diff --git a/README.md b/README.md
index e0c59ee..9adaee0 100644
--- a/README.md
+++ b/README.md
@@ -64,6 +64,25 @@ Available template params:
   {{.Params}}         can access given parameters by '-p' option, which must be defined on 'Params' field of markdown header.
 ```
 
+Available template functions:
+
+`AnyKind of_string`
+
+| Function           | Result               |
+|--------------------|----------------------|
+| `ToUpper`          | `ANY KIND OF_STRING` |
+| `ToLower`          | `anykind of_string`  |
+| `ToSnake`          | `any_kind_of_string` |
+| `ToScreamingSnake` | `ANY_KIND_OF_STRING` |
+| `ToKebab`          | `any-kind-of-string` |
+| `ToScreamingKebab` | `ANY-KIND-OF-STRING` |
+| `ToCamel`          | `AnyKindOfString`    |
+| `ToLowerCamel`     | `anyKindOfString`    |
+
+This library uses [Go Template](https://pkg.go.dev/text/template).
+
+so you can use any Go Template syntax like '{{if foo}} .. {{end}}' and like that.
+
 # references
 
 - [example code](./example)
diff --git a/example/CODEGEN.md b/example/CODEGEN.md
index d629230..eaaa698 100644
--- a/example/CODEGEN.md
+++ b/example/CODEGEN.md
@@ -40,6 +40,6 @@ package foo
 import "fmt"
 
 func Bar() {
-	fmt.Println("bar")
+	fmt.Println("{{ .Params.fuga | ToUpper }}")
 }
 ```
diff --git a/go.mod b/go.mod
index 50ecfbf..3762a8c 100644
--- a/go.mod
+++ b/go.mod
@@ -3,6 +3,7 @@ module github.com/igtm/manaita
 go 1.17
 
 require (
+	github.com/iancoleman/strcase v0.2.0
 	github.com/yuin/goldmark v1.4.4
 	github.com/yuin/goldmark-meta v1.0.0
 )
diff --git a/go.sum b/go.sum
index d520cc1..9881311 100644
--- a/go.sum
+++ b/go.sum
@@ -1,3 +1,5 @@
+github.com/iancoleman/strcase v0.2.0 h1:05I4QRnGpI0m37iZQRuskXh+w77mr6Z41lwQzuHLwW0=
+github.com/iancoleman/strcase v0.2.0/go.mod h1:iwCmte+B7n89clKwxIoIXy/HfoL7AsD47ZCWhYzw7ho=
 github.com/yuin/goldmark v1.2.1/go.mod h1:3hX8gzYuyVAZsxl0MRgGTJEmQBFcNTphYh9decYSb74=
 github.com/yuin/goldmark v1.4.4 h1:zNWRjYUW32G9KirMXYHQHVNFkXvMI7LpgNW2AgYAoIs=
 github.com/yuin/goldmark v1.4.4/go.mod h1:rmuwmfZ0+bvzB24eSC//bk1R1Zp3hM0OXYv/G2LIilg=
diff --git a/manaita.go b/manaita.go
index c82f18c..95f0b80 100644
--- a/manaita.go
+++ b/manaita.go
@@ -11,6 +11,7 @@ import (
 	"strings"
 	"text/template"
 
+	"github.com/iancoleman/strcase"
 	"github.com/yuin/goldmark"
 	meta "github.com/yuin/goldmark-meta"
 	"github.com/yuin/goldmark/parser"
@@ -28,6 +29,17 @@ const (
 var (
 	c = flag.String("c", DefaultCodeGenFileName, "template markdown file path")
 	p = flag.String("p", "", "template params")
+
+	funcMap = template.FuncMap{
+		"ToUpper":          strings.ToUpper,
+		"ToLower":          strings.ToLower,
+		"ToSnake":          strcase.ToSnake,
+		"ToScreamingSnake": strcase.ToScreamingSnake,
+		"ToKebab":          strcase.ToKebab,
+		"ToScreamingKebab": strcase.ToScreamingKebab,
+		"ToCamel":          strcase.ToCamel,
+		"ToLowerCamel":     strcase.ToLowerCamel,
+	}
 )
 
 func main() {
@@ -111,7 +123,7 @@ func main() {
 			// dest filename
 			destFileName := strings.Replace(loc, DestFileNameStartCode, "", -1)
 			// compile filename
-			tmpl := template.Must(template.New("").Parse(destFileName))
+			tmpl := template.Must(template.New("").Funcs(funcMap).Parse(destFileName))
 			var compiledDest bytes.Buffer
 			err = tmpl.Execute(&compiledDest, map[string]interface{}{
 				"Env":    envMap,
@@ -137,7 +149,7 @@ func main() {
 						code = GoTemplateHeader + code
 					}
 
-					tmpl := template.Must(template.New("").Parse(code))
+					tmpl := template.Must(template.New("").Funcs(funcMap).Parse(code))
 					err = tmpl.Execute(destFile, map[string]interface{}{
 						"Env":    envMap,
 						"Params": paramMap,