diff --git a/demo/classfile_nestetemplate/gop_autogen.go b/demo/classfile_nestetemplate/gop_autogen.go
index 9bea1c4..c2a1ec9 100644
--- a/demo/classfile_nestetemplate/gop_autogen.go
+++ b/demo/classfile_nestetemplate/gop_autogen.go
@@ -24,6 +24,9 @@ func (this *blog) MainEntry() {
 //line demo/classfile_nestetemplate/blog_yap.gox:10:1
 	this.Run(":8888")
 }
+func (this *blog) Main() {
+	yap.Gopt_App_Main(this)
+}
 func main() {
-	yap.Gopt_App_Main(new(blog))
+	new(blog).Main()
 }
diff --git a/internal/htmltempl/template.go b/internal/htmltempl/template.go
new file mode 100644
index 0000000..93e463c
--- /dev/null
+++ b/internal/htmltempl/template.go
@@ -0,0 +1,75 @@
+/*
+ * Copyright (c) 2023 The GoPlus Authors (goplus.org). All rights reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package htmltempl
+
+import (
+	"bytes"
+	"fmt"
+	"html/template"
+	"io/fs"
+	"log"
+	"path"
+	"strings"
+	_ "unsafe"
+
+	"github.com/goplus/yap/internal/templ"
+)
+
+// Template is the representation of a parsed template. The *parse.Tree
+// field is exported only for use by html/template and should be treated
+// as unexported by all other clients.
+type Template struct {
+	*template.Template
+}
+
+func (p *Template) InitTemplates(fsys fs.FS, delimLeft, delimRight, suffix string) {
+	tpl, err := parseFS(fsys, delimLeft, delimRight, suffix)
+	if err != nil {
+		log.Panicln(err)
+	}
+	p.Template = tpl
+}
+
+//go:linkname parseFiles html/template.parseFiles
+func parseFiles(t *template.Template, readFile func(string) (string, []byte, error), filenames ...string) (*template.Template, error)
+
+func parseFS(fsys fs.FS, delimLeft, delimRight, suffix string) (*template.Template, error) {
+	pattern := "*" + suffix
+	filenames, err := fs.Glob(fsys, pattern)
+	if err != nil {
+		return nil, err
+	}
+	if len(filenames) == 0 {
+		return nil, fmt.Errorf("template: pattern matches no files: %#q", pattern)
+	}
+	t := template.New("").Delims(delimLeft, delimRight)
+	return parseFiles(t, readFileFS(fsys, delimLeft, delimRight, suffix), filenames...)
+}
+
+func readFileFS(fsys fs.FS, delimLeft, delimRight, suffix string) func(string) (string, []byte, error) {
+	return func(file string) (name string, b []byte, err error) {
+		name = strings.TrimSuffix(path.Base(file), suffix)
+		if b, err = fs.ReadFile(fsys, file); err != nil {
+			return
+		}
+		var buf bytes.Buffer
+		if templ.TranslateEx(&buf, string(b), delimLeft, delimRight) {
+			b = buf.Bytes()
+		}
+		return
+	}
+}
diff --git a/internal/templ/template.go b/internal/templ/template.go
index c497fd6..a8837fb 100644
--- a/internal/templ/template.go
+++ b/internal/templ/template.go
@@ -21,15 +21,35 @@ import (
 )
 
 func Translate(text string) string {
+	var b strings.Builder
+	if TranslateEx(&b, text, "{{", "}}") {
+		return b.String()
+	}
+	return text
+}
+
+type iBuilder interface {
+	Grow(n int)
+	WriteString(s string) (int, error)
+	String() string
+}
+
+func TranslateEx[Builder iBuilder](b Builder, text, delimLeft, delimRight string) bool {
 	offs := make([]int, 0, 16)
 	base := 0
+	if delimLeft == "" {
+		delimLeft = "{{"
+	}
+	if delimRight == "" {
+		delimRight = "}}"
+	}
 	for {
-		pos := strings.Index(text[base:], "{{")
+		pos := strings.Index(text[base:], delimLeft)
 		if pos < 0 {
 			break
 		}
 		begin := base + pos + 2 // script begin
-		n := strings.Index(text[begin:], "}}")
+		n := strings.Index(text[begin:], delimRight)
 		if n < 0 {
 			n = len(text) - begin // script length
 		}
@@ -51,19 +71,19 @@ func Translate(text string) string {
 	}
 	n := len(offs)
 	if n == 0 {
-		return text
+		return false
 	}
-	var b strings.Builder
 	b.Grow(len(text) + n*4)
 	base = 0
+	delimRightLeft := delimRight + delimLeft
 	for i := 0; i < n; i++ {
 		off := offs[i]
 		b.WriteString(text[base:off])
-		b.WriteString("}}{{")
+		b.WriteString(delimRightLeft)
 		base = off
 	}
 	b.WriteString(text[base:])
-	return b.String()
+	return true
 }
 
 func isSpace(c byte) bool {
diff --git a/internal/templ/template_test.go b/internal/templ/template_test.go
index 53e97ec..1d9f26e 100644
--- a/internal/templ/template_test.go
+++ b/internal/templ/template_test.go
@@ -16,7 +16,10 @@
 
 package templ
 
-import "testing"
+import (
+	"bytes"
+	"testing"
+)
 
 const yapScriptIn = `
 <html>
@@ -95,4 +98,9 @@ efg
 	if ret := Translate(noScriptEnd); ret != noScriptEndOut {
 		t.Fatal("translate(noScriptEnd):", ret)
 	}
+	var b bytes.Buffer
+	TranslateEx(&b, yapScriptIn, "", "")
+	if b.String() != yapScriptOut {
+		t.Fatal("TranslateEx:", b.String())
+	}
 }
diff --git a/template.go b/template.go
deleted file mode 100644
index 883358f..0000000
--- a/template.go
+++ /dev/null
@@ -1,164 +0,0 @@
-/*
- * Copyright (c) 2023 The GoPlus Authors (goplus.org). All rights reserved.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package yap
-
-import (
-	"fmt"
-	"html/template"
-	"io/fs"
-	"log"
-	"os"
-	"path/filepath"
-	"strings"
-
-	"github.com/goplus/yap/internal/templ"
-)
-
-// Template is the representation of a parsed template. The *parse.Tree
-// field is exported only for use by html/template and should be treated
-// as unexported by all other clients.
-type Template struct {
-	*template.Template
-}
-
-// NewTemplate allocates a new, undefined template with the given name.
-func NewTemplate(name string) *Template {
-	return &Template{template.New(name)}
-}
-func (t *Template) NewTemplate(name string) *Template {
-	return &Template{Template: t.Template.New(name)}
-}
-
-func (t Template) Parse(text string) (ret Template, err error) {
-	ret.Template, err = t.Template.Parse(templ.Translate(text))
-	return
-}
-
-func ParseFSFile(f fs.FS, file string) (t Template, err error) {
-	b, err := fs.ReadFile(f, file)
-	if err != nil {
-		return
-	}
-	name := filepath.Base(file)
-	return NewTemplate(name).Parse(string(b))
-}
-
-func ParseFiles(filenames ...string) (*Template, error) {
-	return parseFiles(nil, readFileOS, filenames...)
-}
-
-func (t *Template) ParseFiles(filenames ...string) (*Template, error) {
-	return parseFiles(t, readFileOS, filenames...)
-}
-
-func parseFiles(t *Template, readFile func(string) (string, []byte, error), filenames ...string) (*Template, error) {
-
-	if len(filenames) == 0 {
-		return nil, fmt.Errorf("yap/template: no files named in call to ParseFiles")
-	}
-	for _, filename := range filenames {
-		name, b, err := readFile(filename)
-		if err != nil {
-			return nil, err
-		}
-		s := string(b)
-		var tmpl *Template
-		if t == nil {
-			t = NewTemplate(name)
-		}
-		if name == t.Name() {
-			tmpl = t
-		} else {
-			tmpl = t.NewTemplate(name)
-		}
-		_, err = tmpl.Parse(s)
-		if err != nil {
-			return nil, err
-		}
-	}
-	log.Println("yap/template list:")
-	for i, t2 := range t.Templates() {
-		log.Println(i, t2.Name())
-	}
-	return t, nil
-}
-
-func ParseGlob(pattern string) (*Template, error) {
-	return parseGlob(nil, pattern)
-}
-
-func (t *Template) ParseGlob(pattern string) (*Template, error) {
-	return parseGlob(t, pattern)
-}
-
-func parseGlob(t *Template, pattern string) (*Template, error) {
-	filenames, err := filepath.Glob(pattern)
-	if err != nil {
-		return nil, err
-	}
-	if len(filenames) == 0 {
-		return nil, fmt.Errorf("html/template: pattern matches no files: %#q", pattern)
-	}
-	return parseFiles(t, readFileOS, filenames...)
-}
-
-// ParseFS is like ParseFiles or ParseGlob but reads from the file system fs
-// instead of the host operating system's file system.
-// It accepts a list of glob patterns.
-// (Note that most file names serve as glob patterns matching only themselves.)
-func ParseFS(fs fs.FS, patterns ...string) (*Template, error) {
-	return parseFS(nil, fs, patterns)
-}
-
-// ParseFS is like ParseFiles or ParseGlob but reads from the file system fs
-// instead of the host operating system's file system.
-// It accepts a list of glob patterns.
-// (Note that most file names serve as glob patterns matching only themselves.)
-func (t *Template) ParseFS(fs fs.FS, patterns ...string) (*Template, error) {
-	return parseFS(t, fs, patterns)
-}
-
-func parseFS(t *Template, fsys fs.FS, patterns []string) (*Template, error) {
-	var filenames []string
-	for _, pattern := range patterns {
-		list, err := fs.Glob(fsys, pattern)
-		if err != nil {
-			return nil, err
-		}
-		if len(list) == 0 {
-			return nil, fmt.Errorf("template: pattern matches no files: %#q", pattern)
-		}
-		filenames = append(filenames, list...)
-	}
-	return parseFiles(t, readFileFS(fsys), filenames...)
-}
-
-func readFileOS(file string) (name string, b []byte, err error) {
-	name = filepath.Base(file)
-	b, err = os.ReadFile(file)
-	return
-}
-
-func readFileFS(fsys fs.FS) func(string) (string, []byte, error) {
-	return func(file string) (name string, b []byte, err error) {
-		name = filepath.ToSlash(file)
-		// compatible yap template name for older versions of yap, without the suffix "_ yap.html"
-		name = strings.TrimSuffix(name, "_yap.html")
-		b, err = fs.ReadFile(fsys, file)
-		return
-	}
-}
diff --git a/yap.go b/yap.go
index 64eb3e8..adc010a 100644
--- a/yap.go
+++ b/yap.go
@@ -24,6 +24,7 @@ import (
 	"os"
 	"strings"
 
+	"github.com/goplus/yap/internal/htmltempl"
 	"github.com/goplus/yap/noredirect"
 )
 
@@ -33,7 +34,9 @@ type Engine struct {
 	router
 	Mux *http.ServeMux
 
-	tpl *Template
+	delimLeft, delimRight string
+
+	tpl htmltempl.Template
 	fs  fs.FS
 	las func(addr string, handler http.Handler) error
 }
@@ -68,15 +71,6 @@ func (p *Engine) initYapFS(fsys fs.FS) {
 	p.fs = fsys
 }
 
-// Load template
-func (p *Engine) loadTemplate() {
-	t, err := parseFS(NewTemplate(""), p.yapFS(), []string{"*_yap.html"})
-	if err != nil {
-		log.Panicln(err)
-	}
-	p.tpl = t
-}
-
 func (p *Engine) yapFS() fs.FS {
 	if p.fs == nil {
 		p.initYapFS(os.DirFS("."))
@@ -163,9 +157,15 @@ func (p *Engine) SetLAS(listenAndServe func(addr string, handler http.Handler) e
 	p.las = listenAndServe
 }
 
+// SetDelims sets the action delimiters to the specified strings. Nested template definitions
+// will inherit the settings. An empty delimiter stands for the corresponding default: {{ or }}.
+func (p *Engine) SetDelims(left, right string) {
+	p.delimLeft, p.delimRight = left, right
+}
+
 func (p *Engine) templ(path string) *template.Template {
-	if p.tpl == nil {
-		p.loadTemplate()
+	if p.tpl.Template == nil {
+		p.tpl.InitTemplates(p.yapFS(), p.delimLeft, p.delimRight, "_yap.html")
 	}
 	return p.tpl.Lookup(path)
 }
diff --git a/ytest/demo/match/hello/gop_autogen.go b/ytest/demo/match/hello/gop_autogen.go
index 6e47be0..bf095be 100644
--- a/ytest/demo/match/hello/gop_autogen.go
+++ b/ytest/demo/match/hello/gop_autogen.go
@@ -43,11 +43,11 @@ func (this *hello) Main() {
 	id := "123"
 //line ytest/demo/match/hello/hello_yapt.gox:4:1
 	this.Get(stringutil.Concat("http://foo.com/p/", id))
-//line ytest/demo/match/hello/hello_yapt.gox:5:1
-	this.RetWith(200)
 //line ytest/demo/match/hello/hello_yapt.gox:6:1
+	this.RetWith(200)
+//line ytest/demo/match/hello/hello_yapt.gox:7:1
 	this.Json(map[string]string{"id": id})
-//line ytest/demo/match/hello/hello_yapt.gox:9:1
+//line ytest/demo/match/hello/hello_yapt.gox:11:1
 	fmt.Println("OK")
 }
 func (this *hello) Classfname() string {