Matthew Maurer | dc6194e | 2020-06-02 11:15:18 -0700 | [diff] [blame] | 1 | //! The preprocessing we apply to doc comments. |
| 2 | //! |
| 3 | //! structopt works in terms of "paragraphs". Paragraph is a sequence of |
| 4 | //! non-empty adjacent lines, delimited by sequences of blank (whitespace only) lines. |
| 5 | |
| 6 | use crate::attrs::Method; |
| 7 | use quote::{format_ident, quote}; |
| 8 | use std::iter; |
| 9 | |
| 10 | pub fn process_doc_comment(lines: Vec<String>, name: &str, preprocess: bool) -> Vec<Method> { |
| 11 | // multiline comments (`/** ... */`) may have LFs (`\n`) in them, |
| 12 | // we need to split so we could handle the lines correctly |
| 13 | // |
| 14 | // we also need to remove leading and trailing blank lines |
| 15 | let mut lines: Vec<&str> = lines |
| 16 | .iter() |
| 17 | .skip_while(|s| is_blank(s)) |
| 18 | .flat_map(|s| s.split('\n')) |
| 19 | .collect(); |
| 20 | |
| 21 | while let Some(true) = lines.last().map(|s| is_blank(s)) { |
| 22 | lines.pop(); |
| 23 | } |
| 24 | |
| 25 | // remove one leading space no matter what |
| 26 | for line in lines.iter_mut() { |
| 27 | if line.starts_with(' ') { |
| 28 | *line = &line[1..]; |
| 29 | } |
| 30 | } |
| 31 | |
| 32 | if lines.is_empty() { |
| 33 | return vec![]; |
| 34 | } |
| 35 | |
| 36 | let short_name = format_ident!("{}", name); |
| 37 | let long_name = format_ident!("long_{}", name); |
| 38 | |
| 39 | if let Some(first_blank) = lines.iter().position(|s| is_blank(s)) { |
| 40 | let (short, long) = if preprocess { |
| 41 | let paragraphs = split_paragraphs(&lines); |
| 42 | let short = paragraphs[0].clone(); |
| 43 | let long = paragraphs.join("\n\n"); |
| 44 | (remove_period(short), long) |
| 45 | } else { |
| 46 | let short = lines[..first_blank].join("\n"); |
| 47 | let long = lines.join("\n"); |
| 48 | (short, long) |
| 49 | }; |
| 50 | |
| 51 | vec![ |
| 52 | Method::new(short_name, quote!(#short)), |
| 53 | Method::new(long_name, quote!(#long)), |
| 54 | ] |
| 55 | } else { |
| 56 | let short = if preprocess { |
| 57 | let s = merge_lines(&lines); |
| 58 | remove_period(s) |
| 59 | } else { |
| 60 | lines.join("\n") |
| 61 | }; |
| 62 | |
| 63 | vec![Method::new(short_name, quote!(#short))] |
| 64 | } |
| 65 | } |
| 66 | |
| 67 | fn split_paragraphs(lines: &[&str]) -> Vec<String> { |
| 68 | let mut last_line = 0; |
| 69 | iter::from_fn(|| { |
| 70 | let slice = &lines[last_line..]; |
| 71 | let start = slice.iter().position(|s| !is_blank(s)).unwrap_or(0); |
| 72 | |
| 73 | let slice = &slice[start..]; |
| 74 | let len = slice |
| 75 | .iter() |
| 76 | .position(|s| is_blank(s)) |
| 77 | .unwrap_or_else(|| slice.len()); |
| 78 | |
| 79 | last_line += start + len; |
| 80 | |
| 81 | if len != 0 { |
| 82 | Some(merge_lines(&slice[..len])) |
| 83 | } else { |
| 84 | None |
| 85 | } |
| 86 | }) |
| 87 | .collect() |
| 88 | } |
| 89 | |
| 90 | fn remove_period(mut s: String) -> String { |
| 91 | if s.ends_with('.') && !s.ends_with("..") { |
| 92 | s.pop(); |
| 93 | } |
| 94 | s |
| 95 | } |
| 96 | |
| 97 | fn is_blank(s: &str) -> bool { |
| 98 | s.trim().is_empty() |
| 99 | } |
| 100 | |
| 101 | fn merge_lines(lines: &[&str]) -> String { |
| 102 | lines.iter().map(|s| s.trim()).collect::<Vec<_>>().join(" ") |
| 103 | } |