Merging in serjlee

README.md

@@ -1,32 +1,36 @@
 # Enumer [![GoDoc](https://godoc.org/github.com/alvaroloes/enumer?status.svg)](https://godoc.org/github.com/alvaroloes/enumer) [![Go Report Card](https://goreportcard.com/badge/github.com/alvaroloes/enumer)](https://goreportcard.com/report/github.com/alvaroloes/enumer) [![cover.run go](https://cover.run/go/github.com/alvaroloes/enumer.svg?tag=golang-1.10)](https://cover.run/go/github.com/alvaroloes/enumer?tag=golang-1.10)
+
 Enumer is a tool to generate Go code that adds useful methods to Go enums (constants with a specific type).
 It started as a fork of [Rob Pike’s Stringer tool](https://godoc.org/golang.org/x/tools/cmd/stringer).
 
 ## Generated functions and methods
+
 When Enumer is applied to a type, it will generate:
 
-* The following basic methods/functions: 
+- The following basic methods/functions:
 
-  * Method `String()`: returns the string representation of the enum value. This makes the enum conform
+  - Method `String()`: returns the string representation of the enum value. This makes the enum conform
-the `Stringer` interface, so whenever you print an enum value, you'll get the string name instead of a number.
+    the `Stringer` interface, so whenever you print an enum value, you'll get the string name instead of a number.
-  * Function `<Type>String(s string)`: returns the enum value from its string representation. This is useful
+  - Function `<Type>String(s string)`: returns the enum value from its string representation. This is useful
-when you need to read enum values from command line arguments, from a configuration file, or
+    when you need to read enum values from command line arguments, from a configuration file, or
-from a REST API request... In short, from those places where using the real enum value (an integer) would
+    from a REST API request... In short, from those places where using the real enum value (an integer) would
-be almost meaningless or hard to trace or use by a human.
+    be almost meaningless or hard to trace or use by a human.
-  * Function `<Type>Values()`: returns a slice with all the values of the enum
+  - Function `<Type>Values()`: returns a slice with all the values of the enum
-  * Method `IsA<Type>()`: returns true only if the current value is among the values of the enum. Useful for validations.
+  - Method `IsA<Type>()`: returns true only if the current value is among the values of the enum. Useful for validations.
-* When the flag `json` is provided, two additional methods will be generated, `MarshalJSON()` and `UnmarshalJSON()`. These make
+
-the enum conform to the `json.Marshaler` and `json.Unmarshaler` interfaces. Very useful to use it in JSON APIs.
+- When the flag `json` is provided, two additional methods will be generated, `MarshalJSON()` and `UnmarshalJSON()`. These make
-* When the flag `text` is provided, two additional methods will be generated, `MarshalText()` and `UnmarshalText()`. These make
+  the enum conform to the `json.Marshaler` and `json.Unmarshaler` interfaces. Very useful to use it in JSON APIs.
-the enum conform to the `encoding.TextMarshaler` and `encoding.TextUnmarshaler` interfaces. 
+- When the flag `text` is provided, two additional methods will be generated, `MarshalText()` and `UnmarshalText()`. These make
-**Note:** If you use your enum values as keys in a map and you encode the map as _JSON_, you need this flag set to true to properly
+  the enum conform to the `encoding.TextMarshaler` and `encoding.TextUnmarshaler` interfaces.
-convert the map keys to json (strings). If not, the numeric values will be used instead
+  **Note:** If you use your enum values as keys in a map and you encode the map as _JSON_, you need this flag set to true to properly
-* When the flag `yaml` is provided, two additional methods will be generated, `MarshalYAML()` and `UnmarshalYAML()`. These make
+  convert the map keys to json (strings). If not, the numeric values will be used instead
-the enum conform to the `gopkg.in/yaml.v2.Marshaler` and `gopkg.in/yaml.v2.Unmarshaler` interfaces.
+- When the flag `yaml` is provided, two additional methods will be generated, `MarshalYAML()` and `UnmarshalYAML()`. These make
-* When the flag `sql` is provided, the methods for implementing the Scanner and Valuer interfaces will be also generated.
+  the enum conform to the `gopkg.in/yaml.v2.Marshaler` and `gopkg.in/yaml.v2.Unmarshaler` interfaces.
-Useful when storing the enum in a database.
+- 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
 type Pill int
 
@@ -38,21 +42,23 @@ const (
 	Acetaminophen = Paracetamol
 )
 ```
+
 executing `enumer -type=Pill -json` will generate a new file with four basic methods and two extra for JSON:
+
 ```go
-func (i Pill) String() string { 
+func (i Pill) String() string {
 	//...
 }
 
-func PillString(s string) (Pill, error) { 
+func PillString(s string) (Pill, error) {
 	//...
 }
 
-func PillValues() []Pill { 
+func PillValues() []Pill {
 	//...
 }
 
-func (i Pill) IsAPill() bool { 
+func (i Pill) IsAPill() bool {
 	//...
 }
 
@@ -64,7 +70,9 @@ func (i *Pill) UnmarshalJSON(data []byte) error {
 	//...
 }
 ```
+
 From now on, we can:
+
 ```go
 // Convert any Pill value to string
 var aspirinString string = Aspirin.String()
@@ -119,15 +127,30 @@ For example, the command `enumer -type=MyType -json -transform=snake` would gene
 ```go
 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.
 
+### Transformers
+
+- snake
+- snake-upper
+- kebab
+- kebab-upper
+- lower (lowercase)
+- upper (UPPERCASE)
+- title (TitleCase)
+- title-lower (titleCase)
+- first (Use first character of string)
+- first-lower (same as first only lower case)
+- first-upper (same as first only upper case)
+
 ## How to use
+
 The usage of Enumer is the same as Stringer, so you can refer to the [Stringer docs](https://godoc.org/golang.org/x/tools/cmd/stringer)
 for more information.
 
 There are four boolean flags: `json`, `text`, `yaml` and `sql`. You can use any combination of them (i.e. `enumer -type=Pill -json -text`),
 
-
 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.
@@ -136,6 +159,9 @@ The default value for `transform` flag is `noop` which means no transformation w
 If a prefix is provided via the `trimprefix` flag, it will be trimmed from the start of each name (before
 it is transformed). If a name doesn't have the prefix it will be passed unchanged.
 
+If a prefix is provided via the `addprefix` flag, it will be added to the start of each name (after trimming and after transforming).
+
 ## Inspiring projects
-* [Stringer](https://godoc.org/golang.org/x/tools/cmd/stringer)
+
-* [jsonenums](https://github.com/campoy/jsonenums)
+- [Stringer](https://godoc.org/golang.org/x/tools/cmd/stringer)
+- [jsonenums](https://github.com/campoy/jsonenums)

endtoend_test.go

@@ -72,13 +72,45 @@ func TestEndToEnd(t *testing.T) {
 			t.Logf("cgo is no enabled for %s", name)
 			continue
 		}
-		// Names are known to be ASCII and long enough.
-		typeName := fmt.Sprintf("%c%s", name[0]+'A'-'a', name[1:len(name)-len(".go")])
-		transformNameMethod := "noop"
 
-		if name == "transform.go" {
+		// Names are known to be ASCII and long enough.
-			typeName = "CamelCaseValue"
+		var typeName string
+		var transformNameMethod string
+
+		switch name {
+		case "transform_snake.go":
+			typeName = "SnakeCaseValue"
 			transformNameMethod = "snake"
+		case "transform_snake_upper.go":
+			typeName = "SnakeUpperCaseValue"
+			transformNameMethod = "snake-upper"
+		case "transform_kebab.go":
+			typeName = "KebabCaseValue"
+			transformNameMethod = "kebab"
+		case "transform_kebab_upper.go":
+			typeName = "KebabUpperCaseValue"
+			transformNameMethod = "kebab-upper"
+		case "transform_upper.go":
+			typeName = "UpperCaseValue"
+			transformNameMethod = "upper"
+		case "transform_lower.go":
+			typeName = "LowerCaseValue"
+			transformNameMethod = "lower"
+		case "transform_title.go":
+			typeName = "TitleCaseValue"
+			transformNameMethod = "title"
+		case "transform_first.go":
+			typeName = "FirstCaseValue"
+			transformNameMethod = "first"
+		case "transform_first_upper.go":
+			typeName = "FirstUpperCaseValue"
+			transformNameMethod = "first-upper"
+		case "transform_first_lower.go":
+			typeName = "FirstLowerCaseValue"
+			transformNameMethod = "first-lower"
+		default:
+			typeName = fmt.Sprintf("%c%s", name[0]+'A'-'a', name[1:len(name)-len(".go")])
+			transformNameMethod = "noop"
 		}
 
 		stringerCompileAndRun(t, dir, stringer, typeName, name, transformNameMethod)

enumer.go

@@ -22,6 +22,16 @@ func %[1]sValues() []%[1]s {
 }
 `
 
+// Arguments to format are:
+//	[1]: type name
+const stringsMethod = `// %[1]sStrings returns a slice of all String values of the enum
+func %[1]sStrings() []string {
+	strs := make([]string, len(_%[1]sNames))
+	copy(strs, _%[1]sNames)
+	return strs
+}
+`
+
 // Arguments to format are:
 //	[1]: type name
 const stringBelongsMethodLoop = `// IsA%[1]s returns "true" if the value is listed in the enum definition. "false" otherwise
@@ -57,8 +67,26 @@ func (g *Generator) buildBasicExtras(runs [][]Value, typeName string, runsThresh
 	g.Printf("}\n\n")
 
 	// Print the map between name and value
-	g.Printf("\nvar _%sNameToValueMap = map[string]%s{\n", typeName, typeName)
+	g.printValueMap(runs, typeName, runsThreshold)
+
+	// Print the slice of names
+	g.printNamesSlice(runs, typeName, runsThreshold)
+
+	// Print the basic extra methods
+	g.Printf(stringNameToValueMethod, typeName)
+	g.Printf(stringValuesMethod, typeName)
+	g.Printf(stringsMethod, typeName)
+	if len(runs) < runsThreshold {
+		g.Printf(stringBelongsMethodLoop, typeName)
+	} else { // There is a map of values, the code is simpler then
+		g.Printf(stringBelongsMethodSet, typeName)
+	}
+}
+
+func (g *Generator) printValueMap(runs [][]Value, typeName string, runsThreshold int) {
 	thereAreRuns := len(runs) > 1 && len(runs) <= runsThreshold
+	g.Printf("\nvar _%sNameToValueMap = map[string]%s{\n", typeName, typeName)
+
 	var n int
 	var runID string
 	for i, values := range runs {
@@ -75,15 +103,27 @@ func (g *Generator) buildBasicExtras(runs [][]Value, typeName string, runsThresh
 		}
 	}
 	g.Printf("}\n\n")
+}
+func (g *Generator) printNamesSlice(runs [][]Value, typeName string, runsThreshold int) {
+	thereAreRuns := len(runs) > 1 && len(runs) <= runsThreshold
+	g.Printf("\nvar _%sNames = []string{\n", typeName)
 
-	// Print the basic extra methods
+	var n int
-	g.Printf(stringNameToValueMethod, typeName)
+	var runID string
-	g.Printf(stringValuesMethod, typeName)
+	for i, values := range runs {
-	if len(runs) < runsThreshold {
+		if thereAreRuns {
-		g.Printf(stringBelongsMethodLoop, typeName)
+			runID = "_" + fmt.Sprintf("%d", i)
-	} else { // There is a map of values, the code is simpler then
+			n = 0
-		g.Printf(stringBelongsMethodSet, typeName)
+		} else {
+			runID = ""
+		}
+
+		for _, value := range values {
+			g.Printf("\t_%sName%s[%d:%d],\n", typeName, runID, n, n+len(value.name))
+			n += len(value.name)
+		}
 	}
+	g.Printf("}\n\n")
 }
 
 // Arguments to format are:

golden_test.go

@@ -52,8 +52,16 @@ var goldenJSONAndSQL = []Golden{
 	{"prime", primeJsonAndSqlIn, primeJsonAndSqlOut},
 }
 
-var goldenPrefix = []Golden{
+var goldenTrimPrefix = []Golden{
-	{"prefix", prefixIn, dayOut},
+	{"trim prefix", trimPrefixIn, dayOut},
+}
+
+var goldenWithPrefix = []Golden{
+	{"with prefix", dayIn, prefixedDayOut},
+}
+
+var goldenTrimAndAddPrefix = []Golden{
+	{"trim and add prefix", trimPrefixIn, trimmedPrefixedDayOut},
 }
 
 // Each example starts with "type XXX [u]int", with a single space separating them.
@@ -95,6 +103,16 @@ var _DayNameToValueMap = map[string]Day{
 	_DayName[44:50]: 6,
 }
 
+var _DayNames = []string{
+	_DayName[0:6],
+	_DayName[6:13],
+	_DayName[13:22],
+	_DayName[22:30],
+	_DayName[30:36],
+	_DayName[36:44],
+	_DayName[44:50],
+}
+
 // DayString retrieves an enum value from the enum constants string name.
 // Throws an error if the param is not part of the enum.
 func DayString(s string) (Day, error) {
@@ -109,6 +127,145 @@ func DayValues() []Day {
 	return _DayValues
 }
 
+// DayStrings returns a slice of all String values of the enum
+func DayStrings() []string {
+	strs := make([]string, len(_DayNames))
+	copy(strs, _DayNames)
+	return strs
+}
+
+// IsADay returns "true" if the value is listed in the enum definition. "false" otherwise
+func (i Day) IsADay() bool {
+	for _, v := range _DayValues {
+		if i == v {
+			return true
+		}
+	}
+	return false
+}
+`
+
+const prefixedDayOut = `
+const _DayName = "DayMondayDayTuesdayDayWednesdayDayThursdayDayFridayDaySaturdayDaySunday"
+
+var _DayIndex = [...]uint8{0, 9, 19, 31, 42, 51, 62, 71}
+
+func (i Day) String() string {
+	if i < 0 || i >= Day(len(_DayIndex)-1) {
+		return fmt.Sprintf("Day(%d)", i)
+	}
+	return _DayName[_DayIndex[i]:_DayIndex[i+1]]
+}
+
+var _DayValues = []Day{0, 1, 2, 3, 4, 5, 6}
+
+var _DayNameToValueMap = map[string]Day{
+	_DayName[0:9]:   0,
+	_DayName[9:19]:  1,
+	_DayName[19:31]: 2,
+	_DayName[31:42]: 3,
+	_DayName[42:51]: 4,
+	_DayName[51:62]: 5,
+	_DayName[62:71]: 6,
+}
+
+var _DayNames = []string{
+	_DayName[0:9],
+	_DayName[9:19],
+	_DayName[19:31],
+	_DayName[31:42],
+	_DayName[42:51],
+	_DayName[51:62],
+	_DayName[62:71],
+}
+
+// DayString retrieves an enum value from the enum constants string name.
+// Throws an error if the param is not part of the enum.
+func DayString(s string) (Day, error) {
+	if val, ok := _DayNameToValueMap[s]; ok {
+		return val, nil
+	}
+	return 0, fmt.Errorf("%s does not belong to Day values", s)
+}
+
+// DayValues returns all values of the enum
+func DayValues() []Day {
+	return _DayValues
+}
+
+// DayStrings returns a slice of all String values of the enum
+func DayStrings() []string {
+	strs := make([]string, len(_DayNames))
+	copy(strs, _DayNames)
+	return strs
+}
+
+// IsADay returns "true" if the value is listed in the enum definition. "false" otherwise
+func (i Day) IsADay() bool {
+	for _, v := range _DayValues {
+		if i == v {
+			return true
+		}
+	}
+	return false
+}
+`
+
+const trimmedPrefixedDayOut = `
+const _DayName = "NightMondayNightTuesdayNightWednesdayNightThursdayNightFridayNightSaturdayNightSunday"
+
+var _DayIndex = [...]uint8{0, 11, 23, 37, 50, 61, 74, 85}
+
+func (i Day) String() string {
+	if i < 0 || i >= Day(len(_DayIndex)-1) {
+		return fmt.Sprintf("Day(%d)", i)
+	}
+	return _DayName[_DayIndex[i]:_DayIndex[i+1]]
+}
+
+var _DayValues = []Day{0, 1, 2, 3, 4, 5, 6}
+
+var _DayNameToValueMap = map[string]Day{
+	_DayName[0:11]:  0,
+	_DayName[11:23]: 1,
+	_DayName[23:37]: 2,
+	_DayName[37:50]: 3,
+	_DayName[50:61]: 4,
+	_DayName[61:74]: 5,
+	_DayName[74:85]: 6,
+}
+
+var _DayNames = []string{
+	_DayName[0:11],
+	_DayName[11:23],
+	_DayName[23:37],
+	_DayName[37:50],
+	_DayName[50:61],
+	_DayName[61:74],
+	_DayName[74:85],
+}
+
+// DayString retrieves an enum value from the enum constants string name.
+// Throws an error if the param is not part of the enum.
+func DayString(s string) (Day, error) {
+	if val, ok := _DayNameToValueMap[s]; ok {
+		return val, nil
+	}
+	return 0, fmt.Errorf("%s does not belong to Day values", s)
+}
+
+// DayValues returns all values of the enum
+func DayValues() []Day {
+	return _DayValues
+}
+
+// DayStrings returns a slice of all String values of the enum
+func DayStrings() []string {
+	strs := make([]string, len(_DayNames))
+	copy(strs, _DayNames)
+	return strs
+}
+
 // IsADay returns "true" if the value is listed in the enum definition. "false" otherwise
 func (i Day) IsADay() bool {
 	for _, v := range _DayValues {
@@ -153,6 +310,12 @@ var _NumberNameToValueMap = map[string]Number{
 	_NumberName[6:11]: 3,
 }
 
+var _NumberNames = []string{
+	_NumberName[0:3],
+	_NumberName[3:6],
+	_NumberName[6:11],
+}
+
 // NumberString retrieves an enum value from the enum constants string name.
 // Throws an error if the param is not part of the enum.
 func NumberString(s string) (Number, error) {
@@ -167,6 +330,13 @@ func NumberValues() []Number {
 	return _NumberValues
 }
 
+// NumberStrings returns a slice of all String values of the enum
+func NumberStrings() []string {
+	strs := make([]string, len(_NumberNames))
+	copy(strs, _NumberNames)
+	return strs
+}
+
 // IsANumber returns "true" if the value is listed in the enum definition. "false" otherwise
 func (i Number) IsANumber() bool {
 	for _, v := range _NumberValues {
@@ -233,6 +403,17 @@ var _GapNameToValueMap = map[string]Gap{
 	_GapName_2[0:6]:   11,
 }
 
+var _GapNames = []string{
+	_GapName_0[0:3],
+	_GapName_0[3:8],
+	_GapName_1[0:4],
+	_GapName_1[4:7],
+	_GapName_1[7:12],
+	_GapName_1[12:17],
+	_GapName_1[17:21],
+	_GapName_2[0:6],
+}
+
 // GapString retrieves an enum value from the enum constants string name.
 // Throws an error if the param is not part of the enum.
 func GapString(s string) (Gap, error) {
@@ -247,6 +428,13 @@ func GapValues() []Gap {
 	return _GapValues
 }
 
+// GapStrings returns a slice of all String values of the enum
+func GapStrings() []string {
+	strs := make([]string, len(_GapNames))
+	copy(strs, _GapNames)
+	return strs
+}
+
 // IsAGap returns "true" if the value is listed in the enum definition. "false" otherwise
 func (i Gap) IsAGap() bool {
 	for _, v := range _GapValues {
@@ -292,6 +480,14 @@ var _NumNameToValueMap = map[string]Num{
 	_NumName[10:12]: 2,
 }
 
+var _NumNames = []string{
+	_NumName[0:3],
+	_NumName[3:6],
+	_NumName[6:8],
+	_NumName[8:10],
+	_NumName[10:12],
+}
+
 // NumString retrieves an enum value from the enum constants string name.
 // Throws an error if the param is not part of the enum.
 func NumString(s string) (Num, error) {
@@ -306,6 +502,13 @@ func NumValues() []Num {
 	return _NumValues
 }
 
+// NumStrings returns a slice of all String values of the enum
+func NumStrings() []string {
+	strs := make([]string, len(_NumNames))
+	copy(strs, _NumNames)
+	return strs
+}
+
 // IsANum returns "true" if the value is listed in the enum definition. "false" otherwise
 func (i Num) IsANum() bool {
 	for _, v := range _NumValues {
@@ -364,6 +567,14 @@ var _UnumNameToValueMap = map[string]Unum{
 	_UnumName_1[3:6]: 254,
 }
 
+var _UnumNames = []string{
+	_UnumName_0[0:2],
+	_UnumName_0[2:4],
+	_UnumName_0[4:6],
+	_UnumName_1[0:3],
+	_UnumName_1[3:6],
+}
+
 // UnumString retrieves an enum value from the enum constants string name.
 // Throws an error if the param is not part of the enum.
 func UnumString(s string) (Unum, error) {
@@ -378,6 +589,13 @@ func UnumValues() []Unum {
 	return _UnumValues
 }
 
+// UnumStrings returns a slice of all String values of the enum
+func UnumStrings() []string {
+	strs := make([]string, len(_UnumNames))
+	copy(strs, _UnumNames)
+	return strs
+}
+
 // IsAUnum returns "true" if the value is listed in the enum definition. "false" otherwise
 func (i Unum) IsAUnum() bool {
 	for _, v := range _UnumValues {
@@ -454,6 +672,22 @@ var _PrimeNameToValueMap = map[string]Prime{
 	_PrimeName[32:35]: 43,
 }
 
+var _PrimeNames = []string{
+	_PrimeName[0:2],
+	_PrimeName[2:4],
+	_PrimeName[4:6],
+	_PrimeName[6:8],
+	_PrimeName[8:11],
+	_PrimeName[11:14],
+	_PrimeName[14:17],
+	_PrimeName[17:20],
+	_PrimeName[20:23],
+	_PrimeName[23:26],
+	_PrimeName[26:29],
+	_PrimeName[29:32],
+	_PrimeName[32:35],
+}
+
 // PrimeString retrieves an enum value from the enum constants string name.
 // Throws an error if the param is not part of the enum.
 func PrimeString(s string) (Prime, error) {
@@ -468,6 +702,13 @@ func PrimeValues() []Prime {
 	return _PrimeValues
 }
 
+// PrimeStrings returns a slice of all String values of the enum
+func PrimeStrings() []string {
+	strs := make([]string, len(_PrimeNames))
+	copy(strs, _PrimeNames)
+	return strs
+}
+
 // IsAPrime returns "true" if the value is listed in the enum definition. "false" otherwise
 func (i Prime) IsAPrime() bool {
 	_, ok := _PrimeMap[i]
@@ -537,6 +778,22 @@ var _PrimeNameToValueMap = map[string]Prime{
 	_PrimeName[32:35]: 43,
 }
 
+var _PrimeNames = []string{
+	_PrimeName[0:2],
+	_PrimeName[2:4],
+	_PrimeName[4:6],
+	_PrimeName[6:8],
+	_PrimeName[8:11],
+	_PrimeName[11:14],
+	_PrimeName[14:17],
+	_PrimeName[17:20],
+	_PrimeName[20:23],
+	_PrimeName[23:26],
+	_PrimeName[26:29],
+	_PrimeName[29:32],
+	_PrimeName[32:35],
+}
+
 // PrimeString retrieves an enum value from the enum constants string name.
 // Throws an error if the param is not part of the enum.
 func PrimeString(s string) (Prime, error) {
@@ -551,6 +808,13 @@ func PrimeValues() []Prime {
 	return _PrimeValues
 }
 
+// PrimeStrings returns a slice of all String values of the enum
+func PrimeStrings() []string {
+	strs := make([]string, len(_PrimeNames))
+	copy(strs, _PrimeNames)
+	return strs
+}
+
 // IsAPrime returns "true" if the value is listed in the enum definition. "false" otherwise
 func (i Prime) IsAPrime() bool {
 	_, ok := _PrimeMap[i]
@@ -638,6 +902,22 @@ var _PrimeNameToValueMap = map[string]Prime{
 	_PrimeName[32:35]: 43,
 }
 
+var _PrimeNames = []string{
+	_PrimeName[0:2],
+	_PrimeName[2:4],
+	_PrimeName[4:6],
+	_PrimeName[6:8],
+	_PrimeName[8:11],
+	_PrimeName[11:14],
+	_PrimeName[14:17],
+	_PrimeName[17:20],
+	_PrimeName[20:23],
+	_PrimeName[23:26],
+	_PrimeName[26:29],
+	_PrimeName[29:32],
+	_PrimeName[32:35],
+}
+
 // PrimeString retrieves an enum value from the enum constants string name.
 // Throws an error if the param is not part of the enum.
 func PrimeString(s string) (Prime, error) {
@@ -652,6 +932,13 @@ func PrimeValues() []Prime {
 	return _PrimeValues
 }
 
+// PrimeStrings returns a slice of all String values of the enum
+func PrimeStrings() []string {
+	strs := make([]string, len(_PrimeNames))
+	copy(strs, _PrimeNames)
+	return strs
+}
+
 // IsAPrime returns "true" if the value is listed in the enum definition. "false" otherwise
 func (i Prime) IsAPrime() bool {
 	_, ok := _PrimeMap[i]
@@ -734,6 +1021,22 @@ var _PrimeNameToValueMap = map[string]Prime{
 	_PrimeName[32:35]: 43,
 }
 
+var _PrimeNames = []string{
+	_PrimeName[0:2],
+	_PrimeName[2:4],
+	_PrimeName[4:6],
+	_PrimeName[6:8],
+	_PrimeName[8:11],
+	_PrimeName[11:14],
+	_PrimeName[14:17],
+	_PrimeName[17:20],
+	_PrimeName[20:23],
+	_PrimeName[23:26],
+	_PrimeName[26:29],
+	_PrimeName[29:32],
+	_PrimeName[32:35],
+}
+
 // PrimeString retrieves an enum value from the enum constants string name.
 // Throws an error if the param is not part of the enum.
 func PrimeString(s string) (Prime, error) {
@@ -748,6 +1051,13 @@ func PrimeValues() []Prime {
 	return _PrimeValues
 }
 
+// PrimeStrings returns a slice of all String values of the enum
+func PrimeStrings() []string {
+	strs := make([]string, len(_PrimeNames))
+	copy(strs, _PrimeNames)
+	return strs
+}
+
 // IsAPrime returns "true" if the value is listed in the enum definition. "false" otherwise
 func (i Prime) IsAPrime() bool {
 	_, ok := _PrimeMap[i]
@@ -835,6 +1145,22 @@ var _PrimeNameToValueMap = map[string]Prime{
 	_PrimeName[32:35]: 43,
 }
 
+var _PrimeNames = []string{
+	_PrimeName[0:2],
+	_PrimeName[2:4],
+	_PrimeName[4:6],
+	_PrimeName[6:8],
+	_PrimeName[8:11],
+	_PrimeName[11:14],
+	_PrimeName[14:17],
+	_PrimeName[17:20],
+	_PrimeName[20:23],
+	_PrimeName[23:26],
+	_PrimeName[26:29],
+	_PrimeName[29:32],
+	_PrimeName[32:35],
+}
+
 // PrimeString retrieves an enum value from the enum constants string name.
 // Throws an error if the param is not part of the enum.
 func PrimeString(s string) (Prime, error) {
@@ -849,6 +1175,13 @@ func PrimeValues() []Prime {
 	return _PrimeValues
 }
 
+// PrimeStrings returns a slice of all String values of the enum
+func PrimeStrings() []string {
+	strs := make([]string, len(_PrimeNames))
+	copy(strs, _PrimeNames)
+	return strs
+}
+
 // IsAPrime returns "true" if the value is listed in the enum definition. "false" otherwise
 func (i Prime) IsAPrime() bool {
 	_, ok := _PrimeMap[i]
@@ -947,6 +1280,22 @@ var _PrimeNameToValueMap = map[string]Prime{
 	_PrimeName[32:35]: 43,
 }
 
+var _PrimeNames = []string{
+	_PrimeName[0:2],
+	_PrimeName[2:4],
+	_PrimeName[4:6],
+	_PrimeName[6:8],
+	_PrimeName[8:11],
+	_PrimeName[11:14],
+	_PrimeName[14:17],
+	_PrimeName[17:20],
+	_PrimeName[20:23],
+	_PrimeName[23:26],
+	_PrimeName[26:29],
+	_PrimeName[29:32],
+	_PrimeName[32:35],
+}
+
 // PrimeString retrieves an enum value from the enum constants string name.
 // Throws an error if the param is not part of the enum.
 func PrimeString(s string) (Prime, error) {
@@ -961,6 +1310,13 @@ func PrimeValues() []Prime {
 	return _PrimeValues
 }
 
+// PrimeStrings returns a slice of all String values of the enum
+func PrimeStrings() []string {
+	strs := make([]string, len(_PrimeNames))
+	copy(strs, _PrimeNames)
+	return strs
+}
+
 // IsAPrime returns "true" if the value is listed in the enum definition. "false" otherwise
 func (i Prime) IsAPrime() bool {
 	_, ok := _PrimeMap[i]
@@ -1013,7 +1369,7 @@ func (i *Prime) Scan(value interface{}) error {
 }
 `
 
-const prefixIn = `type Day int
+const trimPrefixIn = `type Day int
 const (
 	DayMonday Day = iota
 	DayTuesday
@@ -1027,29 +1383,35 @@ const (
 
 func TestGolden(t *testing.T) {
 	for _, test := range golden {
-		runGoldenTest(t, test, false, false, false, false, "")
+		runGoldenTest(t, test, false, false, false, false, "", "")
 	}
 	for _, test := range goldenJSON {
-		runGoldenTest(t, test, true, false, false, false, "")
+		runGoldenTest(t, test, true, false, false, false, "", "")
 	}
 	for _, test := range goldenText {
-		runGoldenTest(t, test, false, false, false, true, "")
+		runGoldenTest(t, test, false, false, false, true, "", "")
 	}
 	for _, test := range goldenYAML {
-		runGoldenTest(t, test, false, true, false, false, "")
+		runGoldenTest(t, test, false, true, false, false, "", "")
 	}
 	for _, test := range goldenSQL {
-		runGoldenTest(t, test, false, false, true, false, "")
+		runGoldenTest(t, test, false, false, true, false, "", "")
 	}
 	for _, test := range goldenJSONAndSQL {
-		runGoldenTest(t, test, true, false, true, false, "")
+		runGoldenTest(t, test, true, false, true, false, "", "")
 	}
-	for _, test := range goldenPrefix {
+	for _, test := range goldenTrimPrefix {
-		runGoldenTest(t, test, false, false, false, false, "Day")
+		runGoldenTest(t, test, false, false, false, false, "Day", "")
+	}
+	for _, test := range goldenWithPrefix {
+		runGoldenTest(t, test, false, false, false, false, "", "Day")
+	}
+	for _, test := range goldenTrimAndAddPrefix {
+		runGoldenTest(t, test, false, false, false, false, "Day", "Night")
 	}
 }
 
-func runGoldenTest(t *testing.T, test Golden, generateJSON, generateYAML, generateSQL, generateText bool, prefix string) {
+func runGoldenTest(t *testing.T, test Golden, generateJSON, generateYAML, generateSQL, generateText bool, trimPrefix string, prefix string) {
 	var g Generator
 	file := test.name + ".go"
 	input := "package test\n" + test.input
@@ -1076,9 +1438,14 @@ func runGoldenTest(t *testing.T, test Golden, generateJSON, generateYAML, genera
 	if len(tokens) != 3 {
 		t.Fatalf("%s: need type declaration on first line", test.name)
 	}
-	g.generate(tokens[1], generateJSON, generateYAML, generateSQL, generateText, "noop", prefix)
+	g.generate(tokens[1], generateJSON, generateYAML, generateSQL, generateText, "noop", trimPrefix, prefix)
 	got := string(g.format())
 	if got != test.output {
+		// dmp := diffmatchpatch.New()
+
+		// diffs := dmp.DiffMain(got, test.output, false)
+
+		// t.Errorf(dmp.DiffPrettyText(diffs))
 		t.Errorf("%s: got\n====\n%s====\nexpected\n====%s", test.name, got, test.output)
 	}
 }

stringer.go

@@ -24,6 +24,8 @@ import (
 	"path/filepath"
 	"sort"
 	"strings"
+	"unicode"
+	"unicode/utf8"
 
 	"golang.org/x/tools/go/packages"
 
@@ -50,6 +52,7 @@ var (
 	output          = flag.String("output", "", "output file name; default srcdir/<type>_string.go")
 	transformMethod = flag.String("transform", "noop", "enum item name transformation method. Default: noop")
 	trimPrefix      = flag.String("trimprefix", "", "transform each item name by removing a prefix. Default: \"\"")
+	addPrefix       = flag.String("addprefix", "", "transform each item name by adding a prefix. Default: \"\"")
 )
 
 var comments arrayFlags
@@ -122,7 +125,7 @@ func main() {
 
 	// Run generate for each type.
 	for _, typeName := range typs {
-		g.generate(typeName, *json, *yaml, *sql, *text, *transformMethod, *trimPrefix)
+		g.generate(typeName, *json, *yaml, *sql, *text, *transformMethod, *trimPrefix, *addPrefix)
 	}
 
 	// Format the output.
@@ -312,18 +315,63 @@ func (pkg *Package) check(fs *token.FileSet, astFiles []*ast.File) {
 }
 
 func (g *Generator) transformValueNames(values []Value, transformMethod string) {
-	var sep rune
+	var fn func(src string) string
 	switch transformMethod {
 	case "snake":
-		sep = '_'
+		fn = func(s string) string {
+			return strings.ToLower(name.Delimit(s, '_'))
+		}
+	case "snake_upper", "snake-upper":
+		fn = func(s string) string {
+			return strings.ToUpper(name.Delimit(s, '_'))
+		}
 	case "kebab":
-		sep = '-'
+		fn = func(s string) string {
+			return strings.ToLower(name.Delimit(s, '-'))
+		}
+	case "kebab_upper", "kebab-upper":
+		fn = func(s string) string {
+			return strings.ToUpper(name.Delimit(s, '-'))
+		}
+	case "upper":
+		fn = func(s string) string {
+			return strings.ToUpper(s)
+		}
+	case "lower":
+		fn = func(s string) string {
+			return strings.ToLower(s)
+		}
+	case "title":
+		fn = func(s string) string {
+			return strings.Title(s)
+		}
+	case "title-lower":
+		fn = func(s string) string {
+			title := []rune(strings.Title(s))
+			title[0] = unicode.ToLower(title[0])
+			return string(title)
+		}
+	case "first":
+		fn = func(s string) string {
+			r, _ := utf8.DecodeRuneInString(s)
+			return string(r)
+		}
+	case "first_upper", "first-upper":
+		fn = func(s string) string {
+			r, _ := utf8.DecodeRuneInString(s)
+			return strings.ToUpper(string(r))
+		}
+	case "first_lower", "first-lower":
+		fn = func(s string) string {
+			r, _ := utf8.DecodeRuneInString(s)
+			return strings.ToLower(string(r))
+		}
 	default:
 		return
 	}
 
 	for i := range values {
-		values[i].name = strings.ToLower(name.Delimit(values[i].name, sep))
+		values[i].name = fn(values[i].name)
 	}
 }
 
@@ -334,8 +382,16 @@ func (g *Generator) trimValueNames(values []Value, prefix string) {
 	}
 }
 
+// prefixValueNames adds a prefix to each name
+func (g *Generator) prefixValueNames(values []Value, prefix string) {
+	for i := range values {
+		values[i].name = prefix + values[i].name
+	}
+}
+
 // generate produces the String method for the named type.
-func (g *Generator) generate(typeName string, includeJSON, includeYAML, includeSQL, includeText bool, transformMethod string, trimPrefix string) {
+func (g *Generator) generate(typeName string, includeJSON, includeYAML, includeSQL, includeText bool,
+	transformMethod string, trimPrefix string, addPrefix string) {
 	values := make([]Value, 0, 100)
 	for _, file := range g.pkg.files {
 		// Set the state for this run of the walker.
@@ -355,6 +411,8 @@ func (g *Generator) generate(typeName string, includeJSON, includeYAML, includeS
 
 	g.transformValueNames(values, transformMethod)
 
+	g.prefixValueNames(values, addPrefix)
+
 	runs := splitIntoRuns(values)
 	// The decision of which pattern to use depends on the number of
 	// runs in the numbers. If there's only one, it's easy. For more than

testdata/transform.go

@@ -1,25 +0,0 @@
-package main
-
-import "fmt"
-
-type CamelCaseValue int
-
-const (
-	CamelCaseValueOne CamelCaseValue = iota
-	CamelCaseValueTwo
-	CamelCaseValueThree
-)
-
-func main() {
-	ck(CamelCaseValueOne, "camel_case_value_one")
-	ck(CamelCaseValueTwo, "camel_case_value_two")
-	ck(CamelCaseValueThree, "camel_case_value_three")
-	ck(-127, "CamelCaseValue(-127)")
-	ck(127, "CamelCaseValue(127)")
-}
-
-func ck(value CamelCaseValue, str string) {
-	if fmt.Sprint(value) != str {
-		panic("transform.go: " + str)
-	}
-}

testdata/transform_first.go

@@ -0,0 +1,25 @@
+package main
+
+import "fmt"
+
+type FirstCaseValue int
+
+const (
+	Male FirstCaseValue = iota
+	Female
+	unknown
+)
+
+func main() {
+	ck(Male, "M")
+	ck(Female, "F")
+	ck(unknown, "u")
+	ck(-127, "FirstCaseValue(-127)")
+	ck(127, "FirstCaseValue(127)")
+}
+
+func ck(value FirstCaseValue, str string) {
+	if fmt.Sprint(value) != str {
+		panic("transform_first.go: " + str)
+	}
+}

testdata/transform_first_lower.go

@@ -0,0 +1,25 @@
+package main
+
+import "fmt"
+
+type FirstLowerCaseValue int
+
+const (
+	Male FirstLowerCaseValue = iota
+	Female
+	Unknown
+)
+
+func main() {
+	ck(Male, "m")
+	ck(Female, "f")
+	ck(Unknown, "u")
+	ck(-127, "FirstLowerCaseValue(-127)")
+	ck(127, "FirstLowerCaseValue(127)")
+}
+
+func ck(value FirstLowerCaseValue, str string) {
+	if fmt.Sprint(value) != str {
+		panic("transform_first_lower.go: " + str)
+	}
+}

testdata/transform_first_upper.go

@@ -0,0 +1,25 @@
+package main
+
+import "fmt"
+
+type FirstUpperCaseValue int
+
+const (
+	male FirstUpperCaseValue = iota
+	female
+	unknown
+)
+
+func main() {
+	ck(male, "M")
+	ck(female, "F")
+	ck(unknown, "U")
+	ck(-127, "FirstUpperCaseValue(-127)")
+	ck(127, "FirstUpperCaseValue(127)")
+}
+
+func ck(value FirstUpperCaseValue, str string) {
+	if fmt.Sprint(value) != str {
+		panic("transform_first_upper.go: " + str)
+	}
+}

testdata/transform_kebab.go

@@ -0,0 +1,25 @@
+package main
+
+import "fmt"
+
+type KebabCaseValue int
+
+const (
+	KebabCaseValueOne KebabCaseValue = iota
+	KebabCaseValueTwo
+	KebabCaseValueThree
+)
+
+func main() {
+	ck(KebabCaseValueOne, "kebab-case-value-one")
+	ck(KebabCaseValueTwo, "kebab-case-value-two")
+	ck(KebabCaseValueThree, "kebab-case-value-three")
+	ck(-127, "KebabCaseValue(-127)")
+	ck(127, "KebabCaseValue(127)")
+}
+
+func ck(value KebabCaseValue, str string) {
+	if fmt.Sprint(value) != str {
+		panic("transform_kebab.go: " + str)
+	}
+}

testdata/transform_kebab_upper.go

@@ -0,0 +1,25 @@
+package main
+
+import "fmt"
+
+type KebabUpperCaseValue int
+
+const (
+	KebabUpperCaseValueOne KebabUpperCaseValue = iota
+	KebabUpperCaseValueTwo
+	KebabUpperCaseValueThree
+)
+
+func main() {
+	ck(KebabUpperCaseValueOne, "KEBAB-UPPER-CASE-VALUE-ONE")
+	ck(KebabUpperCaseValueTwo, "KEBAB-UPPER-CASE-VALUE-TWO")
+	ck(KebabUpperCaseValueThree, "KEBAB-UPPER-CASE-VALUE-THREE")
+	ck(-127, "KebabUpperCaseValue(-127)")
+	ck(127, "KebabUpperCaseValue(127)")
+}
+
+func ck(value KebabUpperCaseValue, str string) {
+	if fmt.Sprint(value) != str {
+		panic("transform_kebab_upper.go: " + str)
+	}
+}

testdata/transform_lower.go

@@ -0,0 +1,25 @@
+package main
+
+import "fmt"
+
+type LowerCaseValue int
+
+const (
+	LowerCaseValueOne LowerCaseValue = iota
+	LowerCaseValueTwo
+	LowerCaseValueThree
+)
+
+func main() {
+	ck(LowerCaseValueOne, "lowercasevalueone")
+	ck(LowerCaseValueTwo, "lowercasevaluetwo")
+	ck(LowerCaseValueThree, "lowercasevaluethree")
+	ck(-127, "LowerCaseValue(-127)")
+	ck(127, "LowerCaseValue(127)")
+}
+
+func ck(value LowerCaseValue, str string) {
+	if fmt.Sprint(value) != str {
+		panic("transform_lower.go: " + str)
+	}
+}

testdata/transform_snake.go

@@ -0,0 +1,25 @@
+package main
+
+import "fmt"
+
+type SnakeCaseValue int
+
+const (
+	SnakeCaseValueOne SnakeCaseValue = iota
+	SnakeCaseValueTwo
+	SnakeCaseValueThree
+)
+
+func main() {
+	ck(SnakeCaseValueOne, "snake_case_value_one")
+	ck(SnakeCaseValueTwo, "snake_case_value_two")
+	ck(SnakeCaseValueThree, "snake_case_value_three")
+	ck(-127, "SnakeCaseValue(-127)")
+	ck(127, "SnakeCaseValue(127)")
+}
+
+func ck(value SnakeCaseValue, str string) {
+	if fmt.Sprint(value) != str {
+		panic("transform_snake.go: " + str)
+	}
+}

testdata/transform_snake_upper.go

@@ -0,0 +1,25 @@
+package main
+
+import "fmt"
+
+type SnakeUpperCaseValue int
+
+const (
+	SnakeUpperCaseValueOne SnakeUpperCaseValue = iota
+	SnakeUpperCaseValueTwo
+	SnakeUpperCaseValueThree
+)
+
+func main() {
+	ck(SnakeUpperCaseValueOne, "SNAKE_UPPER_CASE_VALUE_ONE")
+	ck(SnakeUpperCaseValueTwo, "SNAKE_UPPER_CASE_VALUE_TWO")
+	ck(SnakeUpperCaseValueThree, "SNAKE_UPPER_CASE_VALUE_THREE")
+	ck(-127, "SnakeUpperCaseValue(-127)")
+	ck(127, "SnakeUpperCaseValue(127)")
+}
+
+func ck(value SnakeUpperCaseValue, str string) {
+	if fmt.Sprint(value) != str {
+		panic("transform_snake_upper.go: " + str)
+	}
+}

testdata/transform_title.go

@@ -0,0 +1,25 @@
+package main
+
+import "fmt"
+
+type TitleCaseValue int
+
+const (
+	titlecasevalueone TitleCaseValue = iota
+	titlecasevaluetwo
+	titlecasevaluethree
+)
+
+func main() {
+	ck(titlecasevalueone, "Titlecasevalueone")
+	ck(titlecasevaluetwo, "Titlecasevaluetwo")
+	ck(titlecasevaluethree, "Titlecasevaluethree")
+	ck(-127, "TitleCaseValue(-127)")
+	ck(127, "TitleCaseValue(127)")
+}
+
+func ck(value TitleCaseValue, str string) {
+	if fmt.Sprint(value) != str {
+		panic("transform_title.go: " + str)
+	}
+}

testdata/transform_upper.go

@@ -0,0 +1,25 @@
+package main
+
+import "fmt"
+
+type UpperCaseValue int
+
+const (
+	UpperCaseValueOne UpperCaseValue = iota
+	UpperCaseValueTwo
+	UpperCaseValueThree
+)
+
+func main() {
+	ck(UpperCaseValueOne, "UPPERCASEVALUEONE")
+	ck(UpperCaseValueTwo, "UPPERCASEVALUETWO")
+	ck(UpperCaseValueThree, "UPPERCASEVALUETHREE")
+	ck(-127, "UpperCaseValue(-127)")
+	ck(127, "UpperCaseValue(127)")
+}
+
+func ck(value UpperCaseValue, str string) {
+	if fmt.Sprint(value) != str {
+		panic("transform_upper.go: " + str)
+	}
+}