Accept the multiple --type options in order to output the generated code of the multiple types into a single file

Makefile

@@ -12,7 +12,7 @@ build4test: clean
 		-o $(RELEASE_DIR)/gonstructor_test cmd/gonstructor/gonstructor.go
 
 gen4test: build4test
-	rm -f internal/test/*_gen.go
+	rm -f internal/test/*_gen.go internal/test/**/*_gen.go
 	go generate $(PKGS)
 
 test: gen4test

cmd/gonstructor/gonstructor.go

@@ -3,7 +3,6 @@ package main
 import (
 	"flag"
 	"fmt"
-	"io/ioutil"
 	"log"
 	"os"
 	"path/filepath"
@@ -20,29 +19,44 @@ const (
 	builderConstructorType = "builder"
 )
 
-var (
-	typeName          = flag.String("type", "", "[mandatory] a type name")
-	output            = flag.String("output", "", `[optional] output file name (default "srcdir/<type>_gen.go")`)
-	constructorTypes  = flag.String("constructorTypes", allArgsConstructorType, fmt.Sprintf(`[optional] comma-separated list of constructor types; it expects "%s" and "%s"`, allArgsConstructorType, builderConstructorType))
-	shouldShowVersion = flag.Bool("version", false, "[optional] show the version information")
-	withGetter        = flag.Bool("withGetter", false, "[optional] generate a constructor along with getter functions for each field")
-	initFunc          = flag.String("init", "", "[optional] name of function to call on object after creating it")
-)
+type stringArrayFlag []string
+
+func (a *stringArrayFlag) String() string {
+	return strings.Join(*a, ", ")
+}
+
+func (a *stringArrayFlag) Set(item string) error {
+	*a = append(*a, item)
+	return nil
+}
 
 func main() {
+	var typeNames stringArrayFlag
+	flag.Var(&typeNames, "type", `[mandatory] A type name. It accepts this option occurs multiple times to output the generated code of the multi types into a single file. If this option is given multiple times, the "-output" option becomes mandatory.`)
+	output := flag.String("output", "", `[optional] Output file name (default "srcdir/<type>_gen.go"). See also "-type" option's description.'`)
+	constructorTypesStr := flag.String("constructorTypes", allArgsConstructorType, fmt.Sprintf(`[optional] comma-separated list of constructor types; it expects "%s" and "%s"`, allArgsConstructorType, builderConstructorType))
+	shouldShowVersion := flag.Bool("version", false, "[optional] show the version information")
+	withGetter := flag.Bool("withGetter", false, "[optional] generate a constructor along with getter functions for each field")
+	initFunc := flag.String("init", "", "[optional] name of function to call on object after creating it")
+
 	flag.Parse()
 
 	if *shouldShowVersion {
 		internal.ShowVersion()
 		return
 	}
 
-	if *typeName == "" {
+	if len(typeNames) <= 0 {
+		flag.Usage()
+		os.Exit(2)
+	}
+	if len(typeNames) >= 2 && *output == "" {
+		_, _ = fmt.Fprintln(os.Stderr, `[error] if "-type" option appears two or more times, the "-output" option must be specified.`)
 		flag.Usage()
 		os.Exit(2)
 	}
 
-	constructorTypes, err := getConstructorTypes()
+	constructorTypes, err := getConstructorTypes(*constructorTypesStr)
 	if err != nil {
 		log.Printf("[error] %s", err)
 		flag.Usage()
@@ -64,60 +78,82 @@ func main() {
 		log.Fatal(fmt.Errorf("[error] failed to parse a file: %w", err))
 	}
 
-	fields, err := constructor.CollectConstructorFieldsFromAST(*typeName, astFiles)
-	if err != nil {
-		log.Fatal(fmt.Errorf("[error] failed to collect fields from files: %w", err))
-	}
+	fileHeaderGenerated := false
+	for _, typeName := range typeNames {
+		fields, err := constructor.CollectConstructorFieldsFromAST(typeName, astFiles)
+		if err != nil {
+			log.Fatal(fmt.Errorf("[error] failed to collect fields from files: %w", err))
+		}
 
-	rootStmt := g.NewRoot(
-		g.NewComment(fmt.Sprintf(" Code generated by gonstructor %s; DO NOT EDIT.", strings.Join(os.Args[1:], " "))),
-		g.NewNewline(),
-		g.NewPackage(pkg.Name),
-		g.NewNewline(),
-	)
-
-	for _, constructorType := range constructorTypes {
-		var constructorGenerator constructor.Generator
-		switch constructorType {
-		case allArgsConstructorType:
-			constructorGenerator = &constructor.AllArgsConstructorGenerator{
-				TypeName: *typeName,
-				Fields:   fields,
-				InitFunc: *initFunc,
-			}
+		rootStmt := g.NewRoot()
 
-		case builderConstructorType:
-			constructorGenerator = &constructor.BuilderGenerator{
-				TypeName: *typeName,
-				Fields:   fields,
-				InitFunc: *initFunc,
+		if !fileHeaderGenerated {
+			rootStmt = rootStmt.AddStatements(
+				g.NewComment(fmt.Sprintf(" Code generated by gonstructor %s; DO NOT EDIT.", strings.Join(os.Args[1:], " "))),
+				g.NewNewline(),
+				g.NewPackage(pkg.Name),
+				g.NewNewline(),
+			)
+		}
+		fileHeaderGenerated = true
+
+		for _, constructorType := range constructorTypes {
+			var constructorGenerator constructor.Generator
+			switch constructorType {
+			case allArgsConstructorType:
+				constructorGenerator = &constructor.AllArgsConstructorGenerator{
+					TypeName: typeName,
+					Fields:   fields,
+					InitFunc: *initFunc,
+				}
+
+			case builderConstructorType:
+				constructorGenerator = &constructor.BuilderGenerator{
+					TypeName: typeName,
+					Fields:   fields,
+					InitFunc: *initFunc,
+				}
+
+			default:
+				// unreachable, just in case
+				log.Fatalf("[error] unexpected constructor type has come [given=%s]", constructorType)
 			}
 
-		default:
-			// unreachable, just in case
-			log.Fatalf("[error] unexpected constructor type has come [given=%s]", constructorType)
+			rootStmt = rootStmt.AddStatements(constructorGenerator.Generate(0))
 		}
 
-		rootStmt = rootStmt.AddStatements(constructorGenerator.Generate(0))
-	}
+		if *withGetter {
+			rootStmt = rootStmt.AddStatements(internal.GenerateGetters(typeName, fields))
+		}
 
-	if *withGetter {
-		rootStmt = rootStmt.AddStatements(internal.GenerateGetters(*typeName, fields))
-	}
+		code, err := rootStmt.Goimports().EnableSyntaxChecking().Generate(0)
+		if err != nil {
+			log.Fatal(fmt.Errorf("[error] failed to generate code: %w", err))
+		}
 
-	code, err := rootStmt.Goimports().EnableSyntaxChecking().Generate(0)
-	if err != nil {
-		log.Fatal(fmt.Errorf("[error] failed to generate code: %w", err))
-	}
+		err = func() error {
+			f, err := os.OpenFile(getFilenameToGenerate(typeName, *output, args), os.O_APPEND|os.O_WRONLY|os.O_CREATE, 0644)
+			if err != nil {
+				return fmt.Errorf("[error] failed open a file to output the generated code: %w", err)
+			}
 
-	err = ioutil.WriteFile(getFilenameToGenerate(args), []byte(code), 0644)
-	if err != nil {
-		log.Fatal(fmt.Errorf("[error] failed output generated code to a file: %w", err))
+			defer f.Close()
+
+			_, err = f.WriteString(code)
+			if err != nil {
+				return fmt.Errorf("[error] failed output generated code to a file: %w", err)
+			}
+
+			return nil
+		}()
+		if err != nil {
+			log.Fatal(err)
+		}
 	}
 }
 
-func getConstructorTypes() ([]string, error) {
-	typs := strings.Split(*constructorTypes, ",")
+func getConstructorTypes(constructorTypes string) ([]string, error) {
+	typs := strings.Split(constructorTypes, ",")
 	for _, typ := range typs {
 		if typ != allArgsConstructorType && typ != builderConstructorType {
 			return nil, fmt.Errorf("unexpected constructor type has come [given=%s]", typ)
@@ -134,9 +170,9 @@ func isDirectory(name string) bool {
 	return info.IsDir()
 }
 
-func getFilenameToGenerate(args []string) string {
-	if *output != "" {
-		return *output
+func getFilenameToGenerate(typeName string, output string, args []string) string {
+	if output != "" {
+		return output
 	}
 
 	var dir string
@@ -145,5 +181,5 @@ func getFilenameToGenerate(args []string) string {
 	} else {
 		dir = filepath.Dir(args[0])
 	}
-	return fmt.Sprintf("%s/%s_gen.go", dir, strcase.ToSnake(*typeName))
+	return fmt.Sprintf("%s/%s_gen.go", dir, strcase.ToSnake(typeName))
 }

internal/test/multitypes/structure.go

@@ -0,0 +1,13 @@
+package multitypes
+
+//go:generate sh -c "$(cd ./\"$(git rev-parse --show-cdup)\" || exit; pwd)/dist/gonstructor_test --type=AlphaStructure --type=BravoStructure --constructorTypes=allArgs,builder --withGetter --output=./alpha_and_bravo_gen.go"
+
+type AlphaStructure struct {
+	foo string
+	bar int
+}
+
+type BravoStructure struct {
+	buz string
+	qux int
+}

internal/test/multitypes/structure_test.go

@@ -0,0 +1,58 @@
+package multitypes
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestFooAndBarStructureAllArgsConstructor(t *testing.T) {
+	givenFooString := "foo"
+	givenBarInt := 12345
+	givenBuzString := "buz"
+	givenQuxInt := 54321
+
+	gotAlpha := NewAlphaStructure(givenFooString, givenBarInt)
+	gotBravo := NewBravoStructure(givenBuzString, givenQuxInt)
+
+	assert.IsType(t, &AlphaStructure{}, gotAlpha)
+	assert.IsType(t, &BravoStructure{}, gotBravo)
+
+	assert.EqualValues(t, givenFooString, gotAlpha.foo)
+	assert.EqualValues(t, givenBarInt, gotAlpha.bar)
+
+	assert.EqualValues(t, givenBuzString, gotBravo.buz)
+	assert.EqualValues(t, givenQuxInt, gotBravo.qux)
+
+	// test for getters
+	assert.EqualValues(t, givenFooString, gotAlpha.GetFoo())
+	assert.EqualValues(t, givenBarInt, gotAlpha.GetBar())
+
+	assert.EqualValues(t, givenBuzString, gotBravo.GetBuz())
+	assert.EqualValues(t, givenQuxInt, gotBravo.GetQux())
+}
+
+func TestStructureBuilder(t *testing.T) {
+	givenFooString := "foo"
+	givenBarInt := 12345
+	givenBuzString := "buz"
+	givenQuxInt := 54321
+
+	alphaBuilder := NewAlphaStructureBuilder()
+	gotAlpha := alphaBuilder.Foo(givenFooString).
+		Bar(givenBarInt).
+		Build()
+	assert.IsType(t, &AlphaStructure{}, gotAlpha)
+
+	assert.EqualValues(t, givenFooString, gotAlpha.foo)
+	assert.EqualValues(t, givenBarInt, gotAlpha.bar)
+
+	bravoBuilder := NewBravoStructureBuilder()
+	gotBravo := bravoBuilder.Buz(givenBuzString).
+		Qux(givenQuxInt).
+		Build()
+	assert.IsType(t, &BravoStructure{}, gotBravo)
+
+	assert.EqualValues(t, givenBuzString, gotBravo.buz)
+	assert.EqualValues(t, givenQuxInt, gotBravo.qux)
+}