op: change CallOp to be a return value from MacroOp.Stop

Converting

	macro := op.Record(ops)
	...
	macro.Stop()

	macro.Add()

to

	macro := op.Record(ops)
	...
	call := macro.Stop()

	call.Add(ops)

Which is more general (call.Add can take a different ops than the op.Record
that started it), and enforced the order between Stop and the subsequent Add.

Signed-off-by: Elias Naur <mail@eliasnaur.com>

internal/opconst/ops.go

@@ -8,8 +8,8 @@ type OpType byte
 const firstOpIndex = 200
 
 const (
-	TypeMacroDef OpType = iota + firstOpIndex
-	TypeMacro
+	TypeMacro OpType = iota + firstOpIndex
+	TypeCall
 	TypeTransform
 	TypeLayer
 	TypeInvalidate
@@ -26,12 +26,11 @@ const (
 	TypeAux
 	TypeClip
 	TypeProfile
-	TypeCall
 )
 
 const (
-	TypeMacroDefLen     = 1 + 4 + 4
 	TypeMacroLen        = 1 + 4 + 4
+	TypeCallLen         = 1 + 4 + 4
 	TypeTransformLen    = 1 + 4*2
 	TypeLayerLen        = 1
 	TypeRedrawLen       = 1 + 8
@@ -48,13 +47,12 @@ const (
 	TypeAuxLen          = 1
 	TypeClipLen         = 1 + 4*4
 	TypeProfileLen      = 1
-	TypeCallLen         = 1
 )
 
 func (t OpType) Size() int {
 	return [...]int{
-		TypeMacroDefLen,
 		TypeMacroLen,
+		TypeCallLen,
 		TypeTransformLen,
 		TypeLayerLen,
 		TypeRedrawLen,
@@ -71,7 +69,6 @@ func (t OpType) Size() int {
 		TypeAuxLen,
 		TypeClipLen,
 		TypeProfileLen,
-		TypeCallLen,
 	}[t-firstOpIndex]
 }