Utilize go/types for code generation (#47)

internal/code/models.go

@@ -1,52 +1,16 @@
 package code
 
 import (
-	"fmt"
 	"go/types"
 	"reflect"
 )
 
-// Import is a model for package imports
-type Import struct {
-	Name string
-	Path string
-}
-
-// LegacyStructField is a definition of the struct field
-type LegacyStructField struct {
-	Name string
-	Type Type
-	Tag  reflect.StructTag
-}
-
 // StructField is a definition of the struct field
 type StructField struct {
 	Var *types.Var
 	Tag reflect.StructTag
 }
 
-// InterfaceType is a definition of the interface
-type InterfaceType struct {
-}
-
-// Code returns token string in code format
-func (intf InterfaceType) Code() string {
-	return `interface{}`
-}
-
-// Type is an interface for value types
-type Type interface {
-	Code() string
-}
-
-// SimpleType is a type that can be called directly
-type SimpleType string
-
-// Code returns token string in code format
-func (t SimpleType) Code() string {
-	return string(t)
-}
-
 var (
 	TypeBool    = types.Typ[types.Bool]
 	TypeInt     = types.Typ[types.Int]
@@ -55,34 +19,3 @@ var (
 	TypeString  = types.Typ[types.String]
 	TypeError   = types.Universe.Lookup("error").Type()
 )
-
-// ExternalType is a type that is called to another package
-type ExternalType struct {
-	PackageAlias string
-	Name         string
-}
-
-// Code returns token string in code format
-func (t ExternalType) Code() string {
-	return fmt.Sprintf("%s.%s", t.PackageAlias, t.Name)
-}
-
-// PointerType is a model of pointer
-type PointerType struct {
-	ContainedType Type
-}
-
-// Code returns token string in code format
-func (t PointerType) Code() string {
-	return fmt.Sprintf("*%s", t.ContainedType.Code())
-}
-
-// ArrayType is a model of array
-type ArrayType struct {
-	ContainedType Type
-}
-
-// Code returns token string in code format
-func (t ArrayType) Code() string {
-	return fmt.Sprintf("[]%s", t.ContainedType.Code())
-}

internal/codegen/base.go

@@ -3,8 +3,6 @@ package codegen
 import (
 	"fmt"
 	"strings"
-
-	"github.com/sunboyy/repogen/internal/code"
 )
 
 const baseTemplate = `// Code generated by {{.Program}}. DO NOT EDIT.
@@ -18,7 +16,7 @@ import (
 type baseTemplateData struct {
 	Program     string
 	PackageName string
-	Imports     [][]code.Import
+	Imports     [][]Import
 }
 
 func (data baseTemplateData) GenImports() string {
@@ -33,7 +31,7 @@ func (data baseTemplateData) GenImports() string {
 	return strings.Join(sections, "\n\n")
 }
 
-func (data baseTemplateData) generateImportLine(imp code.Import) string {
+func (data baseTemplateData) generateImportLine(imp Import) string {
 	if imp.Name == "" {
 		return fmt.Sprintf("\t\"%s\"", imp.Path)
 	}

internal/codegen/body.go

@@ -2,9 +2,8 @@ package codegen
 
 import (
 	"fmt"
+	"go/types"
 	"strings"
-
-	"github.com/sunboyy/repogen/internal/code"
 )
 
 type FunctionBody []Statement
@@ -37,12 +36,21 @@ func (id Identifier) CodeLines() []string {
 }
 
 type DeclStatement struct {
+	Pkg  *types.Package
 	Name string
-	Type code.Type
+	Type types.Type
+}
+
+func NewDeclStatement(pkg *types.Package, name string, typ types.Type) DeclStatement {
+	return DeclStatement{
+		Pkg:  pkg,
+		Name: name,
+		Type: typ,
+	}
 }
 
 func (stmt DeclStatement) CodeLines() []string {
-	return []string{fmt.Sprintf("var %s %s", stmt.Name, stmt.Type.Code())}
+	return []string{fmt.Sprintf("var %s %s", stmt.Name, TypeToString(stmt.Pkg, stmt.Type))}
 }
 
 type DeclAssignStatement struct {
@@ -105,20 +113,32 @@ func (stmt CallStatement) CodeLines() []string {
 }
 
 type SliceStatement struct {
-	Type   code.Type
+	Pkg    *types.Package
+	Type   types.Type
 	Values []Statement
 }
 
+func NewSliceStatement(pkg *types.Package, typ types.Type, values []Statement) SliceStatement {
+	return SliceStatement{
+		Pkg:    pkg,
+		Type:   typ,
+		Values: values,
+	}
+}
+
 func (stmt SliceStatement) CodeLines() []string {
-	lines := []string{stmt.Type.Code() + "{"}
+	lines := []string{TypeToString(stmt.Pkg, stmt.Type) + "{"}
+
 	for _, value := range stmt.Values {
 		stmtLines := value.CodeLines()
 		stmtLines[len(stmtLines)-1] += ","
 		for _, line := range stmtLines {
 			lines = append(lines, "\t"+line)
 		}
 	}
+
 	lines = append(lines, "}")
+
 	return lines
 }
 

internal/codegen/body_test.go

@@ -1,6 +1,7 @@
 package codegen_test
 
 import (
+	"go/types"
 	"reflect"
 	"testing"
 
@@ -20,10 +21,7 @@ func TestIdentifier(t *testing.T) {
 }
 
 func TestDeclStatement(t *testing.T) {
-	stmt := codegen.DeclStatement{
-		Name: "arrs",
-		Type: code.ArrayType{ContainedType: code.SimpleType("int")},
-	}
+	stmt := codegen.NewDeclStatement(nil, "arrs", types.NewSlice(code.TypeInt))
 	expected := []string{"var arrs []int"}
 
 	actual := stmt.CodeLines()
@@ -139,23 +137,18 @@ func TestCallStatement(t *testing.T) {
 }
 
 func TestSliceStatement(t *testing.T) {
-	stmt := codegen.SliceStatement{
-		Type: code.ArrayType{
-			ContainedType: code.SimpleType("string"),
-		},
-		Values: []codegen.Statement{
-			codegen.Identifier(`"hello"`),
-			codegen.ChainStatement{
-				codegen.CallStatement{
-					FuncName: "GetUser",
-					Params: codegen.StatementList{
-						codegen.Identifier("userID"),
-					},
+	stmt := codegen.NewSliceStatement(nil, types.NewSlice(code.TypeString), []codegen.Statement{
+		codegen.Identifier(`"hello"`),
+		codegen.ChainStatement{
+			codegen.CallStatement{
+				FuncName: "GetUser",
+				Params: codegen.StatementList{
+					codegen.Identifier("userID"),
 				},
-				codegen.Identifier("Name"),
 			},
+			codegen.Identifier("Name"),
 		},
-	}
+	})
 	expected := []string{
 		"[]string{",
 		`	"hello",`,

internal/codegen/builder.go

@@ -4,10 +4,15 @@ import (
 	"bytes"
 	"text/template"
 
-	"github.com/sunboyy/repogen/internal/code"
 	"golang.org/x/tools/imports"
 )
 
+// Import is a model for package imports
+type Import struct {
+	Name string
+	Path string
+}
+
 type Builder struct {
 	// Program defines generator program name in the generated file.
 	Program string
@@ -17,7 +22,7 @@ type Builder struct {
 
 	// Imports defines necessary imports to reduce ambiguity when generating
 	// formatting the raw-generated code.
-	Imports [][]code.Import
+	Imports [][]Import
 
 	implementers []Implementer
 }
@@ -29,7 +34,7 @@ type Implementer interface {
 }
 
 // NewBuilder is a constructor of Builder struct.
-func NewBuilder(program string, packageName string, imports [][]code.Import) *Builder {
+func NewBuilder(program string, packageName string, imports [][]Import) *Builder {
 	return &Builder{
 		Program:     program,
 		PackageName: packageName,

internal/codegen/builder_test.go

@@ -38,7 +38,7 @@ func (u User) IDHex() string {
 `
 
 func TestBuilderBuild(t *testing.T) {
-	builder := codegen.NewBuilder("repogen", "user", [][]code.Import{
+	builder := codegen.NewBuilder("repogen", "user", [][]codegen.Import{
 		{
 			{
 				Name: "_",
@@ -56,23 +56,20 @@ func TestBuilderBuild(t *testing.T) {
 		},
 	})
 	builder.AddImplementer(codegen.StructBuilder{
+		Pkg:  testutils.Pkg,
 		Name: "User",
-		Fields: []code.LegacyStructField{
+		Fields: []code.StructField{
 			{
-				Name: "ID",
-				Type: code.ExternalType{
-					PackageAlias: "primitive",
-					Name:         "ObjectID",
-				},
+				Var: types.NewVar(token.NoPos, nil, "ID", testutils.TypeObjectIDNamed),
 				Tag: `bson:"id" json:"id,omitempty"`,
 			},
 			{
-				Name: "Username",
-				Type: code.SimpleType("string"),
+				Var: types.NewVar(token.NoPos, nil, "Username", code.TypeString),
 			},
 		},
 	})
 	builder.AddImplementer(codegen.FunctionBuilder{
+		Pkg:  testutils.Pkg,
 		Name: "NewUser",
 		Params: types.NewTuple(
 			types.NewVar(token.NoPos, nil, "username", code.TypeString),
@@ -104,7 +101,8 @@ func TestBuilderBuild(t *testing.T) {
 		},
 	})
 	builder.AddImplementer(codegen.MethodBuilder{
-		Receiver: codegen.MethodReceiver{Name: "u", Type: code.SimpleType("User")},
+		Pkg:      testutils.Pkg,
+		Receiver: codegen.MethodReceiver{Name: "u", TypeName: "User"},
 		Name:     "IDHex",
 		Params:   nil,
 		Returns:  []types.Type{code.TypeString},