new

Change-Id: Ibd5e3b279b74a7b20bf207eed5cceaf200791714

Author: qiulaidongfeng

src/text/template/exec.go

@@ -439,17 +439,27 @@ func (s *state) walkRange(dot reflect.Value, r *parse.RangeNode) {
 		if val.Type().CanSeq() {
 			if len(r.Pipe.Decl) > 1 {
 				s.errorf("can't use %s iterate over more than one variable", val)
-				return
+				break
 			}
+			run := false
 			for v := range val.Seq() {
+				run = true
 				oneIteration(v, reflect.Value{}, true)
 			}
+			if !run {
+				break
+			}
 			return
 		}
 		if val.Type().CanSeq2() {
+			run := false
 			for i, v := range val.Seq2() {
+				run = true
 				oneIteration(i, v, true)
 			}
+			if !run {
+				break
+			}
 			return
 		}
 		fallthrough

src/text/template/exec_test.go

@@ -10,6 +10,7 @@ import (
 	"flag"
 	"fmt"
 	"io"
+	"iter"
 	"reflect"
 	"strings"
 	"sync"
@@ -601,15 +602,17 @@ var execTests = []execTest{
 	{"declare in range", "{{range $x := .PSI}}<{{$foo:=$x}}{{$x}}>{{end}}", "<21><22><23>", tVal, true},
 	{"range count", `{{range $i, $x := count 5}}[{{$i}}]{{$x}}{{end}}`, "[0]a[1]b[2]c[3]d[4]e", tVal, true},
 	{"range nil count", `{{range $i, $x := count 0}}{{else}}empty{{end}}`, "empty", tVal, true},
-	{"range iter.Seq[int]", `{{range $i := .}}{{$i}}{{end}}`, "01", fVal1, true},
-	{"i = range iter.Seq[int]", `{{$i := 0}}{{range $i = .}}{{$i}}{{end}}`, "01", fVal1, true},
-	{"range iter.Seq[int] over two var", `{{range $i, $c := .}}{{$c}}{{end}}`, "", fVal1, false},
-	{"i, c := range iter.Seq2[int,int]", `{{range $i, $c := .}}{{$i}}{{$c}}{{end}}`, "0112", fVal2, true},
-	{"i, c = range iter.Seq2[int,int]", `{{$i := 0}}{{$c := 0}}{{range $i, $c = .}}{{$i}}{{$c}}{{end}}`, "0112", fVal2, true},
-	{"i = range iter.Seq2[int,int]", `{{$i := 0}}{{range $i = .}}{{$i}}{{end}}`, "01", fVal2, true},
-	{"i := range iter.Seq2[int,int]", `{{range $i := .}}{{$i}}{{end}}`, "01", fVal2, true},
-	{"i,c,x range iter.Seq2[int,int]", `{{$i := 0}}{{$c := 0}}{{$x := 0}}{{range $i, $c = .}}{{$i}}{{$c}}{{end}}`, "0112", fVal2, true},
-	{"i,x range iter.Seq[int]", `{{$i := 0}}{{$x := 0}}{{range $i = .}}{{$i}}{{end}}`, "01", fVal1, true},
+	{"range iter.Seq[int]", `{{range $i := .}}{{$i}}{{end}}`, "01", fVal1(2), true},
+	{"i = range iter.Seq[int]", `{{$i := 0}}{{range $i = .}}{{$i}}{{end}}`, "01", fVal1(2), true},
+	{"range iter.Seq[int] over two var", `{{range $i, $c := .}}{{$c}}{{end}}`, "", fVal1(2), false},
+	{"i, c := range iter.Seq2[int,int]", `{{range $i, $c := .}}{{$i}}{{$c}}{{end}}`, "0112", fVal2(2), true},
+	{"i, c = range iter.Seq2[int,int]", `{{$i := 0}}{{$c := 0}}{{range $i, $c = .}}{{$i}}{{$c}}{{end}}`, "0112", fVal2(2), true},
+	{"i = range iter.Seq2[int,int]", `{{$i := 0}}{{range $i = .}}{{$i}}{{end}}`, "01", fVal2(2), true},
+	{"i := range iter.Seq2[int,int]", `{{range $i := .}}{{$i}}{{end}}`, "01", fVal2(2), true},
+	{"i,c,x range iter.Seq2[int,int]", `{{$i := 0}}{{$c := 0}}{{$x := 0}}{{range $i, $c = .}}{{$i}}{{$c}}{{end}}`, "0112", fVal2(2), true},
+	{"i,x range iter.Seq[int]", `{{$i := 0}}{{$x := 0}}{{range $i = .}}{{$i}}{{end}}`, "01", fVal1(2), true},
+	{"range iter.Seq[int] else", `{{range $i := .}}{{$i}}{{else}}empty{{end}}`, "empty", fVal1(0), true},
+	{"range iter.Seq2[int,int] else", `{{range $i := .}}{{$i}}{{else}}empty{{end}}`, "empty", fVal2(0), true},
 
 	// Cute examples.
 	{"or as if true", `{{or .SI "slice is empty"}}`, "[3 4 5]", tVal, true},
@@ -714,18 +717,22 @@ var execTests = []execTest{
 	{"issue60801", "{{$k := 0}}{{$v := 0}}{{range $k, $v = .AI}}{{$k}}={{$v}} {{end}}", "0=3 1=4 2=5 ", tVal, true},
 }
 
-func fVal1(yield func(int) bool) {
-	for i := range 2 {
-		if !yield(i) {
-			break
+func fVal1(i int) iter.Seq[int] {
+	return func(yield func(int) bool) {
+		for v := range i {
+			if !yield(v) {
+				break
+			}
 		}
 	}
 }
 
-func fVal2(yield func(int, int) bool) {
-	for i := range 2 {
-		if !yield(i, i+1) {
-			break
+func fVal2(i int) iter.Seq2[int, int] {
+	return func(yield func(int, int) bool) {
+		for v := range i {
+			if !yield(v, v+1) {
+				break
+			}
 		}
 	}
 }