fix: assign binary func to func type var

_test/time10.go

@@ -0,0 +1,13 @@
+package main
+
+import "time"
+
+var UnixTime func(int64, int64) time.Time
+
+func main() {
+	UnixTime = time.Unix
+	println(UnixTime(1e9, 0).In(time.UTC).Minute())
+}
+
+// Output:
+// 46

cmd/goexports/goexports.go

@@ -1,7 +1,7 @@
 //go:generate go build
 
 /*
-Goexports generates wrappers of package exported symbols
+Goexports generates wrappers of package exported symbols.
 
 Output files are written in the current directory, and prefixed with the go version.
 

interp/doc.go

@@ -1,5 +1,5 @@
 /*
-Package interp provides a complete Go interpreter
+Package interp provides a complete Go interpreter.
 
 For the Go language itself, refer to the official Go specification
 https://golang.org/ref/spec.
@@ -32,4 +32,4 @@ And include files containing
 */
 package interp
 
-// BUG(marc): Type checking is not implemented yet
+// BUG(marc): Type checking is not implemented yet.

interp/run.go

@@ -227,6 +227,8 @@ func assign(n *node) {
 			svalue[i] = genInterfaceWrapper(src, dest.typ.rtype)
 		case dest.typ.cat == valueT && src.typ.cat == funcT:
 			svalue[i] = genFunctionWrapper(src)
+		case dest.typ.cat == funcT && src.typ.cat == valueT:
+			svalue[i] = genValueNode(src)
 		case src.kind == basicLit && src.val == nil:
 			t := dest.typ.TypeOf()
 			svalue[i] = func(*frame) reflect.Value { return reflect.New(t).Elem() }
@@ -649,6 +651,29 @@ func call(n *node) {
 
 	n.exec = func(f *frame) bltn {
 		def := value(f).Interface().(*node)
+
+		// Call bin func if defined
+		if def.rval.IsValid() {
+			in := make([]reflect.Value, len(values))
+			for i, v := range values {
+				in[i] = v(f)
+			}
+			if goroutine {
+				go def.rval.Call(in)
+				return tnext
+			}
+			out := def.rval.Call(in)
+			for i, v := range rvalues {
+				if v != nil {
+					v(f).Set(out[i])
+				}
+			}
+			if fnext != nil && !out[0].Bool() {
+				return fnext
+			}
+			return tnext
+		}
+
 		anc := f
 		// Get closure frame context (if any)
 		if def.frame != nil {

interp/value.go

@@ -161,6 +161,14 @@ func genValueInterfaceValue(n *node) func(*frame) reflect.Value {
 	}
 }
 
+func genValueNode(n *node) func(*frame) reflect.Value {
+	value := genValue(n)
+
+	return func(f *frame) reflect.Value {
+		return reflect.ValueOf(&node{rval: value(f)})
+	}
+}
+
 func vInt(v reflect.Value) (i int64) {
 	switch v.Type().Kind() {
 	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64: