boa_parser 0.21.1

use crate::{
    Error,
    lexer::TokenKind,
    parser::{
        AllowAwait, AllowReturn, AllowYield, Cursor, OrAbrupt, ParseResult, TokenParser,
        statement::{ArrayBindingPattern, BindingIdentifier, ObjectBindingPattern, block::Block},
    },
    source::ReadChar,
};
use boa_ast::{
    Keyword, Punctuator, Spanned,
    declaration::Binding,
    operations::{bound_names, lexically_declared_names, var_declared_names},
    statement,
};
use boa_interner::Interner;
use rustc_hash::FxHashSet;

/// Catch parsing
///
/// More information:
///  - [MDN documentation][mdn]
///  - [ECMAScript specification][spec]
///
/// [mdn]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/try...catch
/// [spec]: https://tc39.es/ecma262/#prod-Catch
#[derive(Debug, Clone, Copy)]
pub(super) struct Catch {
    allow_yield: AllowYield,
    allow_await: AllowAwait,
    allow_return: AllowReturn,
}

impl Catch {
    /// Creates a new `Catch` block parser.
    pub(super) fn new<Y, A, R>(allow_yield: Y, allow_await: A, allow_return: R) -> Self
    where
        Y: Into<AllowYield>,
        A: Into<AllowAwait>,
        R: Into<AllowReturn>,
    {
        Self {
            allow_yield: allow_yield.into(),
            allow_await: allow_await.into(),
            allow_return: allow_return.into(),
        }
    }
}

impl<R> TokenParser<R> for Catch
where
    R: ReadChar,
{
    type Output = statement::Catch;

    fn parse(self, cursor: &mut Cursor<R>, interner: &mut Interner) -> ParseResult<Self::Output> {
        cursor.expect((Keyword::Catch, false), "try statement", interner)?;
        let position = cursor.peek(0, interner).or_abrupt()?.span().start();
        let catch_param = if cursor.next_if(Punctuator::OpenParen, interner)?.is_some() {
            let catch_param =
                CatchParameter::new(self.allow_yield, self.allow_await).parse(cursor, interner)?;

            cursor.expect(Punctuator::CloseParen, "catch in try statement", interner)?;
            Some(catch_param)
        } else {
            None
        };

        // It is a Syntax Error if BoundNames of CatchParameter contains any duplicate elements.
        // https://tc39.es/ecma262/#sec-try-statement-static-semantics-early-errors
        let bound_names: Option<FxHashSet<_>> = catch_param
            .as_ref()
            .map(|binding| {
                let mut set = FxHashSet::default();
                for ident in bound_names(binding) {
                    if !set.insert(ident) {
                        return Err(Error::general(
                            "duplicate catch parameter identifier",
                            position,
                        ));
                    }
                }
                Ok(set)
            })
            .transpose()?;

        let position = cursor.peek(0, interner).or_abrupt()?.span().start();
        let catch_block = Block::new(self.allow_yield, self.allow_await, self.allow_return)
            .parse(cursor, interner)?;

        // It is a Syntax Error if any element of the BoundNames of CatchParameter also occurs in the LexicallyDeclaredNames of Block.
        // It is a Syntax Error if any element of the BoundNames of CatchParameter also occurs in the VarDeclaredNames of Block unless CatchParameter is CatchParameter : BindingIdentifier .
        // https://tc39.es/ecma262/#sec-try-statement-static-semantics-early-errors
        // https://tc39.es/ecma262/#sec-variablestatements-in-catch-blocks
        if let Some(bound_names) = bound_names {
            for name in lexically_declared_names(&catch_block) {
                if bound_names.contains(&name) {
                    return Err(Error::general(
                        "catch parameter identifier declared in catch body",
                        position,
                    ));
                }
            }
            if !matches!(&catch_param, Some(Binding::Identifier(_))) {
                for name in var_declared_names(&catch_block) {
                    if bound_names.contains(&name) {
                        return Err(Error::general(
                            "catch parameter identifier declared in catch body",
                            position,
                        ));
                    }
                }
            }
        }

        let catch_node = statement::Catch::new(catch_param, catch_block);
        Ok(catch_node)
    }
}

/// `CatchParameter` parsing
///
/// More information:
///  - [MDN documentation][mdn]
///  - [ECMAScript specification][spec]
///
/// [mdn]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/try...catch
/// [spec]: https://tc39.es/ecma262/#prod-CatchParameter
#[derive(Debug, Clone, Copy)]
pub(super) struct CatchParameter {
    allow_yield: AllowYield,
    allow_await: AllowAwait,
}

impl CatchParameter {
    /// Creates a new `CatchParameter` parser.
    pub(super) fn new<Y, A>(allow_yield: Y, allow_await: A) -> Self
    where
        Y: Into<AllowYield>,
        A: Into<AllowAwait>,
    {
        Self {
            allow_yield: allow_yield.into(),
            allow_await: allow_await.into(),
        }
    }
}

impl<R> TokenParser<R> for CatchParameter
where
    R: ReadChar,
{
    type Output = Binding;

    fn parse(self, cursor: &mut Cursor<R>, interner: &mut Interner) -> ParseResult<Self::Output> {
        let token = cursor.peek(0, interner).or_abrupt()?;

        match token.kind() {
            TokenKind::Punctuator(Punctuator::OpenBlock) => {
                let pat = ObjectBindingPattern::new(self.allow_yield, self.allow_await)
                    .parse(cursor, interner)?;

                Ok(Binding::Pattern(pat.into()))
            }
            TokenKind::Punctuator(Punctuator::OpenBracket) => {
                let pat = ArrayBindingPattern::new(self.allow_yield, self.allow_await)
                    .parse(cursor, interner)?;
                Ok(Binding::Pattern(pat.into()))
            }
            _ => Ok(Binding::Identifier(
                BindingIdentifier::new(self.allow_yield, self.allow_await)
                    .parse(cursor, interner)?,
            )),
        }
    }
}