Add "replaceAll" function and documentation

This commit adds a `replaceAll` function which takes three arguments - an
original string, the substring to replace, and the string with which to
replace it. This is of particular use when generating node names from IP
addresses where the node name may not contain "." characters.

4 files changed, 46 insertions, 1 deletions

diff --git a/README.md b/README.md
index 92b8085f..cb60f2c6 100644
--- a/README.md
+++ b/README.md
@@ -46,6 +46,7 @@ Gomplate is an alternative that will let you process templates which also includ
 		- [`slice`](#slice)
 		- [`split`](#split)
 		- [`splitN`](#splitn)
+		- [`replaceAll`](#replaceAll)
 		- [`title`](#title)
 		- [`toLower`](#tolower)
 		- [`toUpper`](#toupper)
@@ -355,6 +356,23 @@ $ gomplate -i '{{ range splitN "foo:bar:baz" ":" 2 }}{{.}}{{end}}'
 foo
 bar:baz
 ```
+#### `replaceAll`
+
+Replaces all occurrences of a given string with another.
+
+##### Example
+
+```console
+$ gomplate -i '{{ replaceAll "." "-" "172.21.1.42" }}'
+172-21-1-42
+```
+
+##### Example (with pipeline)
+
+```console
+$ gomplate -i '{{ "172.21.1.42" | replaceAll "." "-" }}'
+172-21-1-42
+```
 
 #### `title`
 
diff --git a/gomplate.go b/gomplate.go
index 28e623ab..c2490e81 100644
--- a/gomplate.go
+++ b/gomplate.go
@@ -4,7 +4,6 @@ import (
 	"io"
 	"log"
 	"net/url"
-
 	"strings"
 	"text/template"
 
@@ -39,6 +38,7 @@ func (g *Gomplate) RunTemplate(text string, out io.Writer) {
 func NewGomplate(data *Data, leftDelim, rightDelim string) *Gomplate {
 	env := &Env{}
 	typeconv := &TypeConv{}
+	stringfunc := &stringFunc{}
 	ec2meta := aws.NewEc2Meta()
 	ec2info := aws.NewEc2Info()
 	return &Gomplate{
@@ -65,6 +65,7 @@ func NewGomplate(data *Data, leftDelim, rightDelim string) *Gomplate {
 			"contains":         strings.Contains,
 			"hasPrefix":        strings.HasPrefix,
 			"hasSuffix":        strings.HasSuffix,
+			"replaceAll":       stringfunc.replaceAll,
 			"split":            strings.Split,
 			"splitN":           strings.SplitN,
 			"title":            strings.Title,
diff --git a/stringfunc.go b/stringfunc.go
new file mode 100644
index 00000000..ff51b80a
--- /dev/null
+++ b/stringfunc.go
@@ -0,0 +1,10 @@
+package main
+
+import "strings"
+
+// stringFunc - string manipulation function wrappers
+type stringFunc struct{}
+
+func (t stringFunc) replaceAll(old, new, s string) string {
+	return strings.Replace(s, old, new, -1)
+}
diff --git a/stringfunc_test.go b/stringfunc_test.go
new file mode 100644
index 00000000..62d95dcb
--- /dev/null
+++ b/stringfunc_test.go
@@ -0,0 +1,16 @@
+package main
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestReplaceAll(t *testing.T) {
+	sf := &stringFunc{}
+
+	assert.Equal(t, "Replaced",
+		sf.replaceAll("Orig", "Replaced", "Orig"))
+	assert.Equal(t, "ReplacedReplaced",
+		sf.replaceAll("Orig", "Replaced", "OrigOrig"))
+}