Add the ability to create unexported types from an exported template

This allows one to create an exported template type and create a
non exported type from that template.

Fixes #66

main.go

@@ -37,6 +37,7 @@ func main() {
 		out     = flag.String("out", "", "file to save output to instead of stdout")
 		pkgName = flag.String("pkg", "", "package name for generated files")
 		genTag  = flag.String("tag", "", "build tag that is stripped from output")
+		private = flag.Bool("private", false, "don't export the generated type")
 		prefix  = "https://github.com/metabition/gennylib/raw/master/"
 	)
 	flag.Parse()
@@ -84,23 +85,23 @@ func main() {
 		}
 		r.Body.Close()
 		br := bytes.NewReader(b)
-		err = gen(*in, outputFilename, *pkgName, *genTag, br, typeSets, outWriter)
+		err = gen(*in, outputFilename, *pkgName, *genTag, br, typeSets, outWriter, *private)
 	} else if len(*in) > 0 {
 		var file *os.File
 		file, err = os.Open(*in)
 		if err != nil {
 			fatal(exitcodeSourceFileInvalid, err)
 		}
 		defer file.Close()
-		err = gen(*in, outputFilename, *pkgName, *genTag, file, typeSets, outWriter)
+		err = gen(*in, outputFilename, *pkgName, *genTag, file, typeSets, outWriter, *private)
 	} else {
 		var source []byte
 		source, err = ioutil.ReadAll(os.Stdin)
 		if err != nil {
 			fatal(exitcodeStdinFailed, err)
 		}
 		reader := bytes.NewReader(source)
-		err = gen("stdin", outputFilename, *pkgName, *genTag, reader, typeSets, outWriter)
+		err = gen("stdin", outputFilename, *pkgName, *genTag, reader, typeSets, outWriter, *private)
 	}
 
 	// do the work
@@ -144,12 +145,12 @@ func fatal(code int, a ...interface{}) {
 }
 
 // gen performs the generic generation.
-func gen(filename, outputFilename, pkgName, tag string, in io.ReadSeeker, typesets []map[string]string, out io.Writer) error {
+func gen(filename, outputFilename, pkgName, tag string, in io.ReadSeeker, typesets []map[string]string, out io.Writer, private bool) error {
 
 	var output []byte
 	var err error
 
-	output, err = parse.Generics(filename, outputFilename, pkgName, tag, in, typesets)
+	output, err = parse.Generics(filename, outputFilename, pkgName, tag, in, typesets, private)
 	if err != nil {
 		return err
 	}

parse/parse.go

@@ -38,33 +38,34 @@ var unwantedLinePrefixes = [][]byte{
 	[]byte("//go:generate genny "),
 }
 
-func subIntoLiteral(lit, typeTemplate, specificType string) string {
+func subIntoLiteral(lit, typeTemplate, specificType string, private bool) string {
 	if lit == typeTemplate {
 		return specificType
 	}
 	if !strings.Contains(lit, typeTemplate) {
 		return lit
 	}
-	specificLg := wordify(specificType, true)
-	specificSm := wordify(specificType, false)
+	specificLg := wordify(specificType, true, private)
+	specificSm := wordify(specificType, false, private)
 	result := strings.Replace(lit, typeTemplate, specificLg, -1)
+	fmt.Println(result, specificLg, isExported(lit), lit, specificSm)
 	if strings.HasPrefix(result, specificLg) && !isExported(lit) {
 		return strings.Replace(result, specificLg, specificSm, 1)
 	}
 	return result
 }
 
-func subTypeIntoComment(line, typeTemplate, specificType string) string {
+func subTypeIntoComment(line, typeTemplate, specificType string, private bool) string {
 	var subbed string
 	for _, w := range strings.Fields(line) {
-		subbed = subbed + subIntoLiteral(w, typeTemplate, specificType) + " "
+		subbed = subbed + subIntoLiteral(w, typeTemplate, specificType, private) + " "
 	}
 	return subbed
 }
 
 // Does the heavy lifting of taking a line of our code and
 // sbustituting a type into there for our generic type
-func subTypeIntoLine(line, typeTemplate, specificType string) string {
+func subTypeIntoLine(line, typeTemplate, specificType string, private bool) string {
 	src := []byte(line)
 	var s scanner.Scanner
 	fset := token.NewFileSet()
@@ -76,10 +77,10 @@ func subTypeIntoLine(line, typeTemplate, specificType string) string {
 		if tok == token.EOF {
 			break
 		} else if tok == token.COMMENT {
-			subbed := subTypeIntoComment(lit, typeTemplate, specificType)
+			subbed := subTypeIntoComment(lit, typeTemplate, specificType, private)
 			output = output + subbed + " "
 		} else if tok.IsLiteral() {
-			subbed := subIntoLiteral(lit, typeTemplate, specificType)
+			subbed := subIntoLiteral(lit, typeTemplate, specificType, private)
 			output = output + subbed + " "
 		} else {
 			output = output + tok.String() + " "
@@ -89,7 +90,7 @@ func subTypeIntoLine(line, typeTemplate, specificType string) string {
 }
 
 // typeSet looks like "KeyType: int, ValueType: string"
-func generateSpecific(filename string, in io.ReadSeeker, typeSet map[string]string) ([]byte, error) {
+func generateSpecific(filename string, in io.ReadSeeker, typeSet map[string]string, private bool) ([]byte, error) {
 
 	// ensure we are at the beginning of the file
 	in.Seek(0, os.SEEK_SET)
@@ -143,7 +144,7 @@ func generateSpecific(filename string, in io.ReadSeeker, typeSet map[string]stri
 
 		for t, specificType := range typeSet {
 			if strings.Contains(line, t) {
-				newLine := subTypeIntoLine(line, t, specificType)
+				newLine := subTypeIntoLine(line, t, specificType, private)
 				line = newLine
 			}
 		}
@@ -171,7 +172,7 @@ func generateSpecific(filename string, in io.ReadSeeker, typeSet map[string]stri
 
 // Generics parses the source file and generates the bytes replacing the
 // generic types for the keys map with the specific types (its value).
-func Generics(filename, outputFilename, pkgName, tag string, in io.ReadSeeker, typeSets []map[string]string) ([]byte, error) {
+func Generics(filename, outputFilename, pkgName, tag string, in io.ReadSeeker, typeSets []map[string]string, private bool) ([]byte, error) {
 	var localUnwantedLinePrefixes [][]byte
 	localUnwantedLinePrefixes = append(localUnwantedLinePrefixes, unwantedLinePrefixes...)
 
@@ -184,7 +185,7 @@ func Generics(filename, outputFilename, pkgName, tag string, in io.ReadSeeker, t
 	for _, typeSet := range typeSets {
 
 		// generate the specifics
-		parsed, err := generateSpecific(filename, in, typeSet)
+		parsed, err := generateSpecific(filename, in, typeSet, private)
 		if err != nil {
 			return nil, err
 		}
@@ -266,10 +267,13 @@ func isAlphaNumeric(r rune) bool {
 
 // wordify turns a type into a nice word for function and type
 // names etc.
-func wordify(s string, exported bool) string {
+func wordify(s string, exported, private bool) string {
 	s = strings.TrimRight(s, "{}")
 	s = strings.TrimLeft(s, "*&")
 	s = strings.Replace(s, ".", "", -1)
+	if private {
+		return strings.ToLower(string(s[0])) + s[1:]
+	}
 	if !exported {
 		return s
 	}

parse/parse_int_test.go

@@ -29,7 +29,21 @@ func TestWordify(t *testing.T) {
 		"pack.type":   "Packtype",
 		"*pack.type":  "Packtype",
 	} {
-		assert.Equal(t, wordified, wordify(word, true))
+		assert.Equal(t, wordified, wordify(word, true, false))
+	}
+
+	// Test non exported name generation
+	for word, wordified := range map[string]string{
+		"int":         "int",
+		"*int":        "int",
+		"string":      "string",
+		"*MyType":     "myType",
+		"*myType":     "myType",
+		"interface{}": "interface",
+		"pack.type":   "packtype",
+		"*pack.type":  "packtype",
+	} {
+		assert.Equal(t, wordified, wordify(word, true, true))
 	}
 
 }

parse/parse_test.go

@@ -18,6 +18,7 @@ var tests = []struct {
 	in             string
 	tag            string
 	types          []map[string]string
+	private        bool
 
 	// expectations
 	expectedOut string
@@ -36,6 +37,13 @@ var tests = []struct {
 		types:       []map[string]string{{"Something": "int"}},
 		expectedOut: `test/queue/changed/int_queue.go`,
 	},
+	{
+		filename:    "generic_queue.go",
+		in:          `test/queue/generic_queue.go`,
+		types:       []map[string]string{{"Something": "int"}},
+		expectedOut: `test/queue/int_queue_private.go`,
+		private:     true,
+	},
 	{
 		filename:    "generic_queue.go",
 		in:          `test/queue/generic_queue.go`,
@@ -134,7 +142,7 @@ func TestParse(t *testing.T) {
 		test.in = contents(test.in)
 		test.expectedOut = contents(test.expectedOut)
 
-		bytes, err := parse.Generics(test.filename, test.outputFilename, test.pkgName, test.tag, strings.NewReader(test.in), test.types)
+		bytes, err := parse.Generics(test.filename, test.outputFilename, test.pkgName, test.tag, strings.NewReader(test.in), test.types, test.private)
 
 		// check the error
 		if test.expectedErr == nil {

parse/test/queue/int_queue_private.go

@@ -0,0 +1,22 @@
+// This file was automatically generated by genny.
+// Any changes will be lost if this file is regenerated.
+// see https://github.com/cheekybits/genny
+
+package queue
+
+// intQueue is a queue of ints.
+type intQueue struct {
+	items []int
+}
+
+func NewintQueue() *intQueue {
+	return &intQueue{items: make([]int, 0)}
+}
+func (q *intQueue) Push(item int) {
+	q.items = append(q.items, item)
+}
+func (q *intQueue) Pop() int {
+	item := q.items[0]
+	q.items = q.items[1:]
+	return item
+}