From 6ec30747dc7dc1437e91afed388a183685591d50 Mon Sep 17 00:00:00 2001
From: Xopherus <craborg@zerofox.com>
Date: Tue, 12 Feb 2019 10:28:13 -0500
Subject: [PATCH] Add whitespace-separated transformation

---
 README.md                        |  8 +++++---
 endtoend_test.go                 |  3 +++
 stringer.go                      |  4 ++++
 testdata/transform_whitespace.go | 25 +++++++++++++++++++++++++
 4 files changed, 37 insertions(+), 3 deletions(-)
 create mode 100644 testdata/transform_whitespace.go

diff --git a/README.md b/README.md
index 2cebb9f..87df7df 100644
--- a/README.md
+++ b/README.md
@@ -29,6 +29,7 @@ When Enumer is applied to a type, it will generate:
 - When the flag `sql` is provided, the methods for implementing the Scanner and Valuer interfaces will be also generated.
   Useful when storing the enum in a database.
 
+
 For example, if we have an enum type called `Pill`,
 
 ```go
@@ -120,7 +121,7 @@ name := MyTypeValue.String() // name => "MyTypeValue"
 
 Sometimes you need to use some other string representation format than CamelCase (i.e. in JSON).
 
-To transform it from CamelCase to snake_case or kebab-case, you can use the `transform` flag.
+To transform it from CamelCase to another format, you can use the `transform` flag.
 
 For example, the command `enumer -type=MyType -json -transform=snake` would generate the following string representation:
 
@@ -128,7 +129,7 @@ For example, the command `enumer -type=MyType -json -transform=snake` would gene
 name := MyTypeValue.String() // name => "my_type_value"
 ```
 
-**Note**: The transformation only works form CamelCase to snake_case or kebab-case, not the other way around.
+**Note**: The transformation only works from CamelCase to snake_case or kebab-case, not the other way around.
 
 ### Transformers
 
@@ -142,6 +143,7 @@ name := MyTypeValue.String() // name => "my_type_value"
 - first (Use first character of string)
 - first-lower (same as first only lower case)
 - first-upper (same as first only upper case)
+- whitespace
 
 ## How to use
 
@@ -152,7 +154,7 @@ There are four boolean flags: `json`, `text`, `yaml` and `sql`. You can use any
 
 For enum string representation transformation the `transform` and `trimprefix` flags
 were added (i.e. `enumer -type=MyType -json -transform=snake`).
-Possible transform values are `snake` and `kebab` for transformation to snake_case and kebab-case accordingly.
+Possible transform values are listed above in the [transformers](#transformers) section.
 The default value for `transform` flag is `noop` which means no transformation will be performed.
 
 If a prefix is provided via the `trimprefix` flag, it will be trimmed from the start of each name (before
diff --git a/endtoend_test.go b/endtoend_test.go
index 10e0e39..5629e33 100644
--- a/endtoend_test.go
+++ b/endtoend_test.go
@@ -93,6 +93,9 @@ func TestEndToEnd(t *testing.T) {
 		case "transform_first_lower.go":
 			typeName = "FirstLowerCaseValue"
 			transformNameMethod = "first-lower"
+		case "transform_whitespace.go":
+			typeName = "WhitespaceSeparatedValue"
+			transformNameMethod = "whitespace"
 		default:
 			typeName = fmt.Sprintf("%c%s", name[0]+'A'-'a', name[1:len(name)-len(".go")])
 			transformNameMethod = "noop"
diff --git a/stringer.go b/stringer.go
index e3ac91c..a57501d 100644
--- a/stringer.go
+++ b/stringer.go
@@ -286,6 +286,10 @@ func (g *Generator) transformValueNames(values []Value, transformMethod string)
 			r, _ := utf8.DecodeRuneInString(s)
 			return strings.ToLower(string(r))
 		}
+	case "whitespace":
+		fn = func(s string) string {
+			return strings.ToLower(name.Delimit(s, ' '))
+		}
 	default:
 		return
 	}
diff --git a/testdata/transform_whitespace.go b/testdata/transform_whitespace.go
new file mode 100644
index 0000000..b3d552d
--- /dev/null
+++ b/testdata/transform_whitespace.go
@@ -0,0 +1,25 @@
+package main
+
+import "fmt"
+
+type WhitespaceSeparatedValue int
+
+const (
+	WhitespaceSeparatedValueOne WhitespaceSeparatedValue = iota
+	WhitespaceSeparatedValueTwo
+	WhitespaceSeparatedValueThree
+)
+
+func main() {
+	ck(WhitespaceSeparatedValueOne, "whitespace separated value one")
+	ck(WhitespaceSeparatedValueTwo, "whitespace separated value two")
+	ck(WhitespaceSeparatedValueThree, "whitespace separated value three")
+	ck(-127, "WhitespaceSeparatedValue(-127)")
+	ck(127, "WhitespaceSeparatedValue(127)")
+}
+
+func ck(value WhitespaceSeparatedValue, str string) {
+	if fmt.Sprint(value) != str {
+		panic("transform_whitespace.go: " + str)
+	}
+}