pkg/eval: Remove (*Frame).Eval.

pkg/eval/builtin_fn_misc.go

@@ -332,7 +332,9 @@ func source(fm *Frame, fname string) error {
 	if err != nil {
 		return err
 	}
-	return fm.Eval(op)
+	newFm := fm.fork("[-source]")
+	newFm.srcMeta = src
+	return op.Exec(newFm)
 }
 
 func readFileUTF8(fname string) (string, error) {

pkg/eval/builtin_special.go

@@ -171,6 +171,8 @@ func compileFn(cp *compiler, fn *parse.Form) effectOp {
 	bodyNode := args.nextMustLambda()
 	args.mustEnd()
 
+	// Define the variable before compiling the body, so that the body may refer
+	// to the function itself.
 	index := cp.thisScope().add(name + FnSuffix)
 	op := cp.lambda(bodyNode)
 
@@ -322,7 +324,7 @@ func evalInner(fm *Frame, src parse.Source, ns *Ns, st *StackTrace) error {
 	if err != nil {
 		return err
 	}
-	return newFm.Eval(op)
+	return op.Exec(newFm)
 }
 
 // compileAnd compiles the "and" special form.

pkg/eval/frame.go

@@ -131,17 +131,6 @@ func (fm *Frame) forkWithOutput(name string, p *Port) *Frame {
 	return newFm
 }
 
-// Eval evaluates an Op. It is like eval except that it sets fm.srcMeta
-// temporarily to op.src during the evaluation.
-func (fm *Frame) Eval(op Op) error {
-	oldSrc := fm.srcMeta
-	fm.srcMeta = op.Src
-	defer func() {
-		fm.srcMeta = oldSrc
-	}()
-	return op.Exec(fm)
-}
-
 // CaptureOutput captures the output of a given callback that operates on a Frame.
 func (fm *Frame) CaptureOutput(f func(*Frame) error) ([]interface{}, error) {
 	outPort, collect, err := CapturePort()