Improve printing of DisplayLists

Use box tree characters to make DisplayLists easier to scan when
printing them out.
This commit is contained in:
Martin Robinson 2015-09-16 11:56:40 -07:00
parent 2879da54f9
commit 30963d76be
5 changed files with 127 additions and 85 deletions

View file

@ -61,6 +61,7 @@ pub mod mem;
pub mod opts;
pub mod persistent_list;
pub mod prefs;
pub mod print_tree;
pub mod range;
pub mod resource_files;
pub mod str;

View file

@ -0,0 +1,59 @@
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
/// A struct that makes it easier to print out a pretty tree of data, which
/// can be visually scanned more easily.
pub struct PrintTree {
/// The current level of recursion.
level: u32,
/// An item which is queued up, so that we can determine if we need
/// a mid-tree prefix or a branch ending prefix.
queued_item: Option<String>,
}
impl PrintTree {
pub fn new(title: String) -> PrintTree {
println!("{}", title);
PrintTree {
level: 1,
queued_item: None,
}
}
/// Descend one level in the tree with the given title.
pub fn new_level(&mut self, title: String) {
self.flush_queued_item("├─");
self.print_level_prefix();
println!("├─ {}", title);
self.level = self.level + 1;
}
/// Ascend one level in the tree.
pub fn end_level(&mut self) {
self.flush_queued_item("└─");
self.level = self.level - 1;
}
/// Add an item to the current level in the tree.
pub fn add_item(&mut self, text: String) {
self.flush_queued_item("├─");
self.queued_item = Some(text);
}
fn print_level_prefix(&self) {
for _ in 0..self.level {
print!("");
}
}
fn flush_queued_item(&mut self, prefix: &str) {
if let Some(queued_item) = self.queued_item.take() {
self.print_level_prefix();
println!("{} {}", prefix, queued_item);
}
}
}