Make a Go Interface instead of a struct for top level objects.

Use a new struct Id as a concrete version of that type.

.gitignore

@@ -5,4 +5,4 @@ program
 examples/foundation/foundation
 examples/foundation/ns
 examples/simple/simple
-examples/simple/simple/ClassOne
+examples/simple/ClassOne

examples/foundation/main.go

@@ -0,0 +1,16 @@
+package main
+
+import (
+	"fmt"
+
+	"gitlab.wow.st/gmp/nswrap/examples/foundation/ns"
+)
+
+func main() {
+	n1 := ns.StringWithUTF8String(ns.CharFromString("hi there"))
+	c1 := n1.CapitalizedString()
+	gs := c1.UTF8String().String()
+	fmt.Println(gs)
+	a := ns.ArrayWithObjects(n1)
+	_ = a
+}

examples/simple/ClassOne/simple.h

@@ -18,5 +18,11 @@ struct stru {int a,b;};
 - (int) hi2:(struct stru*)in;
 - (struct stru) nstru1;
 - (struct stru*) nstru2;
+- (void) hi:(id)in;
+- (void) hi3:(id)in;
 @end
 
+@interface ClassTwo : ClassOne
+{ }
+- (ClassTwo*) init;
+@end

examples/simple/ClassOne/simple.m

@@ -54,6 +54,19 @@
 	ret->b = 10;
 	return ret;
 }
-
+- (void) hi:(id)in
+{
+	NSLog(@"hi");
+}
+- (void) hi3:(id)in
+{
+	NSLog(@"hi");
+}
 @end
 
+@implementation ClassTwo
+- (ClassTwo*) init
+{
+	return [super init];
+}
+@end

examples/simple/nswrap.toml

@@ -1,4 +1,4 @@
 Package = "ClassOne"
 InputFiles = [ "ClassOne/simple.h" ]
-Classes = [ "ClassOne" ]
+Classes = [ "ClassOne","ClassTwo" ]
 Imports = [ "simple.h" ]

main.go

@@ -153,9 +153,9 @@ func Start() (err error) {
 	if err != nil {
 		// If clang fails it still prints out the AST, so we have to run it
 		// again to get the real error.
-		errBody, _ := exec.Command("clang", cargs...).CombinedOutput()
+//		errBody, _ := exec.Command("clang", cargs...).CombinedOutput()
 
-		panic("clang failed: " + err.Error() + ":\n\n" + string(errBody))
+		panic("clang failed: " + err.Error() + ":\n\n")
 	}
 
 	lines := readAST(astPP)

types/convert.go

@@ -12,6 +12,26 @@ var super map[string]string
 //go struct.
 var wrapped map[string]bool
 
+func shouldWrap(gt string) bool {
+	if wrapped == nil {
+		wrapped = make(map[string]bool)
+		return false
+	}
+	return gt != "" && gt[0] == '*' && wrapped[gt[1:]]
+}
+
+//goInterfaces records the names of top level Go interfaces. Pointers to these
+//are dereferenced to bare interface names.
+var goInterfaces map[string]bool
+
+func isGoInterface(gt string) bool {
+	if goInterfaces == nil {
+		goInterfaces = make(map[string]bool)
+		return false
+	}
+	return goInterfaces[gt]
+}
+
 //TypeParameters maps, for each class, a TypedefName to a type, representing
 //the Objective-C type parameters for that class
 var TypeParameters map[string]map[string]string
@@ -109,9 +129,6 @@ func (t *Type) BaseType() *Type {
 		t.Node.BaseType(),
 		t.Class,
 	)
-//	if ret.CType() == ret.Class + " *" { // "instancename"
-//		ret.ctype = ret.Class
-//	}
 	return ret
 }
 
@@ -141,6 +158,9 @@ func _goType(ct string) string {
 	ct = strings.Title(ct)
 	ct = strings.ReplaceAll(ct," ","")
 	ct = strings.ReplaceAll(ct,"Struct","")
+	if len(ct) > 0 && ct[0] == '*' && isGoInterface(ct[1:]) {
+		return ct[1:]
+	}
 	return ct
 }
 
@@ -208,13 +228,26 @@ func (t *Type) GoInterfaceDecl() string {
 		gt = gt[1:] // dereference wrapped types
 	}
 	super := Super(gt)
+	if goInterfaces == nil {
+		goInterfaces = make(map[string]bool)
+	}
 	if super == "" {
-		super = "ptr unsafe.Pointer"
+		goInterfaces[gt] = true
+		return fmt.Sprintf(`
+//%s (%s)
+type %s interface {
+	Ptr() unsafe.Pointer
+}
+`,t.Node.Ctype(),t.BaseType().GoType(),gt)
+	}
+	if isGoInterface(super) {
+		super = "Id"
 	}
 	return fmt.Sprintf(`
 //%s (%s)
 type %s struct { %s }
-`,t.Node.Ctype(),t.BaseType().GoType(),gt,super)
+func (o *%s) Ptr() unsafe.Pointer { return o.ptr }
+`,t.Node.Ctype(),t.BaseType().GoType(),gt,super,gt)
 }
 
 func (t *Type) IsFunction() bool {
@@ -242,12 +275,15 @@ func (t *Type) CToGo(cval string) string { // cast C value to CGo
 func GoToC(name string, pnames []string, rtype *Type, ptypes []*Type) string {
 	var ret strings.Builder
 	rt := rtype.CType()
-	wrap := func(gt string) bool {
-		return gt != "" && gt[0] == '*' && wrapped[gt[1:]]
-	}
 	if rt != "void" {
-		if wrap(rtype.GoType()) {
-			ret.WriteString("	ret := &" + rtype.GoType()[1:] + "{}\n")
+		rtgt := rtype.GoType()
+		if shouldWrap(rtgt) || isGoInterface(rtgt) {
+			if isGoInterface(rtgt) {
+				rtgt = "Id"
+			} else {
+				rtgt = rtgt[1:]
+			}
+			ret.WriteString("	ret := &" + rtgt + "{}\n")
 			ret.WriteString("	ret.ptr = unsafe.Pointer(")
 		} else {
 			ret.WriteString("	return (" + rtype.GoType() + ")(")
@@ -261,8 +297,8 @@ func GoToC(name string, pnames []string, rtype *Type, ptypes []*Type) string {
 	for i := 0; i < len(pnames); i++ {
 		pn,pt := pnames[i],ptypes[i]
 		p := pn
-		if wrap(pt.GoType()) {
-			p = pn + ".ptr"
+		if shouldWrap(pt.GoType()) || isGoInterface(pt.GoType()) {
+			p = pn + ".Ptr()"
 		} else {
 			if pt.Node.IsPointer() {
 				p = "unsafe.Pointer(" + pn + ")"
@@ -275,7 +311,7 @@ func GoToC(name string, pnames []string, rtype *Type, ptypes []*Type) string {
 	ret.WriteString(strings.Join(parms,", "))
 	ret.WriteString(")")
 	if rt != "void" {
-		if wrap(rtype.GoType()) {
+		if shouldWrap(rtype.GoType()) || isGoInterface(rtype.GoType()) {
 			ret.WriteString(`)
 	return ret
 `)

wrap/main.go

@@ -35,6 +35,10 @@ func NewWrapper(debug bool) *Wrapper {
 	ret.cCode.WriteString(`/*
 #cgo CFLAGS: -x objective-c
 #cgo LDFLAGS: -framework Foundation
+`)
+	ret.goTypes.WriteString(`
+type Id struct { ptr unsafe.Pointer }
+func (o *Id) Ptr() unsafe.Pointer { return o.ptr }
 `)
 	return ret
 }
@@ -331,12 +335,12 @@ func (w *Wrapper) processType(tp *types.Type) {
 	if bt.IsFunction() {
 		return
 	}
-	w.goTypes.WriteString(bt.GoTypeDecl())
 	super := types.Super(gt)
 	if super != "" {
 		types.Wrap(super)
 		w.processType(types.NewTypeFromString(super,""))
 	}
+	w.goTypes.WriteString(bt.GoTypeDecl())
 }
 
 func (w *Wrapper) CharHelpers() {