259 lines
8.6 KiB
Rust
259 lines
8.6 KiB
Rust
//! Contains the syntax tree nodes that represent the structure of the source code.
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use derive_more::derive::From;
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use getset::Getters;
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use crate::{
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base::{
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self,
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source_file::{SourceElement, Span},
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Handler, VoidHandler,
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},
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lexical::{
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token::{MacroStringLiteral, Punctuation, StringLiteral, Token},
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token_stream::Delimiter,
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},
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syntax::parser::Reading,
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};
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use super::{error::ParseResult, parser::Parser};
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pub mod condition;
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pub mod declaration;
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pub mod expression;
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pub mod program;
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pub mod statement;
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/// Represents a syntax tree node with a pattern of syntax tree nodes separated by a separator.
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///
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/// This struct is useful for representing syntax tree nodes that are separated by a separator.
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/// For example, a comma separated list of expressions such as `1, 2, 3` can be represented by a
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/// [`ConnectedList`] with the separator being a comma token and the elements being the expressions.
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#[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
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#[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord, Hash, Getters)]
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pub struct ConnectedList<Element, Separator> {
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/// The first element of the list.
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#[get = "pub"]
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first: Element,
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/// The rest of the elements of the list.
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///
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/// Each element of the list is a tuple containing the separator and the element. The separator
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/// is the token/syntax tree node that separates the current element from the prior one.
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#[get = "pub"]
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rest: Vec<(Separator, Element)>,
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/// The trailing separator of the list.
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#[get = "pub"]
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trailing_separator: Option<Separator>,
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}
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/// Represents a syntax tree node with a pattern of having [`ConnectedList`] delimited by a pair of
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/// punctuation like such `(a, b, c)`.
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#[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
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#[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
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pub struct DelimitedList<T> {
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/// The open punctuation of the list.
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pub open: Punctuation,
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/// The list of elements of the list.
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///
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/// If `None` then the list is empty (or immediately closed after the open punctuation).
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pub list: Option<ConnectedList<T, Punctuation>>,
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/// The close punctuation of the list.
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pub close: Punctuation,
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}
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/// Represents a syntax tree node that can be either a string literal or a macro string literal.
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///
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/// Syntax Synopsis:
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/// ```ebnf
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/// AnyStringLiteral: StringLiteral | MacroStringLiteral ;
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/// ```
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#[allow(missing_docs)]
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#[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
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#[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord, Hash, From)]
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pub enum AnyStringLiteral {
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StringLiteral(StringLiteral),
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MacroStringLiteral(MacroStringLiteral),
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}
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impl SourceElement for AnyStringLiteral {
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fn span(&self) -> Span {
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match self {
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Self::StringLiteral(string_literal) => string_literal.span(),
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Self::MacroStringLiteral(macro_string_literal) => macro_string_literal.span(),
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}
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}
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}
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impl<'a> Parser<'a> {
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/// Parses a list of elements enclosed by a pair of delimiters, separated by a separator.
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///
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/// The parser position must be at the delimited list of the given delimiter. It will
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/// consume the whole delimited list and move the next token after the list.
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///
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/// # Errors
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/// - if the parser position is not at the delimited list of the given delimiter.
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/// - any error returned by the given parser function.
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pub fn parse_enclosed_list<T>(
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&mut self,
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delimiter: Delimiter,
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separator: char,
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mut f: impl FnMut(&mut Self) -> ParseResult<T>,
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handler: &impl Handler<base::Error>,
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) -> ParseResult<DelimitedList<T>> {
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fn skip_to_next_separator(this: &mut Parser, separator: char) -> Option<Punctuation> {
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if let Reading::Atomic(Token::Punctuation(punc)) = this.stop_at(|token| {
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matches!(
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token, Reading::Atomic(Token::Punctuation(punc))
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if punc.punctuation == separator
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)
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}) {
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this.forward();
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Some(punc)
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} else {
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None
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}
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}
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let delimited_tree = self.step_into(
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delimiter,
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|parser| {
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let mut first = None;
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let mut rest = Vec::new();
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let mut trailing_separator: Option<Punctuation> = None;
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while !parser.is_exhausted() {
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let Ok(element) = f(parser) else {
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skip_to_next_separator(parser, separator);
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continue;
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};
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// adds new element
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match (&first, &trailing_separator) {
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(None, None) => {
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first = Some(element);
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}
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(Some(_), Some(separator)) => {
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rest.push((separator.clone(), element));
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trailing_separator = None;
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}
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_ => {
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unreachable!()
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}
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}
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// expect separator if not exhausted
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if !parser.is_exhausted() {
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let Ok(separator) = parser.parse_punctuation(separator, true, handler)
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else {
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if let Some(punctuation) = skip_to_next_separator(parser, separator) {
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trailing_separator = Some(punctuation);
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}
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continue;
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};
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trailing_separator = Some(separator);
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}
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}
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Ok(first.map(|first| ConnectedList {
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first,
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rest,
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trailing_separator,
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}))
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},
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handler,
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)?;
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Ok(DelimitedList {
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open: delimited_tree.open,
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list: delimited_tree.tree.unwrap(),
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close: delimited_tree.close,
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})
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}
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/// Parses a list of elements separated by a separator.
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///
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/// The parser position must be at the connected list of the first element. It will
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/// consume the whole connected list and move the next token after the list.
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///
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/// # Errors
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/// - if the parser position is not at the connected list of the given element.
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/// - any error returned by the given parser function.
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pub fn parse_connected_list<T>(
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&mut self,
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seperator: char,
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mut f: impl FnMut(&mut Self) -> ParseResult<T>,
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_handler: &impl Handler<base::Error>,
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) -> ParseResult<ConnectedList<T, Punctuation>> {
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let first = f(self)?;
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let mut rest = Vec::new();
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while let Ok(sep) =
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self.try_parse(|parser| parser.parse_punctuation(seperator, true, &VoidHandler))
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{
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if let Ok(element) = self.try_parse(&mut f) {
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rest.push((sep, element));
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} else {
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return Ok(ConnectedList {
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first,
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rest,
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trailing_separator: Some(sep),
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});
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}
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}
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Ok(ConnectedList {
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first,
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rest,
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trailing_separator: None,
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})
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}
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}
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impl<Element: SourceElement, Separator: SourceElement> SourceElement
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for ConnectedList<Element, Separator>
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{
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fn span(&self) -> Span {
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let end = self.trailing_separator.as_ref().map_or_else(
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|| {
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self.rest
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.last()
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.map_or_else(|| self.first.span(), |(_, element)| element.span())
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},
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SourceElement::span,
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);
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self.first.span().join(&end).unwrap()
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}
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}
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impl<Element, Separator> ConnectedList<Element, Separator> {
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/// Returns an iterator over the elements of the list.
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pub fn elements(&self) -> impl Iterator<Item = &Element> {
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std::iter::once(&self.first).chain(self.rest.iter().map(|(_, element)| element))
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}
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/// Returns an iterator over the elements of the list.
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pub fn into_elements(self) -> impl Iterator<Item = Element> {
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std::iter::once(self.first).chain(self.rest.into_iter().map(|(_, element)| element))
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}
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/// Gets the number of elements in the list.
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pub fn len(&self) -> usize {
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self.rest.len() + 1
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}
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/// Returns `true` if the list is empty.
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///
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/// The function will never return `false`.
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pub fn is_empty(&self) -> bool {
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false
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}
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}
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