all: use simpler for loop iterations

Two of them can just use a boolean condition, and some others can use
the new integer range language feature.

While here, replace an unnecessary "string contains byte" func.

Signed-off-by: Daniel Martí <[email protected]>
Change-Id: I6a33e9d751e6d076b2e15c1e7cece061d92434ec
Reviewed-on: https://review.gerrithub.io/c/cue-lang/cue/+/1198838
TryBot-Result: CUEcueckoo <[email protected]>
Unity-Result: CUE porcuepine <[email protected]>
Reviewed-by: Matthew Sackman <[email protected]>

cmd/cue/cmd/def.go

@@ -64,7 +64,7 @@ func runDef(cmd *Command, args []string) error {
 
 	iter := b.instances()
 	defer iter.close()
-	for i := 0; iter.scan(); i++ {
+	for iter.scan() {
 		var err error
 		if f := iter.file(); f != nil {
 			err = e.EncodeFile(f)

cue/ast/astutil/apply.go

@@ -471,8 +471,7 @@ func (f *applier) After(c Cursor) bool {
 
 func (f *applier) visitComments(p Cursor, pos int8) {
 	c := &f.current
-	for i := 0; i < len(c.cg); i++ {
-		cg := c.cg[i]
+	for i, cg := range c.cg {
 		if cg.Position == pos {
 			continue
 		}

cue/literal/quote.go

@@ -143,7 +143,7 @@ func (f Form) Append(buf []byte, s string) []byte {
 		copy(nBuf, buf)
 		buf = nBuf
 	}
-	for i := 0; i < f.hashCount; i++ {
+	for range f.hashCount {
 		buf = append(buf, '#')
 	}
 	if f.multiline {
@@ -169,7 +169,7 @@ func (f Form) Append(buf []byte, s string) []byte {
 	} else {
 		buf = append(buf, f.quote)
 	}
-	for i := 0; i < f.hashCount; i++ {
+	for range f.hashCount {
 		buf = append(buf, '#')
 	}
 
@@ -280,7 +280,7 @@ func (f *Form) appendEscapedRune(buf []byte, r rune) []byte {
 
 func (f *Form) appendEscape(buf []byte) []byte {
 	buf = append(buf, '\\')
-	for i := 0; i < f.hashCount; i++ {
+	for range f.hashCount {
 		buf = append(buf, '#')
 	}
 	return buf

cue/literal/string.go

@@ -142,7 +142,7 @@ func ParseQuotes(start, end string) (q QuoteInfo, nStart, nEnd int, err error) {
 // are replaced with the corresponding non-surrogate code points.
 func (q QuoteInfo) Unquote(s string) (string, error) {
 	if len(s) > 0 && !q.multiline {
-		if contains(s, '\n') || contains(s, '\r') {
+		if strings.ContainsAny(s, "\n\r") {
 			return "", errSyntax
 		}
 
@@ -266,16 +266,6 @@ func isSimple(s string, quote rune) bool {
 	return true
 }
 
-// contains reports whether the string contains the byte c.
-func contains(s string, c byte) bool {
-	for i := 0; i < len(s); i++ {
-		if s[i] == c {
-			return true
-		}
-	}
-	return false
-}
-
 const (
 	terminatedByQuote = rune(-1)
 	terminatedByExpr  = rune(-2)

cue/scanner/scanner.go

@@ -383,7 +383,7 @@ exit:
 //
 // Must be compliant with https://tools.ietf.org/html/rfc4627.
 func (s *Scanner) scanEscape(quote quoteInfo) (ok, interpolation bool) {
-	for i := 0; i < quote.numHash; i++ {
+	for range quote.numHash {
 		if s.ch != '#' {
 			return true, false
 		}
@@ -519,7 +519,7 @@ func (s *Scanner) consumeStringClose(ch rune, quote quoteInfo) (next rune, atEnd
 }
 
 func (s *Scanner) scanHashes(maxHash int) int {
-	for i := 0; i < maxHash; i++ {
+	for i := range maxHash {
 		if s.ch != '#' {
 			return i
 		}

cue/types.go

@@ -146,7 +146,7 @@ func (o *hiddenStructValue) Lookup(key string) Value {
 func (o *structValue) marshalJSON() (b []byte, err errors.Error) {
 	b = append(b, '{')
 	n := o.Len()
-	for i := 0; i < n; i++ {
+	for i := range n {
 		k, v := o.At(i)
 		s, err := internaljson.Marshal(k)
 		if err != nil {
@@ -1771,7 +1771,7 @@ func (v Value) FillPath(p Path, x interface{}) Value {
 			list := &adt.ListLit{}
 			any := &adt.Top{}
 			// TODO(perf): make this a constant thing. This will be possible with the query extension.
-			for k := 0; k < i; k++ {
+			for range i {
 				list.Elems = append(list.Elems, any)
 			}
 			list.Elems = append(list.Elems, expr, &adt.Ellipsis{})
@@ -2299,7 +2299,7 @@ func (v Value) Walk(before func(Value) bool, after func(Value)) {
 			omitHidden:      true,
 			omitDefinitions: true,
 		})
-		for i := 0; i < obj.Len(); i++ {
+		for i := range obj.Len() {
 			_, v := obj.At(i)
 			// TODO: should we error on required fields, or visit them anyway?
 			// Walk is not designed to error at this moment, though.

encoding/toml/decode.go

@@ -313,7 +313,7 @@ func (d *Decoder) findArrayPrefix(key rootedKey) *openTableArray {
 // appending to the given parent key and returning the unquoted string elements.
 func decodeKey(key rootedKey, iter toml.Iterator) (rootedKey, []string) {
 	var elems []string
-	for i := 0; iter.Next(); i++ {
+	for iter.Next() {
 		name := string(iter.Node().Data)
 		// TODO(mvdan): use an append-like API once we have benchmarks
 		if len(key) > 0 {

internal/par/work.go

@@ -64,7 +64,7 @@ func (w *Work[T]) Do(n int, f func(item T)) {
 	w.f = f
 	w.wait.L = &w.mu
 
-	for i := 0; i < n-1; i++ {
+	for range n - 1 {
 		go w.runner()
 	}
 	w.runner()

mod/modzip/zip.go

@@ -841,7 +841,7 @@ func (e *zipError) Unwrap() error {
 func strToFold(s string) string {
 	// Fast path: all ASCII, no upper case.
 	// Most paths look like this already.
-	for i := 0; i < len(s); i++ {
+	for i := range len(s) {
 		c := s[i]
 		if c >= utf8.RuneSelf || 'A' <= c && c <= 'Z' {
 			goto Slow

pkg/list/list.go

@@ -140,7 +140,7 @@ func Repeat(x []cue.Value, count int) ([]cue.Value, error) {
 		return nil, fmt.Errorf("negative count")
 	}
 	var a []cue.Value
-	for i := 0; i < count; i++ {
+	for range count {
 		a = append(a, x...)
 	}
 	return a, nil

tools/flow/run.go

@@ -222,7 +222,7 @@ func (c *Controller) updateTaskResults(t *Task) bool {
 			list := &adt.ListLit{}
 			any := &adt.Top{}
 			// TODO(perf): make this a constant thing. This will be possible with the query extension.
-			for k := 0; k < i; k++ {
+			for range i {
 				list.Elems = append(list.Elems, any)
 			}
 			list.Elems = append(list.Elems, expr, &adt.Ellipsis{})