testing.B) {
-	for i := 0; i < b.N; i++ {
+	for b.Loop() {
 		_, _ = parseOklch("0.5 0.1 180")
 	}
 }
 
 func BenchmarkParseLab(b *testing.B) {
-	for i := 0; i < b.N; i++ {
+	for b.Loop() {
 		_, _ = parseLab("50 0 0")
 	}
 }
 
 func BenchmarkParseColorHex(b *testing.B) {
-	for i := 0; i < b.N; i++ {
+	for b.Loop() {
 		_, _ = ParseColor("#ff0000")
 	}
 }
 
 func BenchmarkParseColorOklch(b *testing.B) {
-	for i := 0; i < b.N; i++ {
+	for b.Loop() {
 		_, _ = ParseColor("oklch(0.5 0.1 180)")
 	}
 }
 
 func BenchmarkParseColorLab(b *testing.B) {
-	for i := 0; i < b.N; i++ {
+	for b.Loop() {
 		_, _ = ParseColor("lab(50 0 0)")
 	}
 }
 
 func BenchmarkParseColorWithComment(b *testing.B) {
-	for i := 0; i < b.N; i++ {
+	for b.Loop() {
 		_, _ = ParseColor("oklch(0.5 0.1 180) # vibrant color")
 	}
 }
 
 // Benchmark the gamut mapping algorithm specifically
 func BenchmarkOklchToSrgbGamutMap(b *testing.B) {
-	for i := 0; i < b.N; i++ {
+	for b.Loop() {
 		oklchToSrgbGamutMap(0.7, 0.4, 25) // Very saturated color requiring gamut mapping
 	}
 }
 
 func BenchmarkOklchToSrgbGamutMapInGamut(b *testing.B) {
-	for i := 0; i < b.N; i++ {
+	for b.Loop() {
 		oklchToSrgbGamutMap(0.5, 0.05, 180) // Already in gamut
 	}
 }
@@ -71,8 +71,7 @@ func BenchmarkParseManyColors(b *testing.B) {
 		"green",
 	}
 
-	b.ResetTimer()
-	for i := 0; i < b.N; i++ {
+	for b.Loop() {
 		for _, color := range colors {
 			_, _ = ParseColor(color)
 		}

tools/wcswidth/char-props-data.go

@@ -388,10 +388,10 @@ var charprops_t3 = [106]CharProps{
 
 // Array accessor function that avoids bounds checking
 func charprops_for(x uint32) CharProps {
-	t1 := uintptr(*(*uint8)(unsafe.Pointer(uintptr(unsafe.Pointer(&charprops_t1[0])) + uintptr(x>>charprops_shift)*1)))
+	t1 := uintptr(*(*uint8)(unsafe.Add(unsafe.Pointer(&charprops_t1[0]), uintptr(x>>charprops_shift)*1)))
 	t1_shifted := (t1 << charprops_shift) + (uintptr(x) & charprops_mask)
-	t2 := uintptr(*(*uint8)(unsafe.Pointer(uintptr(unsafe.Pointer(&charprops_t2[0])) + t1_shifted*1)))
-	return *(*CharProps)(unsafe.Pointer(uintptr(unsafe.Pointer(&charprops_t3[0])) + t2*4))
+	t2 := uintptr(*(*uint8)(unsafe.Add(unsafe.Pointer(&charprops_t2[0]), t1_shifted*1)))
+	return *(*CharProps)(unsafe.Add(unsafe.Pointer(&charprops_t3[0]), t2*4))
 }
 
 const graphemesegmentationresult_mask = 15
@@ -3285,9 +3285,9 @@ var graphemesegmentationresult_t2 = [2880]GraphemeSegmentationResult{
 
 // Array accessor function that avoids bounds checking
 func graphemesegmentationresult_for(x uint16) GraphemeSegmentationResult {
-	t1 := uintptr(*(*uint8)(unsafe.Pointer(uintptr(unsafe.Pointer(&graphemesegmentationresult_t1[0])) + uintptr(x>>graphemesegmentationresult_shift)*1)))
+	t1 := uintptr(*(*uint8)(unsafe.Add(unsafe.Pointer(&graphemesegmentationresult_t1[0]), uintptr(x>>graphemesegmentationresult_shift)*1)))
 	t1_shifted := (t1 << graphemesegmentationresult_shift) + (uintptr(x) & graphemesegmentationresult_mask)
-	return *(*GraphemeSegmentationResult)(unsafe.Pointer(uintptr(unsafe.Pointer(&graphemesegmentationresult_t2[0])) + t1_shifted*2))
+	return *(*GraphemeSegmentationResult)(unsafe.Add(unsafe.Pointer(&graphemesegmentationresult_t2[0]), t1_shifted*2))
 }
 
 func grapheme_segmentation_key(r GraphemeSegmentationResult, ch CharProps) uint16 {