Option to add a ToString interface where numeric-based strings are generated

README.md

@@ -26,6 +26,8 @@ Flags:
         if true, json marshaling methods will be generated. Default: false
   -linecomment
         use line comment text as printed text when present
+  -tostring
+        if true, ToString function that returns an number-based string will be generated. Default: false
   -output string
         output file name; default srcdir/<type>_string.go
   -sql
@@ -71,6 +73,9 @@ When Enumer is applied to a type, it will generate:
   the enum conform to the `gopkg.in/yaml.v2.Marshaler` and `gopkg.in/yaml.v2.Unmarshaler` interfaces.
 - When the flag `sql` is provided, the methods for implementing the `Scanner` and `Valuer` interfaces.
   Useful when storing the enum in a database.
+- When the flag `tostring` is provided, the methods for implementing the `ToString` interfaces.
+  the `ToString` interface, Instead of an enumerated string, get a defined number-based string.
+
 
 
 For example, if we have an enum type called `Pill`,

golden_test.go

@@ -33,6 +33,15 @@ var golden = []Golden{
 	{"prime", primeIn},
 }
 
+var goldenToString = []Golden{
+	{"tostring_day", dayIn},
+	{"tostring_offset", offsetIn},
+	{"tostring_gap", gapIn},
+	{"tostring_num", numIn},
+	{"tostring_unum", unumIn},
+	{"tostring_prime", primeIn},
+}
+
 var goldenJSON = []Golden{
 	{"primeJson", primeJsonIn},
 }
@@ -315,45 +324,48 @@ const (
 
 func TestGolden(t *testing.T) {
 	for _, test := range golden {
-		runGoldenTest(t, test, false, false, false, false, false, false, true, "", "")
+		runGoldenTest(t, test, false, false, false, false, false, false, true, false, "", "")
+	}
+	for _, test := range goldenToString {
+		runGoldenTest(t, test, false, false, false, false, false, false, false, true, "", "")
 	}
 	for _, test := range goldenJSON {
-		runGoldenTest(t, test, true, false, false, false, false, false, false, "", "")
+		runGoldenTest(t, test, true, false, false, false, false, false, false, false, "", "")
 	}
 	for _, test := range goldenText {
-		runGoldenTest(t, test, false, false, false, true, false, false, false, "", "")
+		runGoldenTest(t, test, false, false, false, true, false, false, false, false, "", "")
 	}
 	for _, test := range goldenYAML {
-		runGoldenTest(t, test, false, true, false, false, false, false, false, "", "")
+		runGoldenTest(t, test, false, true, false, false, false, false, false, false, "", "")
 	}
 	for _, test := range goldenSQL {
-		runGoldenTest(t, test, false, false, true, false, false, false, false, "", "")
+		runGoldenTest(t, test, false, false, true, false, false, false, false, false, "", "")
 	}
 	for _, test := range goldenJSONAndSQL {
-		runGoldenTest(t, test, true, false, true, false, false, false, false, "", "")
+		runGoldenTest(t, test, true, false, true, false, false, false, false, false, "", "")
 	}
 	for _, test := range goldenGQLGen {
-		runGoldenTest(t, test, false, false, false, false, false, true, false, "", "")
+		runGoldenTest(t, test, false, false, false, false, false, true, false, false, "", "")
 	}
 	for _, test := range goldenTrimPrefix {
-		runGoldenTest(t, test, false, false, false, false, false, false, false, "Day", "")
+		runGoldenTest(t, test, false, false, false, false, false, false, false, false, "Day", "")
 	}
 	for _, test := range goldenTrimPrefixMultiple {
-		runGoldenTest(t, test, false, false, false, false, false, false, false, "Day,Night", "")
+		runGoldenTest(t, test, false, false, false, false, false, false, false, false, "Day,Night", "")
 	}
 	for _, test := range goldenWithPrefix {
-		runGoldenTest(t, test, false, false, false, false, false, false, false, "", "Day")
+		runGoldenTest(t, test, false, false, false, false, false, false, false, false, "", "Day")
 	}
 	for _, test := range goldenTrimAndAddPrefix {
-		runGoldenTest(t, test, false, false, false, false, false, false, false, "Day", "Night")
+		runGoldenTest(t, test, false, false, false, false, false, false, false, false, "Day", "Night")
 	}
 	for _, test := range goldenLinecomment {
-		runGoldenTest(t, test, false, false, false, false, true, false, false, "", "")
+		runGoldenTest(t, test, false, false, false, false, true, false, false, false, "", "")
 	}
 }
 
 func runGoldenTest(t *testing.T, test Golden,
-	generateJSON, generateYAML, generateSQL, generateText, linecomment, generateGQLGen, generateValuesMethod bool,
+	generateJSON, generateYAML, generateSQL, generateText, linecomment, generateGQLGen, generateValuesMethod, toString bool,
 	trimPrefix string, prefix string) {
 
 	var g Generator
@@ -382,7 +394,7 @@ func runGoldenTest(t *testing.T, test Golden,
 	if len(tokens) != 3 {
 		t.Fatalf("%s: need type declaration on first line", test.name)
 	}
-	g.generate(tokens[1], generateJSON, generateYAML, generateSQL, generateText, generateGQLGen, "noop", trimPrefix, prefix, linecomment, generateValuesMethod)
+	g.generate(tokens[1], generateJSON, generateYAML, generateSQL, generateText, generateGQLGen, "noop", trimPrefix, prefix, linecomment, generateValuesMethod, toString)
 	got := string(g.format())
 	if got != loadGolden(test.name) {
 		// Use this to help build a golden text when changes are needed

stringer.go

@@ -56,6 +56,7 @@ var (
 	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: \"\"")
 	linecomment     = flag.Bool("linecomment", false, "use line comment text as printed text when present")
+	tostring        = flag.Bool("tostring", false, "if true, ToString function that returns an number-based string will be generated. Default: false")
 )
 
 var comments arrayFlags
@@ -135,7 +136,7 @@ func main() {
 
 	// Run generate for each type.
 	for _, typeName := range typs {
-		g.generate(typeName, *json, *yaml, *sql, *text, *gqlgen, *transformMethod, *trimPrefix, *addPrefix, *linecomment, *altValuesFunc)
+		g.generate(typeName, *json, *yaml, *sql, *text, *gqlgen, *transformMethod, *trimPrefix, *addPrefix, *linecomment, *altValuesFunc, *tostring)
 	}
 
 	// Format the output.
@@ -415,7 +416,8 @@ func (g *Generator) prefixValueNames(values []Value, prefix string) {
 // generate produces the String method for the named type.
 func (g *Generator) generate(typeName string,
 	includeJSON, includeYAML, includeSQL, includeText, includeGQLGen bool,
-	transformMethod string, trimPrefix string, addPrefix string, lineComment bool, includeValuesMethod bool) {
+	transformMethod string, trimPrefix string, addPrefix string, lineComment bool, includeValuesMethod bool,
+	toString bool) {
 	values := make([]Value, 0, 100)
 	for _, file := range g.pkg.files {
 		file.lineComment = lineComment
@@ -465,6 +467,9 @@ func (g *Generator) generate(typeName string,
 	if includeValuesMethod {
 		g.buildAltStringValuesMethod(typeName)
 	}
+	if toString {
+		g.buildToStringMethod(typeName)
+	}
 
 	g.buildNoOpOrderChangeDetect(runs, typeName)
 
@@ -774,9 +779,10 @@ func (g *Generator) buildOneRun(runs [][]Value, typeName string) {
 }
 
 // Arguments to format are:
-// 	[1]: type name
-// 	[2]: size of index element (8 for uint8 etc.)
-// 	[3]: less than zero check (for signed types)
+//
+//	[1]: type name
+//	[2]: size of index element (8 for uint8 etc.)
+//	[3]: less than zero check (for signed types)
 const stringOneRun = `func (i %[1]s) String() string {
 	if %[3]si >= %[1]s(len(_%[1]sIndex)-1) {
 		return fmt.Sprintf("%[1]s(%%d)", i)
@@ -786,10 +792,11 @@ const stringOneRun = `func (i %[1]s) String() string {
 `
 
 // Arguments to format are:
-// 	[1]: type name
-// 	[2]: lowest defined value for type, as a string
-// 	[3]: size of index element (8 for uint8 etc.)
-// 	[4]: less than zero check (for signed types)
+//
+//	[1]: type name
+//	[2]: lowest defined value for type, as a string
+//	[3]: size of index element (8 for uint8 etc.)
+//	[4]: less than zero check (for signed types)
 const stringOneRunWithOffset = `func (i %[1]s) String() string {
 	i -= %[2]s
 	if %[4]si >= %[1]s(len(_%[1]sIndex)-1) {
@@ -868,3 +875,18 @@ const stringMap = `func (i %[1]s) String() string {
 	return fmt.Sprintf("%[1]s(%%d)", i)
 }
 `
+
+func (g *Generator) buildToStringMethod(typeName string) {
+	g.Printf(toStringFromInt, typeName)
+}
+
+// Arguments to format are:
+//
+//	[1]: type name
+//	[2]: size of index element (8 for uint8 etc.)
+//	[3]: less than zero check (for signed types)
+const toStringFromInt = `// ToString converts %[1]s to an int-based string and returns it.
+func (i %[1]s) ToString() string {
+	return strconv.Itoa(int(i))
+}
+`

testdata/tostring_day.golden

@@ -0,0 +1,95 @@
+
+const _DayName = "MondayTuesdayWednesdayThursdayFridaySaturdaySunday"
+
+var _DayIndex = [...]uint8{0, 6, 13, 22, 30, 36, 44, 50}
+
+const _DayLowerName = "mondaytuesdaywednesdaythursdayfridaysaturdaysunday"
+
+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]]
+}
+
+// ToString converts Day to an int-based string and returns it.
+func (i Day) ToString() string {
+	return strconv.Itoa(int(i))
+}
+
+// An "invalid array index" compiler error signifies that the constant values have changed.
+// Re-run the stringer command to generate them again.
+func _DayNoOp() {
+	var x [1]struct{}
+	_ = x[Monday-(0)]
+	_ = x[Tuesday-(1)]
+	_ = x[Wednesday-(2)]
+	_ = x[Thursday-(3)]
+	_ = x[Friday-(4)]
+	_ = x[Saturday-(5)]
+	_ = x[Sunday-(6)]
+}
+
+var _DayValues = []Day{Monday, Tuesday, Wednesday, Thursday, Friday, Saturday, Sunday}
+
+var _DayNameToValueMap = map[string]Day{
+	_DayName[0:6]:        Monday,
+	_DayLowerName[0:6]:   Monday,
+	_DayName[6:13]:       Tuesday,
+	_DayLowerName[6:13]:  Tuesday,
+	_DayName[13:22]:      Wednesday,
+	_DayLowerName[13:22]: Wednesday,
+	_DayName[22:30]:      Thursday,
+	_DayLowerName[22:30]: Thursday,
+	_DayName[30:36]:      Friday,
+	_DayLowerName[30:36]: Friday,
+	_DayName[36:44]:      Saturday,
+	_DayLowerName[36:44]: Saturday,
+	_DayName[44:50]:      Sunday,
+	_DayLowerName[44:50]: Sunday,
+}
+
+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) {
+	if val, ok := _DayNameToValueMap[s]; ok {
+		return val, nil
+	}
+
+	if val, ok := _DayNameToValueMap[strings.ToLower(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
+}

testdata/tostring_gap.golden

@@ -0,0 +1,116 @@
+
+const (
+	_GapName_0      = "TwoThree"
+	_GapLowerName_0 = "twothree"
+	_GapName_1      = "FiveSixSevenEightNine"
+	_GapLowerName_1 = "fivesixseveneightnine"
+	_GapName_2      = "Eleven"
+	_GapLowerName_2 = "eleven"
+)
+
+var (
+	_GapIndex_0 = [...]uint8{0, 3, 8}
+	_GapIndex_1 = [...]uint8{0, 4, 7, 12, 17, 21}
+	_GapIndex_2 = [...]uint8{0, 6}
+)
+
+func (i Gap) String() string {
+	switch {
+	case 2 <= i && i <= 3:
+		i -= 2
+		return _GapName_0[_GapIndex_0[i]:_GapIndex_0[i+1]]
+	case 5 <= i && i <= 9:
+		i -= 5
+		return _GapName_1[_GapIndex_1[i]:_GapIndex_1[i+1]]
+	case i == 11:
+		return _GapName_2
+	default:
+		return fmt.Sprintf("Gap(%d)", i)
+	}
+}
+
+// ToString converts Gap to an int-based string and returns it.
+func (i Gap) ToString() string {
+	return strconv.Itoa(int(i))
+}
+
+// An "invalid array index" compiler error signifies that the constant values have changed.
+// Re-run the stringer command to generate them again.
+func _GapNoOp() {
+	var x [1]struct{}
+	_ = x[Two-(2)]
+	_ = x[Three-(3)]
+	_ = x[Five-(5)]
+	_ = x[Six-(6)]
+	_ = x[Seven-(7)]
+	_ = x[Eight-(8)]
+	_ = x[Nine-(9)]
+	_ = x[Eleven-(11)]
+}
+
+var _GapValues = []Gap{Two, Three, Five, Six, Seven, Eight, Nine, Eleven}
+
+var _GapNameToValueMap = map[string]Gap{
+	_GapName_0[0:3]:        Two,
+	_GapLowerName_0[0:3]:   Two,
+	_GapName_0[3:8]:        Three,
+	_GapLowerName_0[3:8]:   Three,
+	_GapName_1[0:4]:        Five,
+	_GapLowerName_1[0:4]:   Five,
+	_GapName_1[4:7]:        Six,
+	_GapLowerName_1[4:7]:   Six,
+	_GapName_1[7:12]:       Seven,
+	_GapLowerName_1[7:12]:  Seven,
+	_GapName_1[12:17]:      Eight,
+	_GapLowerName_1[12:17]: Eight,
+	_GapName_1[17:21]:      Nine,
+	_GapLowerName_1[17:21]: Nine,
+	_GapName_2[0:6]:        Eleven,
+	_GapLowerName_2[0:6]:   Eleven,
+}
+
+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) {
+	if val, ok := _GapNameToValueMap[s]; ok {
+		return val, nil
+	}
+
+	if val, ok := _GapNameToValueMap[strings.ToLower(s)]; ok {
+		return val, nil
+	}
+	return 0, fmt.Errorf("%s does not belong to Gap values", s)
+}
+
+// GapValues returns all values of the enum
+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 {
+		if i == v {
+			return true
+		}
+	}
+	return false
+}

testdata/tostring_num.golden

@@ -0,0 +1,88 @@
+
+const _NumName = "m_2m_1m0m1m2"
+
+var _NumIndex = [...]uint8{0, 3, 6, 8, 10, 12}
+
+const _NumLowerName = "m_2m_1m0m1m2"
+
+func (i Num) String() string {
+	i -= -2
+	if i < 0 || i >= Num(len(_NumIndex)-1) {
+		return fmt.Sprintf("Num(%d)", i+-2)
+	}
+	return _NumName[_NumIndex[i]:_NumIndex[i+1]]
+}
+
+// ToString converts Num to an int-based string and returns it.
+func (i Num) ToString() string {
+	return strconv.Itoa(int(i))
+}
+
+// An "invalid array index" compiler error signifies that the constant values have changed.
+// Re-run the stringer command to generate them again.
+func _NumNoOp() {
+	var x [1]struct{}
+	_ = x[m_2-(-2)]
+	_ = x[m_1-(-1)]
+	_ = x[m0-(0)]
+	_ = x[m1-(1)]
+	_ = x[m2-(2)]
+}
+
+var _NumValues = []Num{m_2, m_1, m0, m1, m2}
+
+var _NumNameToValueMap = map[string]Num{
+	_NumName[0:3]:        m_2,
+	_NumLowerName[0:3]:   m_2,
+	_NumName[3:6]:        m_1,
+	_NumLowerName[3:6]:   m_1,
+	_NumName[6:8]:        m0,
+	_NumLowerName[6:8]:   m0,
+	_NumName[8:10]:       m1,
+	_NumLowerName[8:10]:  m1,
+	_NumName[10:12]:      m2,
+	_NumLowerName[10:12]: m2,
+}
+
+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) {
+	if val, ok := _NumNameToValueMap[s]; ok {
+		return val, nil
+	}
+
+	if val, ok := _NumNameToValueMap[strings.ToLower(s)]; ok {
+		return val, nil
+	}
+	return 0, fmt.Errorf("%s does not belong to Num values", s)
+}
+
+// NumValues returns all values of the enum
+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 {
+		if i == v {
+			return true
+		}
+	}
+	return false
+}

testdata/tostring_offset.golden

@@ -0,0 +1,80 @@
+
+const _NumberName = "OneTwoThree"
+
+var _NumberIndex = [...]uint8{0, 3, 6, 11}
+
+const _NumberLowerName = "onetwothree"
+
+func (i Number) String() string {
+	i -= 1
+	if i < 0 || i >= Number(len(_NumberIndex)-1) {
+		return fmt.Sprintf("Number(%d)", i+1)
+	}
+	return _NumberName[_NumberIndex[i]:_NumberIndex[i+1]]
+}
+
+// ToString converts Number to an int-based string and returns it.
+func (i Number) ToString() string {
+	return strconv.Itoa(int(i))
+}
+
+// An "invalid array index" compiler error signifies that the constant values have changed.
+// Re-run the stringer command to generate them again.
+func _NumberNoOp() {
+	var x [1]struct{}
+	_ = x[One-(1)]
+	_ = x[Two-(2)]
+	_ = x[Three-(3)]
+}
+
+var _NumberValues = []Number{One, Two, Three}
+
+var _NumberNameToValueMap = map[string]Number{
+	_NumberName[0:3]:       One,
+	_NumberLowerName[0:3]:  One,
+	_NumberName[3:6]:       Two,
+	_NumberLowerName[3:6]:  Two,
+	_NumberName[6:11]:      Three,
+	_NumberLowerName[6:11]: Three,
+}
+
+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) {
+	if val, ok := _NumberNameToValueMap[s]; ok {
+		return val, nil
+	}
+
+	if val, ok := _NumberNameToValueMap[strings.ToLower(s)]; ok {
+		return val, nil
+	}
+	return 0, fmt.Errorf("%s does not belong to Number values", s)
+}
+
+// NumberValues returns all values of the enum
+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 {
+		if i == v {
+			return true
+		}
+	}
+	return false
+}

testdata/tostring_prime.golden

@@ -0,0 +1,128 @@
+
+const _PrimeName = "p2p3p5p7p11p13p17p19p23p29p37p41p43"
+const _PrimeLowerName = "p2p3p5p7p11p13p17p19p23p29p37p41p43"
+
+var _PrimeMap = map[Prime]string{
+	2:  _PrimeName[0:2],
+	3:  _PrimeName[2:4],
+	5:  _PrimeName[4:6],
+	7:  _PrimeName[6:8],
+	11: _PrimeName[8:11],
+	13: _PrimeName[11:14],
+	17: _PrimeName[14:17],
+	19: _PrimeName[17:20],
+	23: _PrimeName[20:23],
+	29: _PrimeName[23:26],
+	31: _PrimeName[26:29],
+	41: _PrimeName[29:32],
+	43: _PrimeName[32:35],
+}
+
+func (i Prime) String() string {
+	if str, ok := _PrimeMap[i]; ok {
+		return str
+	}
+	return fmt.Sprintf("Prime(%d)", i)
+}
+
+// ToString converts Prime to an int-based string and returns it.
+func (i Prime) ToString() string {
+	return strconv.Itoa(int(i))
+}
+
+// An "invalid array index" compiler error signifies that the constant values have changed.
+// Re-run the stringer command to generate them again.
+func _PrimeNoOp() {
+	var x [1]struct{}
+	_ = x[p2-(2)]
+	_ = x[p3-(3)]
+	_ = x[p5-(5)]
+	_ = x[p7-(7)]
+	_ = x[p11-(11)]
+	_ = x[p13-(13)]
+	_ = x[p17-(17)]
+	_ = x[p19-(19)]
+	_ = x[p23-(23)]
+	_ = x[p29-(29)]
+	_ = x[p37-(31)]
+	_ = x[p41-(41)]
+	_ = x[p43-(43)]
+}
+
+var _PrimeValues = []Prime{p2, p3, p5, p7, p11, p13, p17, p19, p23, p29, p37, p41, p43}
+
+var _PrimeNameToValueMap = map[string]Prime{
+	_PrimeName[0:2]:        p2,
+	_PrimeLowerName[0:2]:   p2,
+	_PrimeName[2:4]:        p3,
+	_PrimeLowerName[2:4]:   p3,
+	_PrimeName[4:6]:        p5,
+	_PrimeLowerName[4:6]:   p5,
+	_PrimeName[6:8]:        p7,
+	_PrimeLowerName[6:8]:   p7,
+	_PrimeName[8:11]:       p11,
+	_PrimeLowerName[8:11]:  p11,
+	_PrimeName[11:14]:      p13,
+	_PrimeLowerName[11:14]: p13,
+	_PrimeName[14:17]:      p17,
+	_PrimeLowerName[14:17]: p17,
+	_PrimeName[17:20]:      p19,
+	_PrimeLowerName[17:20]: p19,
+	_PrimeName[20:23]:      p23,
+	_PrimeLowerName[20:23]: p23,
+	_PrimeName[23:26]:      p29,
+	_PrimeLowerName[23:26]: p29,
+	_PrimeName[26:29]:      p37,
+	_PrimeLowerName[26:29]: p37,
+	_PrimeName[29:32]:      p41,
+	_PrimeLowerName[29:32]: p41,
+	_PrimeName[32:35]:      p43,
+	_PrimeLowerName[32:35]: p43,
+}
+
+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) {
+	if val, ok := _PrimeNameToValueMap[s]; ok {
+		return val, nil
+	}
+
+	if val, ok := _PrimeNameToValueMap[strings.ToLower(s)]; ok {
+		return val, nil
+	}
+	return 0, fmt.Errorf("%s does not belong to Prime values", s)
+}
+
+// PrimeValues returns all values of the enum
+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]
+	return ok
+}

testdata/tostring_unum.golden

@@ -0,0 +1,98 @@
+
+const (
+	_UnumName_0      = "m0m1m2"
+	_UnumLowerName_0 = "m0m1m2"
+	_UnumName_1      = "m_2m_1"
+	_UnumLowerName_1 = "m_2m_1"
+)
+
+var (
+	_UnumIndex_0 = [...]uint8{0, 2, 4, 6}
+	_UnumIndex_1 = [...]uint8{0, 3, 6}
+)
+
+func (i Unum) String() string {
+	switch {
+	case 0 <= i && i <= 2:
+		return _UnumName_0[_UnumIndex_0[i]:_UnumIndex_0[i+1]]
+	case 253 <= i && i <= 254:
+		i -= 253
+		return _UnumName_1[_UnumIndex_1[i]:_UnumIndex_1[i+1]]
+	default:
+		return fmt.Sprintf("Unum(%d)", i)
+	}
+}
+
+// ToString converts Unum to an int-based string and returns it.
+func (i Unum) ToString() string {
+	return strconv.Itoa(int(i))
+}
+
+// An "invalid array index" compiler error signifies that the constant values have changed.
+// Re-run the stringer command to generate them again.
+func _UnumNoOp() {
+	var x [1]struct{}
+	_ = x[m0-(0)]
+	_ = x[m1-(1)]
+	_ = x[m2-(2)]
+	_ = x[m_2-(253)]
+	_ = x[m_1-(254)]
+}
+
+var _UnumValues = []Unum{m0, m1, m2, m_2, m_1}
+
+var _UnumNameToValueMap = map[string]Unum{
+	_UnumName_0[0:2]:      m0,
+	_UnumLowerName_0[0:2]: m0,
+	_UnumName_0[2:4]:      m1,
+	_UnumLowerName_0[2:4]: m1,
+	_UnumName_0[4:6]:      m2,
+	_UnumLowerName_0[4:6]: m2,
+	_UnumName_1[0:3]:      m_2,
+	_UnumLowerName_1[0:3]: m_2,
+	_UnumName_1[3:6]:      m_1,
+	_UnumLowerName_1[3:6]: m_1,
+}
+
+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) {
+	if val, ok := _UnumNameToValueMap[s]; ok {
+		return val, nil
+	}
+
+	if val, ok := _UnumNameToValueMap[strings.ToLower(s)]; ok {
+		return val, nil
+	}
+	return 0, fmt.Errorf("%s does not belong to Unum values", s)
+}
+
+// UnumValues returns all values of the enum
+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 {
+		if i == v {
+			return true
+		}
+	}
+	return false
+}