fw/rt2/rules/field.go

package rules

import (
	"reflect"
)

import (
	"fw/cp/node"
	"fw/rt2"
	"fw/rt2/context"
	"fw/rt2/frame"
	"fw/rt2/scope"
	"ypk/halt"
)

func fieldSeq(in ...IN) (out OUT) {
	f := in[0].frame
	n := rt2.NodeOf(f)
	var left node.Node
	left, _ = rt2.RegOf(f)[n.Left()].(node.Node)
	if left == nil {
		left = n.Left()
	}
	switch l := left.(type) {
	case node.VariableNode, node.ParameterNode:
		sc := rt2.ScopeFor(f, l.Object().Adr())
		sc.Select(l.Object().Adr(), func(v scope.Value) {
			rt2.ValueOf(f.Parent())[n.Adr()] = v.(scope.Record).Get(n.Object().Adr())
			rt2.RegOf(f.Parent())[context.META] = n.Object()
		})
		out = End()
	case node.FieldNode, node.DerefNode:
		rt2.Push(rt2.New(l), f)
		rt2.Assert(f, func(f frame.Frame) (bool, int) {
			_, ok := rt2.ValueOf(f)[l.Adr()].(scope.Record)
			return ok, 60
		})
		out.do = func(in ...IN) OUT {
			v := rt2.ValueOf(in[0].frame)[l.Adr()].(scope.Record)
			rt2.ValueOf(f.Parent())[n.Adr()] = v.Get(n.Object().Adr())
			rt2.RegOf(f.Parent())[context.META] = rt2.RegOf(in[0].frame)[context.META]
			return End()
		}
		out.next = LATER
	case node.GuardNode:
		rt2.Push(rt2.New(l), f)
		rt2.Assert(f, func(f frame.Frame) (bool, int) {
			return rt2.RegOf(f)[n.Left()] != nil, 61
		})
		out.next = LATER
		out.do = fieldSeq
	default:
		halt.As(100, reflect.TypeOf(l))
	}
	return out
}