tr *Tree
}

func (t *Tree) newNil(pos Pos) *NilNode {
	return &NilNode{tr: t, NodeType: NodeNil, Pos: pos}
}

func (n *NilNode) Type() NodeType {
	// Override method on embedded NodeType for API compatibility.
	// TODO: Not really a problem; could change API without effect but
	// api tool complains.
	return NodeNil
}

func (n *NilNode) String() string {
	return "nil"
}

		t.errorf("missing value for %s", context)
	}
	// Only the first command of a pipeline can start with a non executable operand
	for i, c := range pipe.Cmds[1:] {
		switch c.Args[0].Type() {
		case NodeBool, NodeDot, NodeNil, NodeNumber, NodeString:
			// With A|B|C, pipeline stage 2 is B
			t.errorf("non executable command in pipeline stage %d", i+2)
		}
	}
}

	s.at(chain)
	if len(chain.Field) == 0 {
		s.errorf("internal error: no fields in evalChainNode")
	}
	if chain.Node.Type() == parse.NodeNil {
		s.errorf("indirection through explicit nil in %s", chain)
	}
	// (pipe).Field1.Field2 has pipe as .Node, fields as .Field. Eval the pipeline, then the fields.
	pipe := s.evalArg(dot, nil, chain.Node)

		{"NodeContinue", Const, 18},
		{"NodeDot", Const, 0},
		{"NodeField", Const, 0},
		{"NodeIdentifier", Const, 0},
		{"NodeIf", Const, 0},
		{"NodeList", Const, 0},
		{"NodeNil", Const, 1},
		{"NodeNumber", Const, 0},
		{"NodePipe", Const, 0},
		{"NodeRange", Const, 0},
		{"NodeString", Const, 0},
		{"NodeTemplate", Const, 0},
		{"NodeText", Const, 0},

pkg text/template/parse, const NodeIdentifier = 9
pkg text/template/parse, const NodeIf = 10
pkg text/template/parse, const NodeList = 11
pkg text/template/parse, const NodeNil = 12
pkg text/template/parse, const NodeNil NodeType
pkg text/template/parse, const NodeNumber = 13
pkg text/template/parse, const NodePipe = 14
pkg text/template/parse, const NodeRange = 15