Add support for -linecomment

golden_test.go

@@ -34,28 +34,32 @@ var golden = []Golden{
 }
 
 var goldenJSON = []Golden{
-	{"prime", primeJsonIn, primeJsonOut},
+	{"prime with JSON", primeJsonIn, primeJsonOut},
 }
 var goldenText = []Golden{
-	{"prime", primeTextIn, primeTextOut},
+	{"prime with Text", primeTextIn, primeTextOut},
 }
 
 var goldenYAML = []Golden{
-	{"prime", primeYamlIn, primeYamlOut},
+	{"prime with YAML", primeYamlIn, primeYamlOut},
 }
 
 var goldenSQL = []Golden{
-	{"prime", primeSqlIn, primeSqlOut},
+	{"prime with SQL", primeSqlIn, primeSqlOut},
 }
 
 var goldenJSONAndSQL = []Golden{
-	{"prime", primeJsonAndSqlIn, primeJsonAndSqlOut},
+	{"prime with JSONAndSQL", primeJsonAndSqlIn, primeJsonAndSqlOut},
 }
 
 var goldenPrefix = []Golden{
 	{"prefix", prefixIn, dayOut},
 }
 
+var goldenWithLineComments = []Golden{
+	{"primer with line Comments", primeWithLineCommentIn, primeWithLineCommentOut},
+}
+
 // Each example starts with "type XXX [u]int", with a single space separating them.
 
 // Simple test: enumeration of type int starting at 0.
@@ -1025,6 +1029,90 @@ const (
 )
 `
 
+const primeWithLineCommentIn = `type Prime int
+const (
+	p2 Prime = 2
+	p3 Prime = 3
+	p5 Prime = 5
+	p7 Prime = 7
+	p77 Prime = 7 // Duplicate; note that p77 doesn't appear below.
+	p11 Prime = 11
+	p13 Prime = 13
+	p17 Prime = 17
+	p19 Prime = 19
+	p23 Prime = 23
+	p29 Prime = 29
+	p37 Prime = 31
+	p41 Prime = 41
+	p43 Prime = 43
+)
+`
+
+const primeWithLineCommentOut = `
+const _PrimeName = "p2p3GoodPrimep7p11p13p17p19p23p29p37TwinPrime41Twin prime 43"
+
+var _PrimeMap = map[Prime]string{
+	2:  _PrimeName[0:2],
+	3:  _PrimeName[2:4],
+	5:  _PrimeName[4:13],
+	7:  _PrimeName[13:15],
+	11: _PrimeName[15:18],
+	13: _PrimeName[18:21],
+	17: _PrimeName[21:24],
+	19: _PrimeName[24:27],
+	23: _PrimeName[27:30],
+	29: _PrimeName[30:33],
+	31: _PrimeName[33:36],
+	41: _PrimeName[36:47],
+	43: _PrimeName[47:60],
+}
+
+func (i Prime) String() string {
+	if str, ok := _PrimeMap[i]; ok {
+		return str
+	}
+	return fmt.Sprintf("Prime(%d)", i)
+}
+
+var _PrimeValues = []Prime{2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 41, 43}
+
+var _PrimeNameToValueMap = map[string]Prime{
+	_PrimeName[0:2]:   2,
+	_PrimeName[2:4]:   3,
+	_PrimeName[4:13]:  5,
+	_PrimeName[13:15]: 7,
+	_PrimeName[15:18]: 11,
+	_PrimeName[18:21]: 13,
+	_PrimeName[21:24]: 17,
+	_PrimeName[24:27]: 19,
+	_PrimeName[27:30]: 23,
+	_PrimeName[30:33]: 29,
+	_PrimeName[33:36]: 31,
+	_PrimeName[36:47]: 41,
+	_PrimeName[47:60]: 43,
+}
+
+// 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
+	}
+	return 0, fmt.Errorf("%s does not belong to Prime values", s)
+}
+
+// PrimeValues returns all values of the enum
+func PrimeValues() []Prime {
+	return _PrimeValues
+}
+
+// IsAPrime returns "true" if the value is listed in the enum definition. "false" otherwise
+func (i Prime) IsAPrime() bool {
+	_, ok := _PrimeMap[i]
+	return ok
+}
+`
+
 func TestGolden(t *testing.T) {
 	for _, test := range golden {
 		runGoldenTest(t, test, false, false, false, false, "")
@@ -1076,7 +1164,7 @@ 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", prefix, false)
 	got := string(g.format())
 	if got != test.output {
 		t.Errorf("%s: got\n====\n%s====\nexpected\n====%s", test.name, got, test.output)

stringer.go

@@ -51,6 +51,7 @@ 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: \"\"")
+	lineComment     = flag.Bool("linecomment", false, "use line comment text as printed text when present")
 )
 
 var comments arrayFlags
@@ -120,7 +121,7 @@ func main() {
 
 	// Run generate for each type.
 	for _, typeName := range types {
-		g.generate(typeName, *json, *yaml, *sql, *text, *transformMethod, *trimPrefix)
+		g.generate(typeName, *json, *yaml, *sql, *text, *transformMethod, *trimPrefix, *lineComment)
 	}
 
 	// Format the output.
@@ -331,8 +332,16 @@ func (g *Generator) trimValueNames(values []Value, prefix string) {
 	}
 }
 
+func (g *Generator) replaceValuesWithLineComment(values []Value) {
+	for i, val := range values {
+		if val.comment != "" {
+			values[i].name = val.comment
+		}
+	}
+}
+
 // 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, lineComment bool) {
 	values := make([]Value, 0, 100)
 	for _, file := range g.pkg.files {
 		// Set the state for this run of the walker.
@@ -352,6 +361,10 @@ func (g *Generator) generate(typeName string, includeJSON, includeYAML, includeS
 
 	g.transformValueNames(values, transformMethod)
 
+	if lineComment {
+		g.replaceValuesWithLineComment(values)
+	}
+
 	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
@@ -446,6 +459,7 @@ type Value struct {
 	value   uint64 // Will be converted to int64 when needed.
 	signed  bool   // Whether the constant is a signed type.
 	str     string // The string representation given by the "go/exact" package.
+	comment string // The comment on the right of the constant
 }
 
 func (v *Value) String() string {
@@ -530,11 +544,17 @@ func (f *File) genDecl(node ast.Node) bool {
 			if !isInt {
 				u64 = uint64(i64)
 			}
+			comment := ""
+			if c := vspec.Comment; c != nil && len(c.List) == 1 {
+				comment = strings.TrimSpace(c.Text())
+			}
+
 			v := Value{
 				name:    name.Name,
 				value:   u64,
 				signed:  info&types.IsUnsigned == 0,
 				str:     value.String(),
+				comment: comment,
 			}
 			f.values = append(f.values, v)
 		}

util_test.go

@@ -54,7 +54,7 @@ Outer:
 	for n, test := range splitTests {
 		values := make([]Value, len(test.input))
 		for i, v := range test.input {
-			values[i] = Value{"", v, test.signed, fmt.Sprint(v)}
+			values[i] = Value{"", v, test.signed, fmt.Sprint(v), ""}
 		}
 		runs := splitIntoRuns(values)
 		if len(runs) != len(test.output) {