Empty string if out of range

enumer.go

@@ -3,6 +3,7 @@ package main
 import "fmt"
 
 // Arguments to format are:
+//
 //	[1]: type name
 const stringNameToValueMethod = `// %[1]sString retrieves an enum value from the enum constants string name.
 // Throws an error if the param is not part of the enum.
@@ -19,6 +20,7 @@ func %[1]sString(s string) (%[1]s, error) {
 `
 
 // Arguments to format are:
+//
 //	[1]: type name
 const stringValuesMethod = `// %[1]sValues returns all values of the enum
 func %[1]sValues() []%[1]s {
@@ -27,6 +29,7 @@ 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 {
@@ -37,6 +40,7 @@ func %[1]sStrings() []string {
 `
 
 // 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
 func (i %[1]s) IsA%[1]s() bool {
@@ -50,6 +54,7 @@ func (i %[1]s) IsA%[1]s() bool {
 `
 
 // Arguments to format are:
+//
 //	[1]: type name
 const stringBelongsMethodSet = `// IsA%[1]s returns "true" if the value is listed in the enum definition. "false" otherwise
 func (i %[1]s) IsA%[1]s() bool {
@@ -59,6 +64,7 @@ func (i %[1]s) IsA%[1]s() bool {
 `
 
 // Arguments to format are:
+//
 //	[1]: type name
 const altStringValuesMethod = `func (%[1]s) Values() []string {
 	return %[1]sStrings()
@@ -144,6 +150,7 @@ func (g *Generator) printNamesSlice(runs [][]Value, typeName string, runsThresho
 }
 
 // Arguments to format are:
+//
 //	[1]: type name
 const jsonMethods = `
 // MarshalJSON implements the json.Marshaler interface for %[1]s
@@ -169,6 +176,7 @@ func (g *Generator) buildJSONMethods(runs [][]Value, typeName string, runsThresh
 }
 
 // Arguments to format are:
+//
 //	[1]: type name
 const textMethods = `
 // MarshalText implements the encoding.TextMarshaler interface for %[1]s
@@ -189,11 +197,12 @@ func (g *Generator) buildTextMethods(runs [][]Value, typeName string, runsThresh
 }
 
 // Arguments to format are:
+//
 //	[1]: type name
 const yamlMethods = `
 // MarshalYAML implements a YAML Marshaler for %[1]s
 func (i %[1]s) MarshalYAML() (interface{}, error) {
-	return i.String(), nil
+	return i.string()
 }
 
 // UnmarshalYAML implements a YAML Unmarshaler for %[1]s

sql.go

@@ -1,9 +1,10 @@
 package main
 
 // Arguments to format are:
+//
 //	[1]: type name
 const valueMethod = `func (i %[1]s) Value() (driver.Value, error) {
-	return i.String(), nil
+	return i.string()
 }
 `
 

stringer.go

@@ -774,28 +774,40 @@ 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)
-const stringOneRun = `func (i %[1]s) String() string {
+//
+//	[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, error) {
 	if %[3]si >= %[1]s(len(_%[1]sIndex)-1) {
-		return fmt.Sprintf("%[1]s(%%d)", i)
+		return "", fmt.Errorf("value is out of enum range")
 	}
-	return _%[1]sName[_%[1]sIndex[i]:_%[1]sIndex[i+1]]
+	return _%[1]sName[_%[1]sIndex[i]:_%[1]sIndex[i+1]], nil
+}
+
+func (i %[1]s) String() string {
+	val, _ := i.string()
+	return val
 }
 `
 
 // 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)
-const stringOneRunWithOffset = `func (i %[1]s) String() string {
+//
+//	[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, error) {
 	i -= %[2]s
 	if %[4]si >= %[1]s(len(_%[1]sIndex)-1) {
-		return fmt.Sprintf("%[1]s(%%d)", i + %[2]s)
+		return "", fmt.Errorf("value is out of enum range")
 	}
-	return _%[1]sName[_%[1]sIndex[i] : _%[1]sIndex[i+1]]
+	return _%[1]sName[_%[1]sIndex[i] : _%[1]sIndex[i+1]], nil
+}
+
+func (i %[1]s) String() string {
+	val, _ := i.string()
+	return val
 }
 `
 
@@ -820,7 +832,7 @@ func (g *Generator) buildMultipleRuns(runs [][]Value, typeName string) {
 			typeName, i, typeName, i, typeName, i)
 	}
 	g.Printf("\tdefault:\n")
-	g.Printf("\t\treturn fmt.Sprintf(\"%s(%%d)\", i)\n", typeName)
+	g.Printf("\t\treturn \"\"\n")
 	g.Printf("\t}\n")
 	g.Printf("}\n")
 }
@@ -861,10 +873,15 @@ func (g *Generator) buildNoOpOrderChangeDetect(runs [][]Value, typeName string)
 }
 
 // Argument to format is the type name.
-const stringMap = `func (i %[1]s) String() string {
+const stringMap = `func (i %[1]s) string() (string, error) {
 	if str, ok := _%[1]sMap[i]; ok {
-		return str
+		return str, nil
 	}
-	return fmt.Sprintf("%[1]s(%%d)", i)
+	return "", fmt.Errorf("value is out of enum range") 
+}
+
+func (i %[1]s) String() string {
+	str, _ := i.string()
+	return str
 }
 `

testdata/day.go

@@ -28,8 +28,8 @@ func main() {
 	ck(Friday, "Friday")
 	ck(Saturday, "Saturday")
 	ck(Sunday, "Sunday")
-	ck(-127, "Day(-127)")
-	ck(127, "Day(127)")
+	ck(-127, "")
+	ck(127, "")
 	ckDayString(Sunday, "Sunday")
 	ckDayString(Sunday, "sunday")
 

testdata/day.golden

@@ -5,11 +5,16 @@ var _DayIndex = [...]uint8{0, 6, 13, 22, 30, 36, 44, 50}
 
 const _DayLowerName = "mondaytuesdaywednesdaythursdayfridaysaturdaysunday"
 
-func (i Day) String() string {
+func (i Day) string() (string, error) {
 	if i < 0 || i >= Day(len(_DayIndex)-1) {
-		return fmt.Sprintf("Day(%d)", i)
+		return "", fmt.Errorf("value is out of enum range")
 	}
-	return _DayName[_DayIndex[i]:_DayIndex[i+1]]
+	return _DayName[_DayIndex[i]:_DayIndex[i+1]], nil
+}
+
+func (i Day) String() string {
+	val, _ := i.string()
+	return val
 }
 
 func (Day) Values() []string {

testdata/dayTrimAndPrefix.golden

@@ -5,11 +5,16 @@ var _DayIndex = [...]uint8{0, 11, 23, 37, 50, 61, 74, 85}
 
 const _DayLowerName = "nightmondaynighttuesdaynightwednesdaynightthursdaynightfridaynightsaturdaynightsunday"
 
-func (i Day) String() string {
+func (i Day) string() (string, error) {
 	if i < 0 || i >= Day(len(_DayIndex)-1) {
-		return fmt.Sprintf("Day(%d)", i)
+		return "", fmt.Errorf("value is out of enum range")
 	}
-	return _DayName[_DayIndex[i]:_DayIndex[i+1]]
+	return _DayName[_DayIndex[i]:_DayIndex[i+1]], nil
+}
+
+func (i Day) String() string {
+	val, _ := i.string()
+	return val
 }
 
 // An "invalid array index" compiler error signifies that the constant values have changed.

testdata/dayWithLinecomment.golden

@@ -5,11 +5,16 @@ var _DayIndex = [...]uint8{0, 5, 12, 21, 29, 36, 44, 50}
 
 const _DayLowerName = "lunestuesdaywednesdaythursdayviernessaturdaysunday"
 
-func (i Day) String() string {
+func (i Day) string() (string, error) {
 	if i < 0 || i >= Day(len(_DayIndex)-1) {
-		return fmt.Sprintf("Day(%d)", i)
+		return "", fmt.Errorf("value is out of enum range")
 	}
-	return _DayName[_DayIndex[i]:_DayIndex[i+1]]
+	return _DayName[_DayIndex[i]:_DayIndex[i+1]], nil
+}
+
+func (i Day) String() string {
+	val, _ := i.string()
+	return val
 }
 
 // An "invalid array index" compiler error signifies that the constant values have changed.

testdata/dayWithPrefix.golden

@@ -5,11 +5,16 @@ var _DayIndex = [...]uint8{0, 9, 19, 31, 42, 51, 62, 71}
 
 const _DayLowerName = "daymondaydaytuesdaydaywednesdaydaythursdaydayfridaydaysaturdaydaysunday"
 
-func (i Day) String() string {
+func (i Day) string() (string, error) {
 	if i < 0 || i >= Day(len(_DayIndex)-1) {
-		return fmt.Sprintf("Day(%d)", i)
+		return "", fmt.Errorf("value is out of enum range")
 	}
-	return _DayName[_DayIndex[i]:_DayIndex[i+1]]
+	return _DayName[_DayIndex[i]:_DayIndex[i+1]], nil
+}
+
+func (i Day) String() string {
+	val, _ := i.string()
+	return val
 }
 
 // An "invalid array index" compiler error signifies that the constant values have changed.

testdata/gap.go

@@ -22,19 +22,19 @@ const (
 )
 
 func main() {
-	ck(0, "Gap(0)")
-	ck(1, "Gap(1)")
+	ck(0, "")
+	ck(1, "")
 	ck(Two, "Two")
 	ck(Three, "Three")
-	ck(4, "Gap(4)")
+	ck(4, "")
 	ck(Five, "Five")
 	ck(Six, "Six")
 	ck(Seven, "Seven")
 	ck(Eight, "Eight")
 	ck(Nine, "Nine")
-	ck(10, "Gap(10)")
+	ck(10, "")
 	ck(Eleven, "Eleven")
-	ck(12, "Gap(12)")
+	ck(12, "")
 }
 
 func ck(gap Gap, str string) {

testdata/gap.golden

@@ -25,7 +25,7 @@ func (i Gap) String() string {
 	case i == 11:
 		return _GapName_2
 	default:
-		return fmt.Sprintf("Gap(%d)", i)
+		return ""
 	}
 }
 

testdata/num.go

@@ -19,13 +19,13 @@ const (
 )
 
 func main() {
-	ck(-3, "Num(-3)")
+	ck(-3, "")
 	ck(m_2, "m_2")
 	ck(m_1, "m_1")
 	ck(m0, "m0")
 	ck(m1, "m1")
 	ck(m2, "m2")
-	ck(3, "Num(3)")
+	ck(3, "")
 }
 
 func ck(num Num, str string) {

testdata/num.golden

@@ -5,12 +5,17 @@ var _NumIndex = [...]uint8{0, 3, 6, 8, 10, 12}
 
 const _NumLowerName = "m_2m_1m0m1m2"
 
-func (i Num) String() string {
+func (i Num) string() (string, error) {
 	i -= -2
 	if i < 0 || i >= Num(len(_NumIndex)-1) {
-		return fmt.Sprintf("Num(%d)", i+-2)
+		return "", fmt.Errorf("value is out of enum range")
 	}
-	return _NumName[_NumIndex[i]:_NumIndex[i+1]]
+	return _NumName[_NumIndex[i]:_NumIndex[i+1]], nil
+}
+
+func (i Num) String() string {
+	val, _ := i.string()
+	return val
 }
 
 func (Num) Values() []string {

testdata/number.go

@@ -24,7 +24,7 @@ func main() {
 	ck(Two, "Two")
 	ck(Three, "Three")
 	ck(AnotherOne, "One")
-	ck(127, "Number(127)")
+	ck(127, "")
 }
 
 func ck(num Number, str string) {

testdata/offset.golden

@@ -5,12 +5,17 @@ var _NumberIndex = [...]uint8{0, 3, 6, 11}
 
 const _NumberLowerName = "onetwothree"
 
-func (i Number) String() string {
+func (i Number) string() (string, error) {
 	i -= 1
 	if i < 0 || i >= Number(len(_NumberIndex)-1) {
-		return fmt.Sprintf("Number(%d)", i+1)
+		return "", fmt.Errorf("value is out of enum range")
 	}
-	return _NumberName[_NumberIndex[i]:_NumberIndex[i+1]]
+	return _NumberName[_NumberIndex[i]:_NumberIndex[i+1]], nil
+}
+
+func (i Number) String() string {
+	val, _ := i.string()
+	return val
 }
 
 func (Number) Values() []string {

testdata/prime.go

@@ -29,11 +29,11 @@ const (
 )
 
 func main() {
-	ck(0, "Prime(0)")
-	ck(1, "Prime(1)")
+	ck(0, "")
+	ck(1, "")
 	ck(p2, "p2")
 	ck(p3, "p3")
-	ck(4, "Prime(4)")
+	ck(4, "")
 	ck(p5, "p5")
 	ck(p7, "p7")
 	ck(p77, "p7")
@@ -46,7 +46,7 @@ func main() {
 	ck(p37, "p37")
 	ck(p41, "p41")
 	ck(p43, "p43")
-	ck(44, "Prime(44)")
+	ck(44, "")
 }
 
 func ck(prime Prime, str string) {