Refactor events to be interface-based

cmd/reactGen/field_exploder.go

@@ -8,12 +8,19 @@ import (
 	"go/token"
 	"os"
 	"path"
+	"reflect"
 	"strings"
 )
 
 type field struct {
-	Name string
-	Type string
+	TName string
+	Name  string
+	FName string
+	Type  string
+
+	GapBefore bool
+
+	IsEvent bool
 
 	Omit bool
 }
@@ -28,24 +35,12 @@ type fieldExploder struct {
 	imps   map[*ast.ImportSpec]struct{}
 }
 
-func (fe *fieldExploder) explode() error {
-	tf, err := loadStructType(fe.pkgStr, fe.sn)
-	if err != nil {
-		return err
-	}
-
-	if tf == nil {
-		// we can't do any better...
-		return nil
-	}
+func (fe *fieldExploder) explode(tf *typeFile) error {
 
 	st := tf.ts.Type.(*ast.StructType)
 
 	for ind, f := range st.Fields.List {
 		if f.Names == nil {
-			// embedded struct
-			// cannot be a paren expr
-
 			t := f.Type
 
 			if v, ok := t.(*ast.StarExpr); ok {
@@ -96,8 +91,7 @@ func (fe *fieldExploder) explode() error {
 				}
 
 				if !foundImp {
-					// let's move on for now
-					continue
+					return fmt.Errorf("failed to find import %v", x.Name)
 				}
 
 				nfe = &fieldExploder{
@@ -108,47 +102,82 @@ func (fe *fieldExploder) explode() error {
 				}
 			}
 
-			err := nfe.explode()
-			if err != nil {
-				return err
+			tf, err := loadStructType(nfe.pkgStr, nfe.sn)
+			if err == nil && tf != nil {
+				err := nfe.explode(tf)
+				if err != nil {
+					return err
+				}
+
+				fe.fields = append(fe.fields, nfe.fields...)
+				continue
 			}
 
-			fe.fields = append(fe.fields, nfe.fields...)
+		}
 
-		} else {
-			// real fields - we can print the type... but need
-			// to collect the imports first
+		// at this point we know we do _not_ have an embedded
+		// struct type
 
-			newImps := make(map[*ast.ImportSpec]struct{})
+		newImps := make(map[*ast.ImportSpec]struct{})
 
-			i := &importFinder{
-				imports: tf.file.Imports,
-				matches: newImps,
-			}
+		i := &importFinder{
+			imports: tf.file.Imports,
+			matches: newImps,
+		}
 
-			ast.Walk(i, f.Type)
+		ast.Walk(i, f.Type)
 
-			ts := astNodeString(f.Type)
+		ts := astNodeString(f.Type)
 
-			var omit bool
+		var fn string
 
-			if f.Tag != nil {
-				omit = strings.Contains(f.Tag.Value, `react:"omitempty"`)
-			}
+		// TODO we need a more definitive way to ascertain whether
+		// the type of this field is an interface that extends the
+		// Event interface
+		isEvent := strings.HasPrefix(ts, "On")
 
-			if ind == 0 && fe.first && i.isJs {
-				continue
+		// TODO better support for omit based on type of field
+		// need to check vs zero value
+		var omit bool
+
+		if f.Tag != nil {
+			s := reflect.StructTag(strings.Trim(f.Tag.Value, "`"))
+
+			if v, ok := s.Lookup("js"); ok {
+				fn = v
 			}
 
-			for k := range newImps {
-				fe.imps[k] = struct{}{}
+			if v, ok := s.Lookup("react"); ok {
+				omit = v == "omitempty"
 			}
+		}
+
+		if ind == 0 && fe.first && i.isJs {
+			continue
+		}
 
+		for k := range newImps {
+			fe.imps[k] = struct{}{}
+		}
+
+		if len(f.Names) == 0 {
+			fe.fields = append(fe.fields, field{
+				TName:   typeToName(f.Type),
+				FName:   fn,
+				Type:    ts,
+				IsEvent: isEvent,
+				Omit:    omit,
+			})
+
+		} else {
 			for _, n := range f.Names {
 				fe.fields = append(fe.fields, field{
-					Name: n.Name,
-					Type: ts,
-					Omit: omit,
+					Name:    n.Name,
+					TName:   n.Name,
+					FName:   fn,
+					Type:    ts,
+					IsEvent: isEvent,
+					Omit:    omit,
 				})
 			}
 		}
@@ -157,6 +186,19 @@ func (fe *fieldExploder) explode() error {
 	return nil
 }
 
+func typeToName(t ast.Expr) string {
+	switch t := t.(type) {
+	case *ast.Ident:
+		return t.Name
+	case *ast.StarExpr:
+		return typeToName(t.X)
+	case *ast.ParenExpr:
+		return typeToName(t.X)
+	default:
+		panic(fmt.Errorf("don't know how to handle %T", t))
+	}
+}
+
 var pkgCache = make(map[string]*ast.Package)
 
 func loadStructType(pkgStr string, sn string) (*typeFile, error) {

cmd/reactGen/props_gen.go

@@ -14,9 +14,10 @@ import (
 type propsGen struct {
 	*coreGen
 
-	Recv string
-	Name string
-	Doc  string
+	Recv  string
+	Name  string
+	TName string
+	Doc   string
 
 	Fields []field
 }
@@ -50,15 +51,23 @@ func (g *gen) genProps(defName string, t typeFile) {
 		imps:   make(map[*ast.ImportSpec]struct{}),
 	}
 
-	err := fe.explode()
+	err := fe.explode(&t)
 	if err != nil {
 		fatalf("could not explode fields: %v", err)
 	}
 
 	sort.Slice(fe.fields, func(i, j int) bool {
-		return fe.fields[i].Name < fe.fields[j].Name
+		return fe.fields[i].TName < fe.fields[j].TName
 	})
 
+	if len(fe.fields) > 2 {
+		for i := 1; i < len(fe.fields)-1; i++ {
+			if fe.fields[i].IsEvent != fe.fields[i-1].IsEvent {
+				fe.fields[i].GapBefore = true
+			}
+		}
+	}
+
 	pg.Fields = fe.fields
 
 	pg.pf("// Code generated by %v. DO NOT EDIT.\n", reactGenCmd)
@@ -85,24 +94,30 @@ func (g *gen) genProps(defName string, t typeFile) {
 
 	{{.Doc}}
 	type {{.Name}} struct {
-	{{range .Fields}}
-		{{.Name}} {{.Type}}
+	{{range $i, $v := .Fields}}
+		{{if $v.GapBefore}}
+		{{end -}}
+		{{$v.Name}} {{$v.Type}}
 	{{- end}}
 	}
 
 	func ({{$recv}} *{{.Name}}) assign(v *_{{.Name}}) {
 		{{- range .Fields}}
 			{{ if .Omit }}
-				if {{$recv}}.{{.Name}} != "" {
-					v.{{.Name}} = {{$recv}}.{{.Name}}
+				if {{$recv}}.{{.TName}} != "" {
+					v.{{.TName}} = {{$recv}}.{{.TName}}
 				}
 			{{else}}
-			{{if eq .Name "Style"}}
+			{{if .IsEvent}}
+				if {{$recv}}.{{.TName}} != nil {
+					v.o.Set("{{.FName}}", {{$recv}}.{{.TName}}.{{.TName}})
+				}
+			{{else if eq .Name "Style"}}
 				// TODO: until we have a resolution on
 				// https://github.com/gopherjs/gopherjs/issues/236
-				v.{{.Name}} = {{$recv}}.{{.Name}}.hack()
+				v.{{.TName}} = {{$recv}}.{{.TName}}.hack()
 			{{else}}
-				v.{{.Name}} = {{$recv}}.{{.Name}}
+				v.{{.TName}} = {{$recv}}.{{.TName}}
 			{{end}}
 			{{end}}
 		{{- end}}

core.go

@@ -31,8 +31,8 @@ type BasicHTMLElement struct {
 	Role      string `js:"role"`
 	Style     *CSS   `js:"style"`
 
-	OnChange func(e *SyntheticEvent)      `js:"onChange"`
-	OnClick  func(e *SyntheticMouseEvent) `js:"onClick"`
+	OnChange `js:"onChange"`
+	OnClick  `js:"onClick"`
 
 	DangerouslySetInnerHTML *DangerousInnerHTMLDef `js:"dangerouslySetInnerHTML"`
 }

events.go

@@ -0,0 +1,15 @@
+package react
+
+type Event interface{}
+
+type OnChange interface {
+	Event
+
+	OnChange(e *SyntheticEvent)
+}
+
+type OnClick interface {
+	Event
+
+	OnClick(e *SyntheticMouseEvent)
+}

examples/examples.go

@@ -196,23 +196,31 @@ func (p *ExamplesDef) buildExampleNavTab(key exampleKey, t tab, title string) *r
 	return r.Li(
 		lip,
 		r.A(
-			&r.AProps{Href: "#", OnClick: p.handleTabChange(key, t)},
+			&r.AProps{Href: "#", OnClick: tabChange{p, key, t}},
 			r.S(title),
 		),
 	)
 
 }
 
-func (p *ExamplesDef) handleTabChange(key exampleKey, t tab) func(*r.SyntheticMouseEvent) {
-	return func(e *r.SyntheticMouseEvent) {
-		cts := p.State().selectedTabs
-		newSt := p.State()
+type tabChange struct {
+	e   *ExamplesDef
+	key exampleKey
+	t   tab
+}
 
-		newSt.selectedTabs = cts.Set(key, t)
-		p.SetState(newSt)
+func (tc tabChange) OnClick(e *r.SyntheticMouseEvent) {
+	p := tc.e
+	key := tc.key
+	t := tc.t
 
-		e.PreventDefault()
-	}
+	cts := p.State().selectedTabs
+	newSt := p.State()
+
+	newSt.selectedTabs = cts.Set(key, t)
+	p.SetState(newSt)
+
+	e.PreventDefault()
 }
 
 func plainPanel(children ...r.Element) r.Element {

examples/hellomessage/hello_message.go

@@ -1,6 +1,3 @@
-// Copyright (c) 2016 Paul Jolly <paul@myitcv.org.uk>, all rights reserved.
-// Use of this document is governed by a license found in the LICENSE document.
-
 package hellomessage // import "myitcv.io/react/examples/hellomessage"
 
 import (

examples/imm_examples.go

@@ -147,13 +147,33 @@ func (p *ImmExamplesDef) buildExampleNavTab(key exampleKey, t tab, title string)
 	return r.Li(
 		lip,
 		r.A(
-			&r.AProps{Href: "#", OnClick: p.handleTabChange(key, t)},
+			&r.AProps{Href: "#", OnClick: immTabChange{p, key, t}},
 			r.S(title),
 		),
 	)
 
 }
 
+type immTabChange struct {
+	e   *ImmExamplesDef
+	key exampleKey
+	t   tab
+}
+
+func (tc immTabChange) OnClick(e *r.SyntheticMouseEvent) {
+	p := tc.e
+	key := tc.key
+	t := tc.t
+
+	cts := p.State().selectedTabs
+	newSt := p.State()
+
+	newSt.selectedTabs = cts.Set(key, t)
+	p.SetState(newSt)
+
+	e.PreventDefault()
+}
+
 func (p *ImmExamplesDef) handleTabChange(key exampleKey, t tab) func(*r.SyntheticMouseEvent) {
 	return func(e *r.SyntheticMouseEvent) {
 		cts := p.State().selectedTabs