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use crate::*;
#[derive(Clone)]
pub struct Line {
pub tokens: Vec<Token>,
}
impl Line {
pub fn from_str(raw_line: &str) -> Self {
let chars: Vec<char> = raw_line.chars().collect();
let mut tokens = Vec::new();
let mut normal_chars = String::new();
let mut i = 0;
// Compare chars from i to a delimiter string.
let compare = |i, p:&str| std::iter::zip(&chars[i..], p.chars())
.all(|(a, b)| *a == b);
'find_token: while let Some(c) = chars.get(i) {
let char_follows_whitespace = match chars.get(i.wrapping_sub(1)) {
Some(w) => is_whitespace(w),
None => true,
};
if char_follows_whitespace {
// Try to parse an opening delimiter.
for (variant, start_delim, end_delim, delim_chars) in DELIMITERS {
let delim_chars: Vec<char> = delim_chars.chars().collect();
// Try to match an opening delimiter with a terminating delimiter.
if compare(i, start_delim) {
let s_end = i + start_delim.chars().count();
let mut e_start = s_end;
let mut e_end = e_start + end_delim.chars().count();
// Scan along chars to find matching end delimiter.
while e_end <= chars.len() {
e_start += 1; e_end += 1;
let followed_by_whitespace = match chars.get(e_end) {
Some(end_char) => is_whitespace(end_char),
None => e_end == chars.len(),
};
// If end delimiter is found, store the token and continue.
if followed_by_whitespace && compare(e_start, end_delim) {
// Check if captured string contains non-delimiter characters.
let captured: String = chars[s_end..e_start].iter().collect();
let no_content = !has_content(&captured, &delim_chars);
let air_bubbles = captured.len() != captured.trim().len();
let token = variant(captured);
if no_content || air_bubbles || token.is_none() { continue }
// Commit the preceding normal token, if any.
if !normal_chars.is_empty() {
let normal = std::mem::take(&mut normal_chars);
tokens.push(Token::Normal(normal));
}
tokens.push(token.unwrap());
i = e_end;
continue 'find_token;
}
}
}
}
}
normal_chars.push(*c);
i += 1;
}
if !normal_chars.is_empty() {
let normal = std::mem::take(&mut normal_chars);
tokens.push(Token::Normal(normal));
}
Self { tokens }
}
}
impl ToString for Line {
fn to_string(&self) -> String {
let mut string = String::new();
for token in &self.tokens {
string.push_str(token.as_ref())
}
return string;
}
}
fn unlabeled_extern_link(path: String) -> Option<Token> {
Some( Token::ExternalLink { path, label:String::new() } )
}
fn labelled_extern_link(s: String) -> Option<Token> {
let (label, path) = match s.split_once("](") {
Some((l, t)) => (l.to_string(), t.to_string()),
None => return None,
};
if label.contains("]") || path.contains("]") { return None }
Some( Token::ExternalLink { label, path } )
}
macro_rules! con {
($v:expr) => {|s| Some($v(s)) };
}
const DELIMITERS: [(fn(String)->Option<Token>, &str, &str, &str); 7] = [
( con!(Token::Bold), "**", "**", "*" ),
( con!(Token::Italic), "_", "_", "_" ),
( con!(Token::Monospace), "`", "`", "`" ),
( con!(Token::Math), "$", "$", "$" ),
( con!(Token::InternalLink), "[[", "]]", "[]" ),
( labelled_extern_link, "[", ")", "[]()" ),
( unlabeled_extern_link, "<", ">", "<>" ),
];
fn is_whitespace(c: &char) -> bool {
c.is_whitespace() || r#".,'"“”_:;-/\()[]{}?"#.contains(*c)
}
/// Check that first and last characters of a string are not delimiters.
fn has_content(s: &str, delimiter_chars: &[char]) -> bool {
let not_delim = |c| match c {
Some(c) => !delimiter_chars.contains(&c),
None => false,
};
not_delim(s.chars().nth(0)) && not_delim(s.chars().last())
}
|
