108 lines
2.6 KiB
Rust
108 lines
2.6 KiB
Rust
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use std::ops::Range;
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use crate::{ParseError, ParseErrorKind};
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#[derive(Debug, Clone, Copy, PartialEq, Eq)]
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pub enum BranchKind {
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/// Expanded by default.
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Expanded,
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/// Folded by default.
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Collapsed,
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}
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impl BranchKind {
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pub fn char(&self) -> char {
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match self {
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BranchKind::Expanded => '-',
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BranchKind::Collapsed => '+',
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}
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}
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}
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#[derive(Debug, Clone, PartialEq, Eq)]
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pub struct BranchEvent {
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pub indent_level: usize,
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pub attributes: Range<usize>,
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pub kind: BranchKind,
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pub kind_span: Range<usize>,
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pub content: Range<usize>,
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}
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#[derive(Debug, Clone, PartialEq, Eq)]
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pub struct Parser<'a> {
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pub input: &'a str,
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pub position: usize,
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}
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impl<'a> Parser<'a> {
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fn current(&self) -> Option<char> {
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self.input[self.position..].chars().next()
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}
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fn advance(&mut self) {
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self.position += self.current().map(|c| c.len_utf8()).unwrap_or(0);
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}
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fn eat_as_long_as(&mut self, c: char) -> usize {
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let mut count = 0;
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while self.current() == Some(c) {
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count += 1;
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self.advance();
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}
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count
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}
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fn eat_until(&mut self, c: char) {
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while self.current() != Some(c) {
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self.advance();
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}
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self.advance();
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}
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pub fn peek_indent_level(&mut self) -> usize {
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let position = self.position;
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let indent_level = self.eat_as_long_as(' ');
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self.position = position;
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indent_level
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}
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pub fn next_branch(&mut self) -> Result<Option<BranchEvent>, ParseError> {
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if self.current().is_none() {
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return Ok(None);
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}
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let indent_level = self.eat_as_long_as(' ');
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// TODO: Configs
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let config_start = self.position;
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let config_end = self.position;
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let kind_start = self.position;
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let kind = match self.current() {
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Some('-') => BranchKind::Expanded,
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Some('+') => BranchKind::Collapsed,
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_ => return Err(ParseErrorKind::BranchKindExpected.at(kind_start..kind_start + 1)),
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};
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self.advance();
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let kind_end = self.position;
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let content_start = self.position;
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loop {
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self.eat_until('\n');
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if let Some('\n') | None = self.current() {
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self.advance();
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break;
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}
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}
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let content_end = self.position;
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Ok(Some(BranchEvent {
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indent_level,
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attributes: config_start..config_end,
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kind,
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kind_span: kind_start..kind_end,
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content: content_start..content_end,
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}))
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}
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}
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