mago-type-syntax 1.41.0

Provides core utilities useful for building lexers and parsers within Mago.
Documentation 
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use mago_allocator::prelude::*;
use mago_database::file::HasFileId;

use crate::cst::CallableTypeParameter;
use crate::cst::CallableTypeParameters;
use crate::cst::CallableTypeReturnType;
use crate::cst::CallableTypeSpecification;
use crate::cst::VariableType;
use crate::error::ParseError;
use crate::parser::internal::parse_type;
use crate::parser::internal::parse_type_with_precedence;
use crate::parser::internal::stream::TypeTokenStream;
use crate::token::TypePrecedence;
use crate::token::TypeTokenKind;

#[inline]
pub fn parse_callable_type_specifications<'arena, A>(
    stream: &mut TypeTokenStream<'arena, A>,
) -> Result<CallableTypeSpecification<'arena>, ParseError>
where
    A: Arena,
{
    Ok(CallableTypeSpecification {
        parameters: CallableTypeParameters {
            left_parenthesis: stream.eat_span(TypeTokenKind::LeftParenthesis)?,
            entries: {
                let mut entries = stream.new_bvec::<CallableTypeParameter<'arena>>();

                while !stream.is_at(TypeTokenKind::RightParenthesis)? {
                    let entry = CallableTypeParameter {
                        parameter_type: {
                            if stream.is_at(TypeTokenKind::Ellipsis)? { None } else { Some(parse_type(stream)?) }
                        },
                        ampersand: if stream.is_at(TypeTokenKind::Ampersand)? {
                            Some(stream.consume_span()?)
                        } else {
                            None
                        },
                        equals: if stream.is_at(TypeTokenKind::Equals)? { Some(stream.consume_span()?) } else { None },
                        ellipsis: if stream.is_at(TypeTokenKind::Ellipsis)? {
                            Some(stream.consume_span()?)
                        } else {
                            None
                        },
                        variable: if stream.is_at(TypeTokenKind::Variable)? {
                            Some(VariableType::from_token(stream.consume()?, stream.file_id()))
                        } else {
                            None
                        },
                        comma: if stream.is_at(TypeTokenKind::Comma)? { Some(stream.consume_span()?) } else { None },
                    };

                    if entry.comma.is_none() {
                        entries.push(entry);
                        break;
                    }

                    entries.push(entry);
                }

                mago_syntax_core::cst::Sequence::new(entries)
            },
            right_parenthesis: stream.eat_span(TypeTokenKind::RightParenthesis)?,
        },
        return_type: if stream.is_at(TypeTokenKind::Colon)? {
            let colon = stream.consume_span()?;
            let ret = parse_type_with_precedence(stream, TypePrecedence::Callable)?;
            Some(CallableTypeReturnType { colon, return_type: stream.alloc(ret) })
        } else {
            None
        },
    })
}

#[inline]
pub fn parse_optional_callable_type_specifications<'arena, A>(
    stream: &mut TypeTokenStream<'arena, A>,
) -> Result<Option<CallableTypeSpecification<'arena>>, ParseError>
where
    A: Arena,
{
    if stream.is_at(TypeTokenKind::LeftParenthesis)? {
        let specifications = parse_callable_type_specifications(stream)?;
        Ok(Some(specifications))
    } else {
        Ok(None)
    }
}