Updated stringer.go to current version (2018/01)

stringer.go

@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build go1.5
-
 // Stringer is a tool to automate the creation of methods that satisfy the fmt.Stringer
 // interface. Given the name of a (signed or unsigned) integer type T that has constants
 // defined, stringer will create a new self-contained Go source file implementing
@@ -58,8 +56,8 @@
 // where t is the lower-cased name of the first type listed. It can be overridden
 // with the -output flag.
 //
-// ------
+// -----------------
-// This is a patched versin of the original stringer. The original generates source code
+// This is a patched version of the original stringer. The original generates source code
 // using '_' (underscore) as part of generated golang identifiers. This creates a number of
 // golint warnings. The patched version simply leaves the '_' out
 
@@ -87,11 +85,9 @@ import (
 
 var (
 	typeNames   = flag.String("type", "", "comma-separated list of type names; must be set")
-	sql             = flag.Bool("sql", false, "if true, the Scanner and Valuer interface will be implemented.")
-	json            = flag.Bool("json", false, "if true, json marshaling methods will be generated. Default: false")
-	yaml            = flag.Bool("yaml", false, "if true, yaml marshaling methods will be generated. Default: false")
 	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", "", "trim the `prefix` from the generated constant names")
+	linecomment = flag.Bool("linecomment", false, "use line comment text as printed text when present")
 )
 
 // Usage is a replacement usage function for the flags package.
@@ -107,7 +103,7 @@ func Usage() {
 
 func main() {
 	log.SetFlags(0)
-	log.SetPrefix("enumer: ")
+	log.SetPrefix("stringer: ")
 	flag.Usage = Usage
 	flag.Parse()
 	if len(*typeNames) == 0 {
@@ -124,11 +120,11 @@ func main() {
 	}
 
 	// Parse the package once.
-	var (
+	var dir string
-		dir string
+	g := Generator{
-		g   Generator
+		trimPrefix:  *trimprefix,
-	)
+		lineComment: *linecomment,
-
+	}
 	if len(args) == 1 && isDirectory(args[0]) {
 		dir = args[0]
 		g.parsePackageDir(args[0])
@@ -138,23 +134,15 @@ func main() {
 	}
 
 	// Print the header and package clause.
-	g.Printf("// Code generated by \"enumer %s\"; DO NOT EDIT\n", strings.Join(os.Args[1:], " "))
+	g.Printf("// Code generated by \"stringer %s\"; DO NOT EDIT.\n", strings.Join(os.Args[1:], " "))
 	g.Printf("\n")
 	g.Printf("package %s", g.pkg.name)
 	g.Printf("\n")
-	g.Printf("import (\n")
+	g.Printf("import \"strconv\"\n") // Used by all methods.
-	g.Printf("\t\"fmt\"\n")
-	if *sql {
-		g.Printf("\t\"database/sql/driver\"\n")
-	}
-	if *json {
-		g.Printf("\t\"encoding/json\"\n")
-	}
-	g.Printf(")\n")
 
 	// Run generate for each type.
 	for _, typeName := range types {
-		g.generate(typeName, *json, *yaml, *sql, *transformMethod)
+		g.generate(typeName)
 	}
 
 	// Format the output.
@@ -186,6 +174,9 @@ func isDirectory(name string) bool {
 type Generator struct {
 	buf bytes.Buffer // Accumulated output.
 	pkg *Package     // Package we are scanning.
+
+	trimPrefix  string
+	lineComment bool
 }
 
 func (g *Generator) Printf(format string, args ...interface{}) {
@@ -199,6 +190,9 @@ type File struct {
 	// These fields are reset for each type being generated.
 	typeName string  // Name of the constant type.
 	values   []Value // Accumulator for constant values of that type.
+
+	trimPrefix  string
+	lineComment bool
 }
 
 type Package struct {
@@ -255,7 +249,7 @@ func (g *Generator) parsePackage(directory string, names []string, text interfac
 		if !strings.HasSuffix(name, ".go") {
 			continue
 		}
-		parsedFile, err := parser.ParseFile(fs, name, text, 0)
+		parsedFile, err := parser.ParseFile(fs, name, text, parser.ParseComments)
 		if err != nil {
 			log.Fatalf("parsing package: %s: %s", name, err)
 		}
@@ -263,6 +257,8 @@ func (g *Generator) parsePackage(directory string, names []string, text interfac
 		files = append(files, &File{
 			file:        parsedFile,
 			pkg:         g.pkg,
+			trimPrefix:  g.trimPrefix,
+			lineComment: g.lineComment,
 		})
 	}
 	if len(astFiles) == 0 {
@@ -289,24 +285,8 @@ func (pkg *Package) check(fs *token.FileSet, astFiles []*ast.File) {
 	pkg.typesPkg = typesPkg
 }
 
-func (g *Generator) transformValueNames(values []Value, transformMethod string) {
-	var transform func(string) string
-	switch transformMethod {
-	case "snake":
-		transform = toSnakeCase
-	case "kebab":
-		transform = toKebabCase
-	default:
-		return
-	}
-
-	for i := range values {
-		values[i].name = transform(values[i].name)
-	}
-}
-
 // generate produces the String method for the named type.
-func (g *Generator) generate(typeName string, includeJSON, includeYAML, includeSQL bool, transformMethod string) {
+func (g *Generator) generate(typeName string) {
 	values := make([]Value, 0, 100)
 	for _, file := range g.pkg.files {
 		// Set the state for this run of the walker.
@@ -321,9 +301,6 @@ func (g *Generator) generate(typeName string, includeJSON, includeYAML, includeS
 	if len(values) == 0 {
 		log.Fatalf("no values defined for type %s", typeName)
 	}
-
-	g.transformValueNames(values, transformMethod)
-
 	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
@@ -337,26 +314,14 @@ func (g *Generator) generate(typeName string, includeJSON, includeYAML, includeS
 	// being necessary for any realistic example other than bitmasks
 	// is very low. And bitmasks probably deserve their own analysis,
 	// to be done some other day.
-	const runsThreshold = 10
 	switch {
 	case len(runs) == 1:
 		g.buildOneRun(runs, typeName)
-	case len(runs) <= runsThreshold:
+	case len(runs) <= 10:
 		g.buildMultipleRuns(runs, typeName)
 	default:
 		g.buildMap(runs, typeName)
 	}
-
-	g.buildValueToNameMap(runs, typeName, runsThreshold)
-	if includeJSON {
-		g.buildJSONMethods(runs, typeName, runsThreshold)
-	}
-	if includeYAML {
-		g.buildYAMLMethods(runs, typeName, runsThreshold)
-	}
-	if includeSQL {
-		g.addValueAndScanMethod(typeName)
-	}
 }
 
 // splitIntoRuns breaks the values into runs of contiguous sequences.
@@ -406,7 +371,7 @@ func (g *Generator) format() []byte {
 
 // Value represents a declared constant.
 type Value struct {
-	name string // The name of the constant after transformation (i.e. camel case => snake case)
+	name string // The name of the constant.
 	// The value is stored as a bit pattern alone. The boolean tells us
 	// whether to interpret it as an int64 or a uint64; the only place
 	// this matters is when sorting.
@@ -505,6 +470,10 @@ func (f *File) genDecl(node ast.Node) bool {
 				signed: info&types.IsUnsigned == 0,
 				str:    value.String(),
 			}
+			if c := vspec.Comment; f.lineComment && c != nil && len(c.List) == 1 {
+				v.name = strings.TrimSpace(c.Text())
+			}
+			v.name = strings.TrimPrefix(v.name, f.trimPrefix)
 			f.values = append(f.values, v)
 		}
 	}
@@ -534,7 +503,9 @@ func (g *Generator) declareIndexAndNameVars(runs [][]Value, typeName string) {
 	var indexes, names []string
 	for i, run := range runs {
 		index, name := g.createIndexAndNameDecl(run, typeName, fmt.Sprintf("_%d", i))
+		if len(run) != 1 {
 			indexes = append(indexes, index)
+		}
 		names = append(names, name)
 	}
 	g.Printf("const (\n")
@@ -542,12 +513,15 @@ func (g *Generator) declareIndexAndNameVars(runs [][]Value, typeName string) {
 		g.Printf("\t%s\n", name)
 	}
 	g.Printf(")\n\n")
+
+	if len(indexes) > 0 {
 		g.Printf("var (")
 		for _, index := range indexes {
 			g.Printf("\t%s\n", index)
 		}
 		g.Printf(")\n\n")
 	}
+}
 
 // declareIndexAndNameVar is the single-run version of declareIndexAndNameVars
 func (g *Generator) declareIndexAndNameVar(run []Value, typeName string) {
@@ -612,7 +586,7 @@ func (g *Generator) buildOneRun(runs [][]Value, typeName string) {
 //	[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)
+		return "%[1]s(" + strconv.FormatInt(int64(i), 10) + ")"
 	}
 	return _%[1]sName[_%[1]sIndex[i]:_%[1]sIndex[i+1]]
 }
@@ -628,7 +602,7 @@ const stringOneRun = `func (i %[1]s) String() string {
 const stringOneRunWithOffset = `func (i %[1]s) String() string {
 	i -= %[2]s
 	if %[4]si >= %[1]s(len(_%[1]sIndex)-1) {
-		return fmt.Sprintf("%[1]s(%%d)", i + %[2]s)
+		return "%[1]s(" + strconv.FormatInt(int64(i + %[2]s), 10) + ")"
 	}
 	return _%[1]sName[_%[1]sIndex[i] : _%[1]sIndex[i+1]]
 }
@@ -655,7 +629,7 @@ 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 \"%s(\" + strconv.FormatInt(int64(i), 10) + \")\"\n", typeName)
 	g.Printf("\t}\n")
 	g.Printf("}\n")
 }
@@ -682,6 +656,6 @@ const stringMap = `func (i %[1]s) String() string {
 	if str, ok := _%[1]sMap[i]; ok {
 		return str
 	}
-	return fmt.Sprintf("%[1]s(%%d)", i)
+	return "%[1]s(" + strconv.FormatInt(int64(i), 10) + ")"
 }
 `