bind: fwk for protocols. impl __str__

bind/gencpy.go

@@ -248,6 +248,8 @@ func (g *cpyGen) genStruct(cpy Struct) {
 	g.genStructMembers(cpy)
 	g.genStructMethods(cpy)
 
+	g.genStructProtocols(cpy)
+
 	g.impl.Printf("static PyTypeObject _gopy_%sType = {\n", cpy.ID())
 	g.impl.Indent()
 	g.impl.Printf("PyObject_HEAD_INIT(NULL)\n")
@@ -266,7 +268,7 @@ func (g *cpyGen) genStruct(cpy Struct) {
 	g.impl.Printf("0,\t/*tp_as_mapping*/\n")
 	g.impl.Printf("0,\t/*tp_hash */\n")
 	g.impl.Printf("0,\t/*tp_call*/\n")
-	g.impl.Printf("0,\t/*tp_str*/\n")
+	g.impl.Printf("_gopy_%s_tp_str,\t/*tp_str*/\n", cpy.ID())
 	g.impl.Printf("0,\t/*tp_getattro*/\n")
 	g.impl.Printf("0,\t/*tp_setattro*/\n")
 	g.impl.Printf("0,\t/*tp_as_buffer*/\n")
@@ -651,6 +653,39 @@ func (g *cpyGen) genMethodBody(fct Func) {
 	g.genFuncBody(fct)
 }
 
+func (g *cpyGen) genStructProtocols(cpy Struct) {
+	g.genStructTPStr(cpy)
+}
+
+func (g *cpyGen) genStructTPStr(cpy Struct) {
+	g.decl.Printf("static PyObject*\n_gopy_%s_tp_str(PyObject *self);\n", cpy.ID())
+
+	g.impl.Printf("static PyObject*\n_gopy_%s_tp_str(PyObject *self) {\n",
+		cpy.ID(),
+	)
+
+	if (cpy.prots & ProtoStringer) == 0 {
+		g.impl.Indent()
+		g.impl.Printf("return PyObject_Repr(self);\n")
+		g.impl.Outdent()
+		g.impl.Printf("}\n\n")
+		return
+	}
+
+	var m Func
+	for _, f := range cpy.meths {
+		if f.GoName() == "String" {
+			m = f
+			break
+		}
+	}
+
+	g.impl.Indent()
+	g.impl.Printf("return gopy_%[1]s(self, 0);\n", m.ID())
+	g.impl.Outdent()
+	g.impl.Printf("}\n\n")
+}
+
 func (g *cpyGen) genPreamble() {
 	n := g.pkg.pkg.Name()
 	g.decl.Printf(cPreamble, n, g.pkg.pkg.Path(), filepath.Base(n))

bind/package.go

@@ -211,6 +211,9 @@ func (p *Package) process() error {
 				return err
 			}
 			s.meths = append(s.meths, m)
+			if isStringer(meth.Obj()) {
+				s.prots |= ProtoStringer
+			}
 		}
 		p.addStruct(s)
 	}
@@ -248,6 +251,13 @@ func (p *Package) Lookup(o types.Object) (Object, bool) {
 	return obj, ok
 }
 
+// Protocol encodes the various protocols a python type may implement
+type Protocol int
+
+const (
+	ProtoStringer Protocol = 1 << iota
+)
+
 // Struct collects informations about a go struct.
 type Struct struct {
 	pkg *Package
@@ -257,6 +267,8 @@ type Struct struct {
 	doc   string
 	ctors []Func
 	meths []Func
+
+	prots Protocol
 }
 
 func newStruct(p *Package, obj *types.TypeName) (Struct, error) {