support for Timeless FuncValues

Author: gelisam

lang/funcs/structs/util.go

@@ -51,18 +51,9 @@ func SimpleFnToDirectFunc(name string, fv *types.FuncValue) interfaces.Func {
 // *full.FuncValue.
 func SimpleFnToFuncValue(name string, fv *types.FuncValue) *full.FuncValue {
 	return &full.FuncValue{
-		V: func(txn interfaces.Txn, args []interfaces.Func) (interfaces.Func, error) {
-			wrappedFunc := SimpleFnToDirectFunc(name, fv)
-			txn.AddVertex(wrappedFunc)
-			for i, arg := range args {
-				argName := fv.T.Ord[i]
-				txn.AddEdge(arg, wrappedFunc, &interfaces.FuncEdge{
-					Args: []string{argName},
-				})
-			}
-			return wrappedFunc, nil
-		},
-		T: fv.T,
+		Name:     &name,
+		Timeless: fv,
+		T:        fv.T,
 	}
 }
 
@@ -76,9 +67,10 @@ func SimpleFnToConstFunc(name string, fv *types.FuncValue) interfaces.Func {
 // FuncToFullFuncValue creates a *full.FuncValue which adds the given
 // interfaces.Func to the graph. Note that this means the *full.FuncValue
 // can only be called once.
-func FuncToFullFuncValue(valueTransformingFunc interfaces.Func, typ *types.Type) *full.FuncValue {
+func FuncToFullFuncValue(name string, valueTransformingFunc interfaces.Func, typ *types.Type) *full.FuncValue {
 	return &full.FuncValue{
-		V: func(txn interfaces.Txn, args []interfaces.Func) (interfaces.Func, error) {
+		Name: &name,
+		Timeful: func(txn interfaces.Txn, args []interfaces.Func) (interfaces.Func, error) {
 			for i, arg := range args {
 				argName := typ.Ord[i]
 				txn.AddEdge(arg, valueTransformingFunc, &interfaces.FuncEdge{
@@ -90,3 +82,31 @@ func FuncToFullFuncValue(valueTransformingFunc interfaces.Func, typ *types.Type)
 		T: typ,
 	}
 }
+
+// Call calls the function with the provided txn and args.
+func CallFuncValue(obj *full.FuncValue, txn interfaces.Txn, args []interfaces.Func) (interfaces.Func, error) {
+	if obj.Timeful != nil {
+		return obj.Timeful(txn, args)
+	}
+
+	wrappedFunc := SimpleFnToDirectFunc(*obj.Name, obj.Timeless)
+	txn.AddVertex(wrappedFunc)
+	for i, arg := range args {
+		argName := obj.T.Ord[i]
+		txn.AddEdge(arg, wrappedFunc, &interfaces.FuncEdge{
+			Args: []string{argName},
+		})
+	}
+	return wrappedFunc, nil
+}
+
+// Speculatively call the function with the provided arguments.
+// Only makes sense if the function is timeless (produces a single Value, not a
+// stream of values).
+func CallTimelessFuncValue(obj *full.FuncValue, args []types.Value) (types.Value, error) {
+	if obj.Timeless != nil {
+		return obj.Timeless.V(args)
+	}
+
+	panic("cannot call CallIfTimeless on a Timeful function")
+}

lang/types/full/full.go

@@ -41,8 +41,10 @@ import (
 // went horribly wrong. (Think, an internal panic.)
 type FuncValue struct {
 	types.Base
-	V func(interfaces.Txn, []interfaces.Func) (interfaces.Func, error)
-	T *types.Type // contains ordered field types, arg names are a bonus part
+	Name     *string
+	Timeful  func(interfaces.Txn, []interfaces.Func) (interfaces.Func, error)
+	Timeless *types.FuncValue
+	T        *types.Type // contains ordered field types, arg names are a bonus part
 }
 
 // String returns a visual representation of this value.
@@ -111,8 +113,3 @@ func (obj *FuncValue) Value() interface{} {
 	//val := reflect.MakeFunc(typ, fn)
 	//return val.Interface()
 }
-
-// Call calls the function with the provided txn and args.
-func (obj *FuncValue) Call(txn interfaces.Txn, args []interfaces.Func) (interfaces.Func, error) {
-	return obj.V(txn, args)
-}