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|
use super::{is_newline, Scanner};
use crate::syntax::{Ident, RawNode, Span};
/// Resolve all escape sequences in a string.
pub fn resolve_string(string: &str) -> String {
let mut out = String::with_capacity(string.len());
let mut s = Scanner::new(string);
while let Some(c) = s.eat() {
if c != '\\' {
out.push(c);
continue;
}
let start = s.last_index();
match s.eat() {
Some('\\') => out.push('\\'),
Some('"') => out.push('"'),
Some('n') => out.push('\n'),
Some('r') => out.push('\r'),
Some('t') => out.push('\t'),
Some('u') if s.eat_if('{') => {
// TODO: Feedback if closing brace is missing.
let sequence = s.eat_while(|c| c.is_ascii_hexdigit());
let _terminated = s.eat_if('}');
if let Some(c) = resolve_hex(sequence) {
out.push(c);
} else {
// TODO: Feedback that unicode escape sequence is wrong.
out += s.eaten_from(start);
}
}
// TODO: Feedback about invalid escape sequence.
_ => out += s.eaten_from(start),
}
}
out
}
/// Resolve a hexadecimal escape sequence into a character
/// (only the inner hex letters without braces or `\u`).
pub fn resolve_hex(sequence: &str) -> Option<char> {
u32::from_str_radix(sequence, 16).ok().and_then(std::char::from_u32)
}
/// Resolve the language tag and trims the raw text.
pub fn resolve_raw(span: Span, text: &str, backticks: usize) -> RawNode {
if backticks > 1 {
let (tag, inner) = split_at_lang_tag(text);
let (text, block) = trim_and_split_raw(inner);
let lang = Ident::new(tag, span.start .. span.start + tag.len());
RawNode { span, lang, text, block }
} else {
RawNode {
span,
lang: None,
text: split_lines(text).join("\n"),
block: false,
}
}
}
/// Parse the lang tag and return it alongside the remaining inner raw text.
fn split_at_lang_tag(raw: &str) -> (&str, &str) {
let mut s = Scanner::new(raw);
(
s.eat_until(|c| c == '`' || c.is_whitespace() || is_newline(c)),
s.rest(),
)
}
/// Trim raw text and splits it into lines.
///
/// Returns whether at least one newline was contained in `raw`.
fn trim_and_split_raw(mut raw: &str) -> (String, bool) {
// Trims one space at the start.
raw = raw.strip_prefix(' ').unwrap_or(raw);
// Trim one space at the end if the last non-whitespace char is a backtick.
if raw.trim_end().ends_with('`') {
raw = raw.strip_suffix(' ').unwrap_or(raw);
}
let mut lines = split_lines(raw);
let is_whitespace = |line: &String| line.chars().all(char::is_whitespace);
let had_newline = lines.len() > 1;
// Trims a sequence of whitespace followed by a newline at the start.
if lines.first().map_or(false, is_whitespace) {
lines.remove(0);
}
// Trims a newline followed by a sequence of whitespace at the end.
if lines.last().map_or(false, is_whitespace) {
lines.pop();
}
(lines.join("\n"), had_newline)
}
/// Split a string into a vector of lines
/// (respecting Unicode, Unix, Mac and Windows line breaks).
fn split_lines(text: &str) -> Vec<String> {
let mut s = Scanner::new(text);
let mut line = String::new();
let mut lines = Vec::new();
while let Some(c) = s.eat_merging_crlf() {
if is_newline(c) {
lines.push(std::mem::take(&mut line));
} else {
line.push(c);
}
}
lines.push(line);
lines
}
#[cfg(test)]
#[rustfmt::skip]
mod tests {
use crate::syntax::Span;
use super::*;
#[test]
fn test_resolve_strings() {
#[track_caller]
fn test(string: &str, expected: &str) {
assert_eq!(resolve_string(string), expected.to_string());
}
test(r#"hello world"#, "hello world");
test(r#"hello\nworld"#, "hello\nworld");
test(r#"a\"bc"#, "a\"bc");
test(r#"a\u{2603}bc"#, "a☃bc");
test(r#"a\u{26c3bg"#, "a𦰻g");
test(r#"av\u{6797"#, "av林");
test(r#"a\\"#, "a\\");
test(r#"a\\\nbc"#, "a\\\nbc");
test(r#"a\t\r\nbc"#, "a\t\r\nbc");
test(r"🌎", "🌎");
test(r"🌎\", r"🌎\");
test(r"\🌎", r"\🌎");
}
#[test]
fn test_split_at_lang_tag() {
#[track_caller]
fn test(text: &str, lang: &str, inner: &str) {
assert_eq!(split_at_lang_tag(text), (lang, inner));
}
test("typst it!", "typst", " it!");
test("typst\n it!", "typst", "\n it!");
test("typst\n it!", "typst", "\n it!");
test("abc`", "abc", "`");
test(" hi", "", " hi");
test("`", "", "`");
}
#[test]
fn test_resolve_raw() {
#[track_caller]
fn test(
raw: &str,
backticks: usize,
lang: Option<&str>,
text: &str,
block: bool,
) {
Span::without_cmp(|| {
assert_eq!(resolve_raw(Span::ZERO, raw, backticks), RawNode {
span: Span::ZERO,
lang: lang.and_then(|id| Ident::new(id, 0)),
text: text.into(),
block,
});
});
}
// Just one backtick.
test("py", 1, None, "py", false);
test("1\n2", 1, None, "1\n2", false);
test("1\r\n2", 1, None, "1\n2", false);
// More than one backtick with lang tag.
test("js alert()", 2, Some("js"), "alert()", false);
test("py quit(\n\n)", 3, Some("py"), "quit(\n\n)", true);
test("♥", 2, None, "", false);
// Trimming of whitespace (tested more thoroughly in separate test).
test(" a", 2, None, "a", false);
test(" a", 2, None, " a", false);
test(" \na", 2, None, "a", true);
}
#[test]
fn test_trim_raw() {
#[track_caller]
fn test(text: &str, expected: &str) {
assert_eq!(trim_and_split_raw(text).0, expected);
}
test(" hi", "hi");
test(" hi", " hi");
test("\nhi", "hi");
test(" \n hi", " hi");
test("hi` ", "hi`");
test("hi` ", "hi` ");
test("hi` ", "hi` ");
test("hi ", "hi ");
test("hi ", "hi ");
test("hi\n", "hi");
test("hi \n ", "hi ");
test(" \n hi \n ", " hi ");
}
}
|
