New functions strings.CamelCase and strings.SnakeCase

Signed-off-by: Dave Henderson <dhenderson@gmail.com>

6 files changed, 242 insertions, 3 deletions

diff --git a/docs-src/content/functions/strings.yml b/docs-src/content/functions/strings.yml
index 9359a956..773b7154 100644
--- a/docs-src/content/functions/strings.yml
+++ b/docs-src/content/functions/strings.yml
@@ -42,7 +42,7 @@ funcs:
     description: |
       Surrounds an input string with a single-quote (apostrophe) character (`'`). If the input is not a string, converts first.
 
-      `'` characters in the input are first escaped in the YAML-style (by repetition: `''`).
+      `'` characters in the input are first escaped in the YAML-style (by repetition: `''`).<!-- ' -->
     pipeline: true
     arguments:
       - name: in
@@ -52,5 +52,63 @@ funcs:
       - |
         $ gomplate -i '{{ "in" | squote }}'
         'in'
+      - |
         $ gomplate -i "{{ strings.Squote \"it's a banana\" }}"
         'it''s a banana'
+  - name: strings.CamelCase
+    description: |
+      Converts a sentence to CamelCase, i.e. `The quick brown fox` becomes `TheQuickBrownFox`.
+
+      All non-alphanumeric characters are stripped, and the beginnings of words are upper-cased. If the input begins with a lower-case letter, the result will also begin with a lower-case letter.
+
+      See [CamelCase on Wikipedia](https://en.wikipedia.org/wiki/Camel_case) for more details.
+    pipeline: true
+    arguments:
+      - name: in
+        required: true
+        description: The input
+    examples:
+      - |
+        $ gomplate -i '{{ "Hello, World!" | strings.CamelCase }}'
+        HelloWorld
+      - |
+        $ gomplate -i '{{ "hello jello" | strings.CamelCase }}'
+        helloJello
+  - name: strings.SnakeCase
+    description: |
+      Converts a sentence to snake_case, i.e. `The quick brown fox` becomes `The_quick_brown_fox`.
+
+      All non-alphanumeric characters are stripped, and spaces are replaced with an underscore (`_`). If the input begins with a lower-case letter, the result will also begin with a lower-case letter.
+
+      See [Snake Case on Wikipedia](https://en.wikipedia.org/wiki/Snake_case) for more details.
+    pipeline: true
+    arguments:
+      - name: in
+        required: true
+        description: The input
+    examples:
+      - |
+        $ gomplate -i '{{ "Hello, World!" | strings.SnakeCase }}'
+        Hello_world
+      - |
+        $ gomplate -i '{{ "hello jello" | strings.SnakeCase }}'
+        hello_jello
+  - name: strings.KebabCase
+    description: |
+      Converts a sentence to kebab-case, i.e. `The quick brown fox` becomes `The-quick-brown-fox`.
+
+      All non-alphanumeric characters are stripped, and spaces are replaced with a hyphen (`-`). If the input begins with a lower-case letter, the result will also begin with a lower-case letter.
+
+      See [Kebab Case on Wikipedia](https://en.wikipedia.org/wiki/Kebab_case) for more details.
+    pipeline: true
+    arguments:
+      - name: in
+        required: true
+        description: The input
+    examples:
+      - |
+        $ gomplate -i '{{ "Hello, World!" | strings.KebabCase }}'
+        Hello-world
+      - |
+        $ gomplate -i '{{ "hello jello" | strings.KebabCase }}'
+        hello-jello
diff --git a/docs/content/functions/strings.md b/docs/content/functions/strings.md
index a13ad138..8f019dfa 100644
--- a/docs/content/functions/strings.md
+++ b/docs/content/functions/strings.md
@@ -160,11 +160,11 @@ Returns an alphanumerically-sorted copy of a given string list.
 
 ### Usage
 ```go
-strings.Sort list
+strings.Sort list 
 ```
 
 ```go
-list | strings.Sort
+list | strings.Sort  
 ```
 
 ### Arguments
@@ -355,6 +355,8 @@ in | strings.Squote
 ```console
 $ gomplate -i '{{ "in" | squote }}'
 'in'
+```
+```console
 $ gomplate -i "{{ strings.Squote \"it's a banana\" }}"
 'it''s a banana'
 ```
@@ -528,6 +530,108 @@ $ gomplate -i '{{ "hello, world" | strings.Trunc 5 }}'
 hello
 ```
 
+## `strings.CamelCase`
+
+Converts a sentence to CamelCase, i.e. `The quick brown fox` becomes `TheQuickBrownFox`.
+
+All non-alphanumeric characters are stripped, and the beginnings of words are upper-cased. If the input begins with a lower-case letter, the result will also begin with a lower-case letter.
+
+See [CamelCase on Wikipedia](https://en.wikipedia.org/wiki/Camel_case) for more details.
+
+### Usage
+```go
+strings.CamelCase in 
+```
+
+```go
+in | strings.CamelCase  
+```
+
+### Arguments
+
+| name | description |
+|------|-------------|
+| `in` | _(required)_ The input |
+
+### Examples
+
+```console
+$ gomplate -i '{{ "Hello, World!" | strings.CamelCase }}'
+HelloWorld
+```
+```console
+$ gomplate -i '{{ "hello jello" | strings.CamelCase }}'
+helloJello
+```
+
+## `strings.SnakeCase`
+
+Converts a sentence to snake_case, i.e. `The quick brown fox` becomes `The_quick_brown_fox`.
+
+All non-alphanumeric characters are stripped, and spaces are replaced with an underscore (`_`). If the input begins with a lower-case letter, the result will also begin with a lower-case letter.
+
+See [Snake Case on Wikipedia](https://en.wikipedia.org/wiki/Snake_case) for more details.
+
+### Usage
+```go
+strings.SnakeCase in 
+```
+
+```go
+in | strings.SnakeCase  
+```
+
+### Arguments
+
+| name | description |
+|------|-------------|
+| `in` | _(required)_ The input |
+
+### Examples
+
+```console
+$ gomplate -i '{{ "Hello, World!" | strings.SnakeCase }}'
+Hello_world
+```
+```console
+$ gomplate -i '{{ "hello jello" | strings.SnakeCase }}'
+hello_jello
+```
+
+## `strings.KebabCase`
+
+Converts a sentence to kebab-case, i.e. `The quick brown fox` becomes `The-quick-brown-fox`.
+
+All non-alphanumeric characters are stripped, and spaces are replaced with a hyphen (`-`). If the input begins with a lower-case letter, the result will also begin with a lower-case letter.
+
+See [Kebab Case on Wikipedia](https://en.wikipedia.org/wiki/Kebab_case) for more details.
+
+### Usage
+```go
+strings.KebabCase in 
+```
+
+```go
+in | strings.KebabCase  
+```
+
+### Arguments
+
+| name | description |
+|------|-------------|
+| `in` | _(required)_ The input |
+
+### Examples
+
+```console
+$ gomplate -i '{{ "Hello, World!" | strings.KebabCase }}'
+Hello-world
+```
+```console
+$ gomplate -i '{{ "hello jello" | strings.KebabCase }}'
+hello-jello
+```
+
 ## `contains`
 
 **See [`strings.Contains](#strings-contains) for a pipeline-compatible version**
diff --git a/funcs/strings.go b/funcs/strings.go
index 0bb0924b..de00b4f1 100644
--- a/funcs/strings.go
+++ b/funcs/strings.go
@@ -224,3 +224,18 @@ func (f *StringFuncs) Squote(in interface{}) string {
 	s = strings.Replace(s, `'`, `''`, -1)
 	return fmt.Sprintf("'%s'", s)
 }
+
+// SnakeCase -
+func (f *StringFuncs) SnakeCase(in interface{}) (string, error) {
+	return gompstrings.SnakeCase(conv.ToString(in)), nil
+}
+
+// CamelCase -
+func (f *StringFuncs) CamelCase(in interface{}) (string, error) {
+	return gompstrings.CamelCase(conv.ToString(in)), nil
+}
+
+// KebabCase -
+func (f *StringFuncs) KebabCase(in interface{}) (string, error) {
+	return gompstrings.KebabCase(conv.ToString(in)), nil
+}
diff --git a/strings/strings.go b/strings/strings.go
index 3ee15c61..8c10865a 100644
--- a/strings/strings.go
+++ b/strings/strings.go
@@ -1,6 +1,7 @@
 package strings
 
 import (
+	"regexp"
 	"sort"
 	"strings"
 )
@@ -45,3 +46,38 @@ func Sort(list []string) []string {
 	sorted.Sort()
 	return sorted
 }
+
+var (
+	spaces      = regexp.MustCompile(`\s+`)
+	nonAlphaNum = regexp.MustCompile(`[^\pL\pN]+`)
+)
+
+// SnakeCase -
+func SnakeCase(in string) string {
+	s := casePrepare(in)
+	return spaces.ReplaceAllString(s, "_")
+}
+
+// KebabCase -
+func KebabCase(in string) string {
+	s := casePrepare(in)
+	return spaces.ReplaceAllString(s, "-")
+}
+
+func casePrepare(in string) string {
+	in = strings.TrimSpace(in)
+	s := strings.ToLower(in)
+	// make sure the first letter remains lower- or upper-cased
+	s = strings.Replace(s, string(s[0]), string(in[0]), 1)
+	s = nonAlphaNum.ReplaceAllString(s, " ")
+	return strings.TrimSpace(s)
+}
+
+// CamelCase -
+func CamelCase(in string) string {
+	in = strings.TrimSpace(in)
+	s := strings.Title(in)
+	// make sure the first letter remains lower- or upper-cased
+	s = strings.Replace(s, string(s[0]), string(in[0]), 1)
+	return nonAlphaNum.ReplaceAllString(s, "")
+}
diff --git a/strings/strings_test.go b/strings/strings_test.go
index f2afb2f5..dfcee552 100644
--- a/strings/strings_test.go
+++ b/strings/strings_test.go
@@ -39,3 +39,18 @@ func TestSort(t *testing.T) {
 	expected = []string{"18", "42", "45"}
 	assert.EqualValues(t, expected, Sort(in))
 }
+
+func TestCaseFuncs(t *testing.T) {
+	testdata := []struct{ in, s, k, c string }{
+		{"  Foo bar ", "Foo_bar", "Foo-bar", "FooBar"},
+		{"foo  bar", "foo_bar", "foo-bar", "fooBar"},
+		{" baz\tqux  ", "baz_qux", "baz-qux", "bazQux"},
+		{"Hello, World!", "Hello_world", "Hello-world", "HelloWorld"},
+		{"grüne | Straße", "grüne_straße", "grüne-straße", "grüneStraße"},
+	}
+	for _, d := range testdata {
+		assert.Equal(t, d.s, SnakeCase(d.in))
+		assert.Equal(t, d.k, KebabCase(d.in))
+		assert.Equal(t, d.c, CamelCase(d.in))
+	}
+}
diff --git a/tests/integration/strings_test.go b/tests/integration/strings_test.go
index affd8f32..4b9db835 100644
--- a/tests/integration/strings_test.go
+++ b/tests/integration/strings_test.go
@@ -49,3 +49,14 @@ func (s *StringsSuite) TestSlug(c *C) {
 		`{{ strings.Slug "Hellö, Wôrld! Free @ last..." }}`)
 	result.Assert(c, icmd.Expected{ExitCode: 0, Out: `hello-world-free-at-last`})
 }
+
+func (s *StringsSuite) TestCaseFuncs(c *C) {
+	result := icmd.RunCommand(GomplateBin, "-i",
+		`{{ strings.CamelCase "Hellö, Wôrld! Free @ last..." }}
+{{ strings.SnakeCase "Hellö, Wôrld! Free @ last..." }}
+{{ strings.KebabCase "Hellö, Wôrld! Free @ last..." }}`)
+	result.Assert(c, icmd.Expected{ExitCode: 0, Out: `HellöWôrldFreeLast
+Hellö_wôrld_free_last
+Hellö-wôrld-free-last`})
+
+}