Commit e653280c authored by Austin Clements's avatar Austin Clements

Utilities to bridge native types and functions into

interpreter values.  Also, print nil values properly.

R=rsc
APPROVED=rsc
DELTA=173  (173 added, 0 deleted, 0 changed)
OCL=33837
CL=33973
parent f96099db
// Copyright 2009 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package eval
import (
"log";
"go/token";
"reflect";
)
/*
* Type bridging
*/
var (
evalTypes = make(map[reflect.Type] Type);
nativeTypes = make(map[Type] reflect.Type);
)
// TypeFromNative converts a regular Go type into a the corresponding
// interpreter Type.
func TypeFromNative(t reflect.Type) Type {
if et, ok := evalTypes[t]; ok {
return et;
}
var nt *NamedType;
if t.Name() != "" {
name := t.PkgPath() + "·" + t.Name();
nt = &NamedType{token.Position{}, name, nil, true, make(map[string] Method)};
evalTypes[t] = nt;
}
var et Type;
switch t := t.(type) {
case *reflect.BoolType:
et = BoolType;
case *reflect.Float32Type:
et = Float32Type;
case *reflect.Float64Type:
et = Float64Type;
case *reflect.FloatType:
et = FloatType;
case *reflect.Int16Type:
et = Int16Type;
case *reflect.Int32Type:
et = Int32Type;
case *reflect.Int64Type:
et = Int64Type;
case *reflect.Int8Type:
et = Int8Type;
case *reflect.IntType:
et = IntType;
case *reflect.StringType:
et = StringType;
case *reflect.Uint16Type:
et = Uint16Type;
case *reflect.Uint32Type:
et = Uint32Type;
case *reflect.Uint64Type:
et = Uint64Type;
case *reflect.Uint8Type:
et = Uint8Type;
case *reflect.UintType:
et = UintType;
case *reflect.UintptrType:
et = UintptrType;
case *reflect.ArrayType:
et = NewArrayType(int64(t.Len()), TypeFromNative(t.Elem()));
case *reflect.ChanType:
log.Crashf("%T not implemented", t);
case *reflect.FuncType:
nin := t.NumIn();
// Variadic functions have DotDotDotType at the end
varidic := false;
if nin > 0 {
if _, ok := t.In(nin - 1).(*reflect.DotDotDotType); ok {
varidic = true;
nin--;
}
}
in := make([]Type, nin);
for i := range in {
in[i] = TypeFromNative(t.In(i));
}
out := make([]Type, t.NumOut());
for i := range out {
out[i] = TypeFromNative(t.Out(i));
}
et = NewFuncType(in, varidic, out);
case *reflect.InterfaceType:
log.Crashf("%T not implemented", t);
case *reflect.MapType:
log.Crashf("%T not implemented", t);
case *reflect.PtrType:
et = NewPtrType(TypeFromNative(t.Elem()));
case *reflect.SliceType:
et = NewSliceType(TypeFromNative(t.Elem()));
case *reflect.StructType:
n := t.NumField();
fields := make([]StructField, n);
for i := 0; i < n; i++ {
sf := t.Field(i);
// TODO(austin) What to do about private fields?
fields[i].Name = sf.Name;
fields[i].Type = TypeFromNative(sf.Type);
fields[i].Anonymous = sf.Anonymous;
}
et = NewStructType(fields);
case *reflect.UnsafePointerType:
log.Crashf("%T not implemented", t);
default:
log.Crashf("unexpected reflect.Type: %T", t);
}
if nt != nil {
nt.def = et;
et = nt;
}
nativeTypes[et] = t;
evalTypes[t] = et;
return et;
}
// TypeOfNative returns the interpreter Type of a regular Go value.
func TypeOfNative(v interface {}) Type {
return TypeFromNative(reflect.Typeof(v));
}
/*
* Function bridging
*/
type nativeFunc struct {
fn func([]Value, []Value);
in, out int;
}
func (f *nativeFunc) NewFrame() *Frame {
vars := make([]Value, f.in + f.out);
return &Frame{nil, vars};
}
func (f *nativeFunc) Call(fr *Frame) {
f.fn(fr.Vars[0:f.in], fr.Vars[f.in:f.in+f.out]);
}
// FuncFromNative creates an interpreter function from a native
// function that takes its in and out arguments as slices of
// interpreter Value's. While somewhat inconvenient, this avoids
// value marshalling.
func FuncFromNative(fn func([]Value, []Value), t *FuncType) FuncValue {
return &funcV{&nativeFunc{fn, len(t.In), len(t.Out)}};
}
// FuncFromNativeTyped is like FuncFromNative, but constructs the
// function type from a function pointer using reflection. Typically,
// the type will be given as a nil pointer to a function with the
// desired signature.
func FuncFromNativeTyped(fn func([]Value, []Value), t interface{}) (*FuncType, FuncValue) {
ft := TypeOfNative(t).(*FuncType);
return ft, FuncFromNative(fn, ft);
}
......@@ -433,6 +433,9 @@ type ptrV struct {
}
func (v *ptrV) String() string {
if v.target == nil {
return "<nil>";
}
return "&" + v.target.String();
}
......@@ -482,6 +485,9 @@ type sliceV struct {
}
func (v *sliceV) String() string {
if v.Base == nil {
return "<nil>";
}
res := "{";
for i := int64(0); i < v.Len; i++ {
if i > 0 {
......@@ -513,6 +519,9 @@ type mapV struct {
}
func (v *mapV) String() string {
if v.target == nil {
return "<nil>";
}
res := "map[";
i := 0;
v.target.Iter(func(key interface{}, val Value) bool {
......
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