1 // Copyright 2013 The Rust Project Developers. See the COPYRIGHT
2 // file at the top-level directory of this distribution and at
3 // http://rust-lang.org/COPYRIGHT.
5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
8 // option. This file may not be copied, modified, or distributed
9 // except according to those terms.
11 //! Table-of-contents creation.
14 use std::string::String;
16 /// A (recursive) table of contents
19 /// The levels are strictly decreasing, i.e.
21 /// entries[0].level >= entries[1].level >= ...
23 /// Normally they are equal, but can differ in cases like A and B,
24 /// both of which end up in the same `Toc` as they have the same
32 entries: Vec<TocEntry>
36 fn count_entries_with_level(&self, level: u32) -> uint {
37 self.entries.iter().filter(|e| e.level == level).count()
50 /// Progressive construction of a table of contents.
52 pub struct TocBuilder {
54 /// The current hierarchy of parent headings, the levels are
55 /// strictly increasing (i.e. chain[0].level < chain[1].level <
56 /// ...) with each entry being the most recent occurrence of a
57 /// heading with that level (it doesn't include the most recent
58 /// occurrences of every level, just, if *is* in `chain` then is is
59 /// the most recent one).
61 /// We also have `chain[0].level <= top_level.entries[last]`.
66 pub fn new() -> TocBuilder {
67 TocBuilder { top_level: Toc { entries: Vec::new() }, chain: Vec::new() }
71 /// Convert into a true `Toc` struct.
72 pub fn into_toc(mut self) -> Toc {
73 // we know all levels are >= 1.
78 /// Collapse the chain until the first heading more important than
79 /// `level` (i.e. lower level)
94 /// If we are considering H (i.e. level 3), then A and B are in
95 /// self.top_level, D is in C.children, and C, E, F, G are in
98 /// When we attempt to push H, we realise that first G is not the
99 /// parent (level is too high) so it is popped from chain and put
100 /// into F.children, then F isn't the parent (level is equal, aka
101 /// sibling), so it's also popped and put into E.children.
103 /// This leaves us looking at E, which does have a smaller level,
104 /// and, by construction, it's the most recent thing with smaller
105 /// level, i.e. it's the immediate parent of H.
106 fn fold_until(&mut self, level: u32) {
109 match self.chain.pop() {
111 this.map(|e| next.children.entries.push(e));
112 if next.level < level {
113 // this is the parent we want, so return it to
114 // its rightful place.
115 self.chain.push(next);
122 this.map(|e| self.top_level.entries.push(e));
129 /// Push a level `level` heading into the appropriate place in the
130 /// hierarchy, returning a string containing the section number in
131 /// `<num>.<num>.<num>` format.
132 pub fn push<'a>(&'a mut self, level: u32, name: String, id: String) -> &'a str {
135 // collapse all previous sections into their parents until we
136 // get to relevant heading (i.e. the first one with a smaller
138 self.fold_until(level);
142 let (toc_level, toc) = match self.chain.last() {
144 sec_number = String::new();
148 sec_number = String::from_str(entry.sec_number
150 sec_number.push_str(".");
151 (entry.level, &entry.children)
154 // fill in any missing zeros, e.g. for
157 for _ in range(toc_level, level - 1) {
158 sec_number.push_str("0.");
160 let number = toc.count_entries_with_level(level);
161 sec_number.push_str(format!("{}", number + 1).as_slice())
164 self.chain.push(TocEntry {
167 sec_number: sec_number,
169 children: Toc { entries: Vec::new() }
172 // get the thing we just pushed, so we can borrow the string
173 // out of it with the right lifetime
174 let just_inserted = self.chain.last_mut().unwrap();
175 just_inserted.sec_number.as_slice()
179 impl fmt::Show for Toc {
180 fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
181 try!(write!(fmt, "<ul>"));
182 for entry in self.entries.iter() {
183 // recursively format this table of contents (the
184 // `{children}` is the key).
186 "\n<li><a href=\"#{id}\">{num} {name}</a>{children}</li>",
188 num = entry.sec_number, name = entry.name,
189 children = entry.children))
197 use super::{TocBuilder, Toc, TocEntry};
201 let mut builder = TocBuilder::new();
203 // this is purposely not using a fancy macro like below so
204 // that we're sure that this is doing the correct thing, and
205 // there's been no macro mistake.
207 ($level: expr, $name: expr) => {
208 assert_eq!(builder.push($level,
233 push!(6, "3.0.0.1.0.1");
243 ($(($level: expr, $name: expr, $(($sub: tt))* )),*) => {
249 name: $name.to_string(),
250 sec_number: $name.to_string(),
252 children: toc!($($sub),*)
263 ((2, "1.1", ((3, "1.1.1", )) ((3, "1.1.2", ))))
264 ((2, "1.2", ((3, "1.2.1", )) ((3, "1.2.2", ))))
270 ((4, "3.0.0.1", ((6, "3.0.0.1.0.1", ))))
272 ((2, "3.1", ((4, "3.1.0.1", ))))
275 assert_eq!(expected, builder.into_toc());