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branch.go
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branch.go
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// Copyright (C) 2017 Google Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package cst
import (
"io"
)
// Branch is a CST node that can have children.
type Branch struct {
NodeBase
// Children is the slice of child nodes for this Branch.
Children []Node
}
// First returns the first child of the branch, or nil if the branch has no
// children.
func (n *Branch) First() Node {
if n == nil || len(n.Children) == 0 {
return nil
}
return n.Children[0]
}
// Last returns the last child of the branch, or nil if the branch has no
// children.
func (n *Branch) Last() Node {
if n == nil || len(n.Children) == 0 {
return nil
}
return n.Children[len(n.Children)-1]
}
// Tok returns the underlying token of this node.
func (n *Branch) Tok() Token {
tok := Token{}
if len(n.Children) > 0 {
first := n.Children[0].Tok()
last := n.Children[len(n.Children)-1].Tok()
tok = first
tok.End = last.End
}
return tok
}
// Write writes the branch node to the writer w.
func (n *Branch) Write(w io.Writer) error {
if err := n.Pre.Write(w); err != nil {
return err
}
for _, c := range n.Children {
if err := c.Write(w); err != nil {
return err
}
}
return n.Post.Write(w)
}