treew

var pf Prefix
exampleTree(&pf)

Output:

This is some sort of preamble
┌─ Node 1
│  ├─ Node 1.1
│  │  This is more additional text
│  │  for node 1.1.
│  └─ Node 1.2
│     ├─ Node 1.2.1
│     │  By the way, this is what I want to add to 1.2.1!
│     └─ Node 1.2.2
│        └─ Node 1.2.1.1
└─ Node 3
And finally a footer

pf := Prefix{Style: ASCIIStyle()}
exampleTree(&pf)

Output:

This is some sort of preamble
,-- Node 1
|   +-- Node 1.1
|   |   This is more additional text
|   |   for node 1.1.
|   `-- Node 1.2
|       +-- Node 1.2.1
|       |   By the way, this is what I want to add to 1.2.1!
|       `-- Node 1.2.2
|           `-- Node 1.2.1.1
`-- Node 3
And finally a footer

pf := Prefix{Style: ItemStyle()}
exampleTree(&pf)

Output:

This is some sort of preamble
- Node 1
  - Node 1.1
    This is more additional text
    for node 1.1.
  - Node 1.2
    - Node 1.2.1
      By the way, this is what I want to add to 1.2.1!
    - Node 1.2.2
      - Node 1.2.1.1
- Node 3
And finally a footer

w := NewWriter(os.Stdout, nil)
io.WriteString(w, "This is some sort of preamble")
io.WriteString(w.Descend().First(nil), "Node 1")
io.WriteString(w.Descend().Next(nil), `Node 1.1
This is more additional text
for node 1.1.`)
io.WriteString(w.Last(nil), "Node 1.2")
fmt.Fprint(w.Descend().Next(nil), "Node 1.2.1")
fmt.Fprint(w, "By the way, this is what I want to add to 1.2.1!")
fmt.Fprint(w.Last(nil), "Node 1.2.2")
fmt.Fprint(w.Descend().Last(nil), "Node 1.2.2.1")
fmt.Fprint(w.Ascend(3).Last(nil), "Node 3")
fmt.Fprint(w.Ascend(1), "And finally a footer")

Output:

This is some sort of preamble
┌─ Node 1
│  ├─ Node 1.1
│  │  This is more additional text
│  │  for node 1.1.
│  └─ Node 1.2
│     ├─ Node 1.2.1
│     │  By the way, this is what I want to add to 1.2.1!
│     └─ Node 1.2.2
│        └─ Node 1.2.2.1
└─ Node 3
And finally a footer