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|
use crate::*;
macro_rules! opt {
($v:expr) => {|s| Some($v(s)) };
}
pub struct Line {
pub elements: Vec<LineElement>,
}
impl Line {
pub fn from_str(raw_string: &str) -> Self {
fn unlabeled_extern_link(target: String) -> Option<LineElement> {
target.contains("/").then( ||
LineElement::ExternalLink(ExternalLink { target, label:String::new() })
)
}
fn labelled_extern_link(s: String) -> Option<LineElement> {
let (label, target) = match s.split_once("](") {
Some((l, t)) => (l.to_string(), t.to_string()),
None => return None };
if label.contains("]") || target.contains("]") { return None }
Some(LineElement::ExternalLink(ExternalLink { label, target })) }
const DELIMITERS: [(fn(String)->Option<LineElement>, &str, &str, &str); 7] = [
( opt!(LineElement::Bold), "**", "**", "*" ),
( opt!(LineElement::Italic), "_", "_", "_" ),
( opt!(LineElement::Monospace), "`", "`", "`" ),
( opt!(LineElement::Math), "$", "$", "$" ),
( opt!(LineElement::InternalLink), "[[", "]]", "[]" ),
( labelled_extern_link, "[", ")", "[]()" ),
( unlabeled_extern_link, "[", "]", "[]" ),
];
let chars: Vec<char> = raw_string.chars().collect();
let mut elements = Vec::new();
let mut cached_chars = String::new();
let mut i = 0;
let starts_with = |i, p:&str| std::iter::zip(&chars[i..], p.chars()).all(|(a, b)| *a == b);
'outer: while let Some(c) = chars.get(i) {
// Only check for opening delimiters that directly follow a whitespace character.
let follows_whitespace = match chars.get(i.wrapping_sub(1)) {
Some(w) => is_whitespace(w),
None => true,
};
if follows_whitespace {
// Try to parse an opening delimiter.
for (variant, start_delim, end_delim, delim_chars) in DELIMITERS {
// Try to match an opening delimiter with a terminating delimiter.
if starts_with(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();
while e_end <= chars.len() {
e_start += 1; e_end += 1;
let end_is_whitespace =
if let Some(end_char) = chars.get(e_end) {
is_whitespace(end_char)
} else {
e_end == chars.len()
};
// If the terminating delimiter is found, store the normal
// text and the styled text, and continue to the next character.
if end_is_whitespace && starts_with(e_start, end_delim) {
// Check that there is content within the styled string.
let styled_string: String = chars[s_end..e_start].iter().collect();
let non_content_chars: Vec<_> = delim_chars.chars().collect();
if !is_contentful(&styled_string, &non_content_chars) { continue }
if styled_string.len() != styled_string.trim().len() { continue }
let line_element = match variant(styled_string) {
Some(e) => e,
None => continue,
};
// Commit the normal and styled strings.
if !cached_chars.is_empty() {
let normal_string = std::mem::take(&mut cached_chars);
elements.push(LineElement::Normal(normal_string)); }
elements.push(line_element);
i = e_end;
continue 'outer;
}
}
}
}
}
cached_chars.push(*c); i += 1;
}
if !cached_chars.is_empty() {
let normal_string = std::mem::take(&mut cached_chars);
elements.push(LineElement::Normal(normal_string)); }
Self { elements }
}
/// Return only the character content, with none of the styling information.
pub fn as_plain_text(&self) -> String {
let mut string = String::new();
for line_element in &self.elements {
string.push_str(line_element.as_plain_text()) }
return string;
}
}
impl std::fmt::Display for Line {
fn fmt(&self, f: &mut std::fmt::Formatter) -> Result<(), std::fmt::Error> {
for line_element in &self.elements {
write!(f, "{line_element}")?; }
Ok(())
}
}
impl std::fmt::Debug for Line {
fn fmt(&self, f: &mut std::fmt::Formatter) -> Result<(), std::fmt::Error> {
for line_element in &self.elements {
write!(f, "{line_element:?}\n")?; }
Ok(())
}
}
|
