knuffel/

grammar.rs

use std::collections::{BTreeSet, BTreeMap};

use chumsky::prelude::*;

use crate::ast::{Literal, TypeName, Node, Value, Integer, Decimal, Radix};
use crate::ast::{SpannedName, SpannedNode, Document};
use crate::span::{Spanned};
use crate::traits::{Span};
use crate::errors::{ParseError as Error, TokenFormat};

use chumsky::combinator::{Map, Then};
use chumsky::chain::Chain;

trait ChainChar<I: Clone, O> {
    type Error;
    fn chain_c<U, P>(
        self,
        other: P
    ) -> Map<Then<Self, P>, fn(_: (O, U)) -> Vec<char>, (O, U)>where
        Self: Sized,
        U: Chain<char>,
        O: Chain<char>,
        P: Parser<I, U, Error = Self::Error>;
}

impl<I: Clone, O, R: Parser<I, O>> ChainChar<I, O> for R {
    type Error = <R as Parser<I, O>>::Error;
    fn chain_c<U, P>(
        self,
        other: P
    ) -> Map<Then<Self, P>, fn(_: (O, U)) -> Vec<char>, (O, U)>where
        Self: Sized,
        U: Chain<char>,
        O: Chain<char>,
        P: Parser<I, U, Error = Self::Error>
    {
        Parser::chain(self, other)
    }
}


fn begin_comment<S: Span>(which: char)
    -> impl Parser<char, (), Error=Error<S>> + Clone
{
    just('/')
    .map_err(|e: Error<S>| e.with_no_expected())
    .ignore_then(just(which).ignored())
}

fn newline<S: Span>() -> impl Parser<char, (), Error=Error<S>> {
    just('\r')
        .or_not()
        .ignore_then(just('\n'))
        .or(just('\r')) // Carriage return
        .or(just('\x0C')) // Form feed
        .or(just('\u{0085}')) // Next line
        .or(just('\u{2028}')) // Line separator
        .or(just('\u{2029}')) // Paragraph separator
        .ignored()
    .map_err(|e: Error<S>| e.with_expected_kind("newline"))
}

fn ws_char<S: Span>() -> impl Parser<char, (), Error=Error<S>> {
    filter(|c| matches!(c,
        '\t' | ' ' | '\u{00a0}' | '\u{1680}' |
        '\u{2000}'..='\u{200A}' |
        '\u{202F}' | '\u{205F}' | '\u{3000}' |
        '\u{FEFF}'
    ))
    .ignored()
}

fn id_char<S: Span>() -> impl Parser<char, char, Error=Error<S>> {
    filter(|c| !matches!(c,
        '\u{0000}'..='\u{0021}' |
        '\\'|'/'|'('|')'|'{'|'}'|'<'|'>'|';'|'['|']'|'='|','|'"' |
        // whitespace, excluding 0x20
        '\u{00a0}' | '\u{1680}' |
        '\u{2000}'..='\u{200A}' |
        '\u{202F}' | '\u{205F}' | '\u{3000}' |
        // newline (excluding <= 0x20)
        '\u{0085}' | '\u{2028}' | '\u{2029}'
    ))
    .map_err(|e: Error<S>| e.with_expected_kind("letter"))
}

fn id_sans_dig<S: Span>() -> impl Parser<char, char, Error=Error<S>> {
    filter(|c| !matches!(c,
        '0'..='9' |
        '\u{0000}'..='\u{0020}' |
        '\\'|'/'|'('|')'|'{'|'}'|'<'|'>'|';'|'['|']'|'='|','|'"' |
        // whitespace, excluding 0x20
        '\u{00a0}' | '\u{1680}' |
        '\u{2000}'..='\u{200A}' |
        '\u{202F}' | '\u{205F}' | '\u{3000}' |
        // newline (excluding <= 0x20)
        '\u{0085}' | '\u{2028}' | '\u{2029}'
    ))
    .map_err(|e: Error<S>| e.with_expected_kind("letter"))
}

fn id_sans_sign_dig<S: Span>() -> impl Parser<char, char, Error=Error<S>> {
    filter(|c| !matches!(c,
        '-'| '+' | '0'..='9' |
        '\u{0000}'..='\u{0020}' |
        '\\'|'/'|'('|')'|'{'|'}'|'<'|'>'|';'|'['|']'|'='|','|'"' |
        // whitespace, excluding 0x20
        '\u{00a0}' | '\u{1680}' |
        '\u{2000}'..='\u{200A}' |
        '\u{202F}' | '\u{205F}' | '\u{3000}' |
        // newline (excluding <= 0x20)
        '\u{0085}' | '\u{2028}' | '\u{2029}'
    ))
    .map_err(|e: Error<S>| e.with_expected_kind("letter"))
}

fn ws<S: Span>() -> impl Parser<char, (), Error=Error<S>> {
    ws_char().repeated().at_least(1).ignored().or(ml_comment())
    .map_err(|e| e.with_expected_kind("whitespace"))
}

fn comment<S: Span>() -> impl Parser<char, (), Error=Error<S>> {
    begin_comment('/')
    .then(take_until(newline().or(end()))).ignored()
}

fn ml_comment<S: Span>() -> impl Parser<char, (), Error=Error<S>> {
    recursive::<_, _, _, _, Error<S>>(|comment| {
        choice((
            comment,
            none_of('*').ignored(),
            just('*').then_ignore(none_of('/').rewind()).ignored(),
        )).repeated().ignored()
        .delimited_by(begin_comment('*'), just("*/"))
    })
    .map_err_with_span(|e, span| {
        if matches!(&e, Error::Unexpected { found: TokenFormat::Eoi, .. }) &&
           span.length() > 2
        {
            e.merge(Error::Unclosed {
                label: "comment",
                opened_at: span.at_start(2),
                opened: "/*".into(),
                expected_at: span.at_end(),
                expected: "*/".into(),
                found: None.into(),
            })
        } else {
            // otherwise opening /* is not matched
            e
        }
    })
}

fn raw_string<S: Span>() -> impl Parser<char, Box<str>, Error=Error<S>> {
    just('r')
        .ignore_then(just('#').repeated().map(|v| v.len()))
        .then_ignore(just('"'))
        .then_with(|sharp_num|
            take_until(
                just('"')
                .ignore_then(just('#').repeated().exactly(sharp_num)
                             .ignored()))
            .map_err_with_span(move |e: Error<S>, span| {
                if matches!(&e, Error::Unexpected {
                    found: TokenFormat::Eoi, .. })
                {
                    e.merge(Error::Unclosed {
                        label: "raw string",
                        opened_at: span.before_start(sharp_num+2),
                        opened: TokenFormat::OpenRaw(sharp_num),
                        expected_at: span.at_end(),
                        expected: TokenFormat::CloseRaw(sharp_num),
                        found: None.into(),
                    })
                } else {
                    e
                }
            })
        )
    .map(|(text, ())| {
        text.into_iter().collect::<String>().into()
    })
}

fn string<S: Span>() -> impl Parser<char, Box<str>, Error=Error<S>> {
    raw_string().or(escaped_string())
}

fn expected_kind(s: &'static str) -> BTreeSet<TokenFormat> {
    [TokenFormat::Kind(s)].into_iter().collect()
}

fn esc_char<S: Span>() -> impl Parser<char, char, Error=Error<S>> {
    filter_map(|span, c| match c {
        '"'|'\\'|'/' => Ok(c),
        'b' => Ok('\u{0008}'),
        'f' => Ok('\u{000C}'),
        'n' => Ok('\n'),
        'r' => Ok('\r'),
        't' => Ok('\t'),
        c => Err(Error::Unexpected {
            label: Some("invalid escape char"),
            span,
            found: c.into(),
            expected: "\"\\/bfnrt".chars().map(|c| c.into()).collect(),
        })
    })
    .or(just('u').ignore_then(
            filter_map(|span, c: char| c.is_digit(16).then(|| c)
                .ok_or_else(|| Error::Unexpected {
                    label: Some("unexpected character"),
                    span,
                    found: c.into(),
                    expected: expected_kind("hexadecimal digit"),
                }))
            .repeated()
            .at_least(1)
            .at_most(6)
            .delimited_by(just('{'), just('}'))
            .try_map(|hex_chars, span| {
                let s = hex_chars.into_iter().collect::<String>();
                let c =
                    u32::from_str_radix(&s, 16).map_err(|e| e.to_string())
                    .and_then(|n| char::try_from(n).map_err(|e| e.to_string()))
                    .map_err(|e| Error::Message {
                        label: Some("invalid character code"),
                        span,
                        message: e.to_string(),
                    })?;
                Ok(c)
            })
            .recover_with(skip_until(['}', '"', '\\'], |_| '\0'))))
}

fn escaped_string<S: Span>() -> impl Parser<char, Box<str>, Error=Error<S>> {
    just('"')
    .ignore_then(
        filter(|&c| c != '"' && c != '\\')
        .or(just('\\').ignore_then(esc_char()))
        .repeated()
        .then_ignore(just('"'))
        .map(|val| val.into_iter().collect::<String>().into())
        .map_err_with_span(|e: Error<S>, span| {
            if matches!(&e, Error::Unexpected { found: TokenFormat::Eoi, .. })
            {
                e.merge(Error::Unclosed {
                    label: "string",
                    opened_at: span.before_start(1),
                    opened: '"'.into(),
                    expected_at: span.at_end(),
                    expected: '"'.into(),
                    found: None.into(),
                })
            } else {
                e
            }
        })
    )
}

fn bare_ident<S: Span>() -> impl Parser<char, Box<str>, Error=Error<S>> {
    let sign = just('+').or(just('-'));
    choice((
        sign.chain(id_sans_dig().chain(id_char().repeated())),
        sign.repeated().exactly(1),
        id_sans_sign_dig().chain(id_char().repeated())
    ))
    .map(|v| v.into_iter().collect()).try_map(|s: String, span| {
        match &s[..] {
            "true" => Err(Error::Unexpected {
                label: Some("keyword"),
                span,
                found: TokenFormat::Token("true"),
                expected: expected_kind("identifier"),
            }),
            "false" => Err(Error::Unexpected {
                label: Some("keyword"),
                span,
                found: TokenFormat::Token("false"),
                expected: expected_kind("identifier"),
            }),
            "null" => Err(Error::Unexpected {
                label: Some("keyword"),
                span,
                found: TokenFormat::Token("null"),
                expected: expected_kind("identifier"),
            }),
            _ => Ok(s.into()),
        }
    })
}

fn ident<S: Span>() -> impl Parser<char, Box<str>, Error=Error<S>> {
    choice((
        // match -123 so `-` will not be treated as an ident by backtracking
        number().map(Err),
        bare_ident().map(Ok),
        string().map(Ok),
    ))
    // when backtracking is not already possible,
    // throw error for numbers (mapped to `Result::Err`)
    .try_map(|res, span| res.map_err(|_| Error::Unexpected {
        label: Some("unexpected number"),
        span,
        found: TokenFormat::Kind("number"),
        expected: expected_kind("identifier"),
    }))
}

fn keyword<S: Span>() -> impl Parser<char, Literal, Error=Error<S>> {
    choice((
        just("null")
            .map_err(|e: Error<S>| e.with_expected_token("null"))
            .to(Literal::Null),
        just("true")
            .map_err(|e: Error<S>| e.with_expected_token("true"))
            .to(Literal::Bool(true)),
        just("false")
            .map_err(|e: Error<S>| e.with_expected_token("false"))
            .to(Literal::Bool(false)),
    ))
}

fn digit<S: Span>(radix: u32) -> impl Parser<char, char, Error=Error<S>> {
    filter(move |c: &char| c.is_digit(radix))
}

fn digits<S: Span>(radix: u32) -> impl Parser<char, Vec<char>, Error=Error<S>> {
    filter(move |c: &char| c == &'_' || c.is_digit(radix)).repeated()
}

fn decimal_number<S: Span>() -> impl Parser<char, Literal, Error=Error<S>> {
    just('-').or(just('+')).or_not()
    .chain_c(digit(10)).chain_c(digits(10))
    .chain_c(
        just('.').chain_c(digit(10)).chain_c(digits(10)).or_not().flatten())
    .chain_c(just('e').or(just('E'))
           .chain_c(just('-').or(just('+')).or_not())
           .chain_c(digits(10)).or_not().flatten())
    .map(|v| {
        let is_decimal = v.iter().any(|c| matches!(c, '.'|'e'|'E'));
        let s: String = v.into_iter().filter(|c| c != &'_').collect();
        if is_decimal {
            Literal::Decimal(Decimal(s.into()))
        } else {
            Literal::Int(Integer(Radix::Dec, s.into()))
        }
    })
}

fn radix_number<S: Span>() -> impl Parser<char, Literal, Error=Error<S>> {
    just('-').or(just('+')).or_not()
    .then_ignore(just('0'))
    .then(choice((
        just('b').ignore_then(
            digit(2).chain(digits(2)).map(|s| (Radix::Bin, s))),
        just('o').ignore_then(
            digit(8).chain(digits(8)).map(|s| (Radix::Oct, s))),
        just('x').ignore_then(
            digit(16).chain(digits(16)).map(|s| (Radix::Hex, s))),
    )))
    .map(|(sign, (radix, value))| {
        let mut s = String::with_capacity(value.len() + sign.map_or(0, |_| 1));
        sign.map(|c| s.push(c));
        s.extend(value.into_iter().filter(|&c| c != '_'));
        Literal::Int(Integer(radix, s.into()))
    })
}

fn number<S: Span>() -> impl Parser<char, Literal, Error=Error<S>> {
    radix_number().or(decimal_number())
}

fn literal<S: Span>() -> impl Parser<char, Literal, Error=Error<S>> {
    choice((
        string().map(Literal::String),
        keyword(),
        number(),
    ))
}

fn type_name<S: Span>() -> impl Parser<char, TypeName, Error=Error<S>> {
    ident().delimited_by(just('('), just(')')).map(TypeName::from_string)
}

fn spanned<T, S, P>(p: P) -> impl Parser<char, Spanned<T, S>, Error=Error<S>>
    where P: Parser<char, T, Error=Error<S>>,
          S: Span,
{
    p.map_with_span(|value, span| Spanned { span, value })
}

fn esc_line<S: Span>() -> impl Parser<char, (), Error=Error<S>> {
    just('\\')
        .ignore_then(ws().repeated())
        .ignore_then(comment().or(newline()))
}

fn node_space<S: Span>() -> impl Parser<char, (), Error=Error<S>> {
    ws().or(esc_line())
}

fn node_terminator<S: Span>() -> impl Parser<char, (), Error=Error<S>> {
    choice((newline(), comment(), just(';').ignored(), end()))
}

enum PropOrArg<S> {
    Prop(SpannedName<S>, Value<S>),
    Arg(Value<S>),
    Ignore,
}

fn type_name_value<S: Span>() -> impl Parser<char, Value<S>, Error=Error<S>> {
    spanned(type_name()).then(spanned(literal()))
    .map(|(type_name, literal)| Value { type_name: Some(type_name), literal })
}

fn value<S: Span>() -> impl Parser<char, Value<S>, Error=Error<S>> {
    type_name_value()
    .or(spanned(literal()).map(|literal| Value { type_name: None, literal }))
}

fn prop_or_arg_inner<S: Span>()
    -> impl Parser<char, PropOrArg<S>, Error=Error<S>>
{
    use PropOrArg::*;
    choice((
        spanned(literal()).then(just('=').ignore_then(value()).or_not())
            .try_map(|(name, value), _| {
                let name_span = name.span;
                match (name.value, value) {
                    (Literal::String(s), Some(value)) => {
                        let name = Spanned {
                            span: name_span,
                            value: s,
                        };
                        Ok(Prop(name, value))
                    }
                    (Literal::Bool(_) | Literal::Null, Some(_)) => {
                        Err(Error::Unexpected {
                            label: Some("unexpected keyword"),
                            span: name_span,
                            found: TokenFormat::Kind("keyword"),
                            expected: [
                                TokenFormat::Kind("identifier"),
                                TokenFormat::Kind("string"),
                            ].into_iter().collect(),
                        })
                    }
                    (Literal::Int(_) | Literal::Decimal(_), Some(_)) => {
                        Err(Error::MessageWithHelp {
                            label: Some("unexpected number"),
                            span: name_span,
                            message: "numbers cannot be used as property names"
                                .into(),
                            help: "consider enclosing in double quotes \"..\"",
                        })
                    }
                    (value, None) => Ok(Arg(Value {
                        type_name: None,
                        literal: Spanned {
                            span: name_span,
                            value,
                        },
                    })),
                }
            }),
        spanned(bare_ident()).then(just('=').ignore_then(value()).or_not())
            .validate(|(name, value), span, emit| {
                if value.is_none() {
                    emit(Error::MessageWithHelp {
                        label: Some("unexpected identifier"),
                        span,
                        message: "identifiers cannot be used as arguments"
                            .into(),
                        help: "consider enclosing in double quotes \"..\"",
                    });
                }
                (name, value)
            })
            .map(|(name, value)| {
                if let Some(value) = value {
                    Prop(name, value)
                } else {
                    // this is invalid, but we already emitted error
                    // in validate() above, so doing a sane fallback
                    Arg(Value {
                        type_name: None,
                        literal: name.map(Literal::String),
                    })
                }
            }),
        type_name_value().map(Arg),
    ))
}

fn prop_or_arg<S: Span>() -> impl Parser<char, PropOrArg<S>, Error=Error<S>> {
    begin_comment('-')
        .ignore_then(node_space().repeated())
        .ignore_then(prop_or_arg_inner())
        .map(|_| PropOrArg::Ignore)
    .or(prop_or_arg_inner())
}

fn line_space<S: Span>() -> impl Parser<char, (), Error=Error<S>> {
    newline().or(ws()).or(comment())
}


fn nodes<S: Span>() -> impl Parser<char, Vec<SpannedNode<S>>, Error=Error<S>> {
    use PropOrArg::*;
    recursive(|nodes: chumsky::recursive::Recursive<char, _, Error<S>>| {
        let braced_nodes =
            just('{')
            .ignore_then(nodes
                .then_ignore(just('}'))
                .map_err_with_span(|e, span| {
                    if matches!(&e, Error::Unexpected {
                        found: TokenFormat::Eoi, .. })
                    {
                        e.merge(Error::Unclosed {
                            label: "curly braces",
                            // we know it's `{` at the start of the span
                            opened_at: span.before_start(1),
                            opened: '{'.into(),
                            expected_at: span.at_end(),
                            expected: '}'.into(),
                            found: None.into(),
                        })
                    } else {
                        e
                    }
                }));

        let node = spanned(type_name()).or_not()
            .then(spanned(ident()))
            .then(
                node_space()
                .repeated().at_least(1)
                .ignore_then(prop_or_arg())
                .repeated()
            )
            .then(node_space().repeated()
                  .ignore_then(begin_comment('-')
                               .then_ignore(node_space().repeated())
                               .or_not())
                  .then(spanned(braced_nodes))
                  .or_not())
            .then_ignore(node_space().repeated().then(node_terminator()))
            .map(|(((type_name, node_name), line_items), opt_children)| {
                let mut node = Node {
                    type_name,
                    node_name,
                    properties: BTreeMap::new(),
                    arguments: Vec::new(),
                    children: match opt_children {
                        Some((Some(_comment), _)) => None,
                        Some((None, children)) => Some(children),
                        None => None,
                    },
                };
                for item in line_items {
                    match item {
                        Prop(name, value) => {
                            node.properties.insert(name, value);
                        }
                        Arg(value) => {
                            node.arguments.push(value);
                        }
                        Ignore => {}
                    }
                }
                node
            });

        begin_comment('-').then_ignore(node_space().repeated()).or_not()
        .then(spanned(node))
            .separated_by(line_space().repeated())
            .allow_leading().allow_trailing()
            .map(|vec| vec.into_iter().filter_map(|(comment, node)| {
                if comment.is_none() {
                    Some(node)
                } else {
                    None
                }
            }).collect())
    })
}

pub(crate) fn document<S: Span>()
    -> impl Parser<char, Document<S>, Error=Error<S>>
{
    nodes().then_ignore(end()).map(|nodes| Document { nodes })
}

#[cfg(test)]
mod test {
    use chumsky::prelude::*;
    use miette::NamedSource;
    use crate::errors::{ParseError, Error};
    use crate::span::Span;
    use crate::ast::{Literal, TypeName, Radix, Decimal, Integer};
    use crate::traits::sealed::Sealed;
    use super::{ws, comment, ml_comment, string, ident, literal, type_name};
    use super::{nodes, number};

    macro_rules! err_eq {
        ($left: expr, $right: expr) => {
            let left = $left.unwrap_err();
            let left: serde_json::Value = serde_json::from_str(&left).unwrap();
            let right: serde_json::Value =
                serde_json::from_str($right).unwrap();
            assert_json_diff::assert_json_include!(
                actual: left, expected: right);
            //assert_json_diff::assert_json_eq!(left, right);
        }
    }

    fn parse<'x, P, T>(p: P, text: &'x str) -> Result<T, String>
        where P: Parser<char, T, Error=ParseError<Span>>
    {
        p.then_ignore(end())
        .parse(Span::stream(text)).map_err(|errors| {
            let source = text.to_string() + " ";
            let e = Error {
                source_code: NamedSource::new("<test>", source),
                errors: errors.into_iter().map(Into::into).collect(),
            };
            let mut buf = String::with_capacity(512);
            miette::GraphicalReportHandler::new()
                .render_report(&mut buf, &e).unwrap();
            println!("{}", buf);
            buf.truncate(0);
            miette::JSONReportHandler::new()
                .render_report(&mut buf, &e).unwrap();
            return buf;
        })
    }

    #[test]
    fn parse_ws() {
        parse(ws(), "   ").unwrap();
        parse(ws(), "text").unwrap_err();
    }

    #[test]
    fn parse_comments() {
        parse(comment(), "//hello").unwrap();
        parse(comment(), "//hello\n").unwrap();
        parse(ml_comment(), "/*nothing*/").unwrap();
        parse(ml_comment(), "/*nothing**/").unwrap();
        parse(ml_comment(), "/*no*thing*/").unwrap();
        parse(ml_comment(), "/*no/**/thing*/").unwrap();
        parse(ml_comment(), "/*no/*/**/*/thing*/").unwrap();
        parse(ws().then(comment()), "   // hello").unwrap();
        parse(ws().then(comment()).then(ws()).then(comment()),
              "   // hello\n   //world").unwrap();
    }

    #[test]
    fn parse_comment_err() {
        err_eq!(parse(ws(), r#"/* comment"#), r#"{
            "message": "error parsing KDL",
            "severity": "error",
            "labels": [],
            "related": [{
                "message": "unclosed comment `/*`",
                "severity": "error",
                "filename": "<test>",
                "labels": [
                    {"label": "opened here",
                    "span": {"offset": 0, "length": 2}},
                    {"label": "expected `*/`",
                    "span": {"offset": 10, "length": 0}}
                ],
                "related": []
            }]
        }"#);
        err_eq!(parse(ws(), r#"/* com/*ment *"#), r#"{
            "message": "error parsing KDL",
            "severity": "error",
            "labels": [],
            "related": [{
                "message": "unclosed comment `/*`",
                "severity": "error",
                "filename": "<test>",
                "labels": [
                    {"label": "opened here",
                    "span": {"offset": 0, "length": 2}},
                    {"label": "expected `*/`",
                    "span": {"offset": 14, "length": 0}}
                ],
                "related": []
            }]
        }"#);
        err_eq!(parse(ws(), r#"/* com/*me*/nt *"#), r#"{
            "message": "error parsing KDL",
            "severity": "error",
            "labels": [],
            "related": [{
                "message": "unclosed comment `/*`",
                "severity": "error",
                "filename": "<test>",
                "labels": [
                    {"label": "opened here",
                    "span": {"offset": 0, "length": 2}},
                    {"label": "expected `*/`",
                    "span": {"offset": 16, "length": 0}}
                ],
                "related": []
            }]
        }"#);
        err_eq!(parse(ws(), r#"/* comment *"#), r#"{
            "message": "error parsing KDL",
            "severity": "error",
            "labels": [],
            "related": [{
                "message": "unclosed comment `/*`",
                "severity": "error",
                "filename": "<test>",
                "labels": [
                    {"label": "opened here",
                    "span": {"offset": 0, "length": 2}},
                    {"label": "expected `*/`",
                    "span": {"offset": 12, "length": 0}}
                ],
                "related": []
            }]
        }"#);
        err_eq!(parse(ws(), r#"/*/"#), r#"{
            "message": "error parsing KDL",
            "severity": "error",
            "labels": [],
            "related": [{
                "message": "unclosed comment `/*`",
                "severity": "error",
                "filename": "<test>",
                "labels": [
                    {"label": "opened here",
                    "span": {"offset": 0, "length": 2}},
                    {"label": "expected `*/`",
                    "span": {"offset": 3, "length": 0}}
                ],
                "related": []
            }]
        }"#);
        // nothing is expected for comment or whitespace
        err_eq!(parse(ws(), r#"xxx"#), r#"{
            "message": "error parsing KDL",
            "severity": "error",
            "labels": [],
            "related": [{
                "message": "found `x`, expected whitespace",
                "severity": "error",
                "filename": "<test>",
                "labels": [
                    {"label": "unexpected token",
                    "span": {"offset": 0, "length": 1}}
                ],
                "related": []
            }]
        }"#);
    }

    #[test]
    fn parse_str() {
        assert_eq!(&*parse(string(), r#""hello""#).unwrap(), "hello");
        assert_eq!(&*parse(string(), r#""""#).unwrap(), "");
        assert_eq!(&*parse(string(), r#""hel\"lo""#).unwrap(),"hel\"lo");
        assert_eq!(&*parse(string(), r#""hello\nworld!""#).unwrap(),
                   "hello\nworld!");
        assert_eq!(&*parse(string(), r#""\u{1F680}""#).unwrap(), "🚀");
    }

    #[test]
    fn parse_raw_str() {
        assert_eq!(&*parse(string(), r#"r"hello""#).unwrap(), "hello");
        assert_eq!(&*parse(string(), r##"r#"world"#"##).unwrap(), "world");
        assert_eq!(&*parse(string(), r##"r#"world"#"##).unwrap(), "world");
        assert_eq!(&*parse(string(), r####"r###"a\n"##b"###"####).unwrap(),
                   "a\\n\"##b");
    }

    #[test]
    fn parse_str_err() {
        err_eq!(parse(string(), r#""hello"#), r#"{
            "message": "error parsing KDL",
            "severity": "error",
            "labels": [],
            "related": [{
                "message": "unclosed string `\"`",
                "severity": "error",
                "filename": "<test>",
                "labels": [
                    {"label": "opened here",
                    "span": {"offset": 0, "length": 1}},
                    {"label": "expected `\"`",
                    "span": {"offset": 6, "length": 0}}
                ],
                "related": []
            }]
        }"#);
        err_eq!(parse(string(), r#""he\u{FFFFFF}llo""#), r#"{
            "message": "error parsing KDL",
            "severity": "error",
            "labels": [],
            "related": [{
                "message": "converted integer out of range for `char`",
                "severity": "error",
                "filename": "<test>",
                "labels": [
                    {"label": "invalid character code",
                    "span": {"offset": 5, "length": 8}}
                ],
                "related": []
            }]
        }"#);
        err_eq!(parse(string(), r#""he\u{1234567}llo""#), r#"{
            "message": "error parsing KDL",
            "severity": "error",
            "labels": [],
            "related": [{
                "message": "found `7`, expected `}`",
                "severity": "error",
                "filename": "<test>",
                "labels": [
                    {"label": "unexpected token",
                    "span": {"offset": 12, "length": 1}}
                ],
                "related": []
            }]
        }"#);
        err_eq!(parse(string(), r#""he\u{1gh}llo""#), r#"{
            "message": "error parsing KDL",
            "severity": "error",
            "labels": [],
            "related": [{
                "message": "found `g`, expected `}` or hexadecimal digit",
                "severity": "error",
                "filename": "<test>",
                "labels": [
                    {"label": "unexpected token",
                    "span": {"offset": 7, "length": 1}}
                ],
                "related": []
            }]
        }"#);
        err_eq!(parse(string(), r#""he\x01llo""#), r#"{
            "message": "error parsing KDL",
            "severity": "error",
            "labels": [],
            "related": [{
                "message":
                    "found `x`, expected `\"`, `/`, `\\`, `b`, `f`, `n`, `r`, `t` or `u`",
                "severity": "error",
                "filename": "<test>",
                "labels": [
                    {"label": "invalid escape char",
                    "span": {"offset": 4, "length": 1}}
                ],
                "related": []
            }]
        }"#);
        // Tests error recovery
        err_eq!(parse(string(), r#""he\u{FFFFFF}l\!lo""#), r#"{
            "message": "error parsing KDL",
            "severity": "error",
            "labels": [],
            "related": [{
                "message": "converted integer out of range for `char`",
                "severity": "error",
                "filename": "<test>",
                "labels": [
                    {"label": "invalid character code",
                    "span": {"offset": 5, "length": 8}}
                ],
                "related": []
            }, {
                "message":
                    "found `!`, expected `\"`, `/`, `\\`, `b`, `f`, `n`, `r`, `t` or `u`",
                "severity": "error",
                "filename": "<test>",
                "labels": [
                    {"label": "invalid escape char",
                    "span": {"offset": 15, "length": 1}}
                ],
                "related": []
            }]
        }"#);
    }
    #[test]
    fn parse_raw_str_err() {
        err_eq!(parse(string(), r#"r"hello"#),  r#"{
            "message": "error parsing KDL",
            "severity": "error",
            "labels": [],
            "related": [{
                "message": "unclosed raw string `r\"`",
                "severity": "error",
                "filename": "<test>",
                "labels": [
                    {"label": "opened here",
                    "span": {"offset": 0, "length": 2}},
                    {"label": "expected `\"`",
                    "span": {"offset": 7, "length": 0}}
                ],
                "related": []
            }]
        }"#);
        err_eq!(parse(string(), r###"r#"hello""###), r###"{
            "message": "error parsing KDL",
            "severity": "error",
            "labels": [],
            "related": [{
                "message": "unclosed raw string `r#\"`",
                "severity": "error",
                "filename": "<test>",
                "labels": [
                    {"label": "opened here",
                    "span": {"offset": 0, "length": 3}},
                    {"label": "expected `\"#`",
                    "span": {"offset": 9, "length": 0}}
                ],
                "related": []
            }]
        }"###);
        err_eq!(parse(string(), r####"r###"hello"####), r####"{
            "message": "error parsing KDL",
            "severity": "error",
            "labels": [],
            "related": [{
                "message": "unclosed raw string `r###\"`",
                "severity": "error",
                "filename": "<test>",
                "labels": [
                    {"label": "opened here",
                    "span": {"offset": 0, "length": 5}},
                    {"label": "expected `\"###`",
                    "span": {"offset": 10, "length": 0}}
                ],
                "related": []
            }]
        }"####);
        err_eq!(parse(string(), r####"r###"hello"#world"####), r####"{
            "message": "error parsing KDL",
            "severity": "error",
            "labels": [],
            "related": [{
                "message": "unclosed raw string `r###\"`",
                "severity": "error",
                "filename": "<test>",
                "labels": [
                    {"label": "opened here",
                    "span": {"offset": 0, "length": 5}},
                    {"label": "expected `\"###`",
                    "span": {"offset": 17, "length": 0}}
                ],
                "related": []
            }]
        }"####);
    }

    #[test]
    fn parse_ident() {
        assert_eq!(&*parse(ident(), "abcdef").unwrap(), "abcdef");
        assert_eq!(&*parse(ident(), "xx_cd$yy").unwrap(), "xx_cd$yy");
        assert_eq!(&*parse(ident(), "-").unwrap(), "-");
        assert_eq!(&*parse(ident(), "--hello").unwrap(), "--hello");
        assert_eq!(&*parse(ident(), "--hello1234").unwrap(), "--hello1234");
        assert_eq!(&*parse(ident(), "--1").unwrap(), "--1");
        assert_eq!(&*parse(ident(), "++1").unwrap(), "++1");
        assert_eq!(&*parse(ident(), "-hello").unwrap(), "-hello");
        assert_eq!(&*parse(ident(), "+hello").unwrap(), "+hello");
        assert_eq!(&*parse(ident(), "-A").unwrap(), "-A");
        assert_eq!(&*parse(ident(), "+b").unwrap(), "+b");
        assert_eq!(&*parse(ident().then_ignore(ws()), "adef   ").unwrap(),
                   "adef");
        assert_eq!(&*parse(ident().then_ignore(ws()), "a123@   ").unwrap(),
                   "a123@");
        parse(ident(), "1abc").unwrap_err();
        parse(ident(), "-1").unwrap_err();
        parse(ident(), "-1test").unwrap_err();
        parse(ident(), "+1").unwrap_err();
    }

    #[test]
    fn parse_literal() {
        assert_eq!(parse(literal(), "true").unwrap(), Literal::Bool(true));
        assert_eq!(parse(literal(), "false").unwrap(), Literal::Bool(false));
        assert_eq!(parse(literal(), "null").unwrap(), Literal::Null);
    }

    #[test]
    fn exclude_keywords() {
        parse(nodes(), "item true").unwrap();

        err_eq!(parse(nodes(), "true \"item\""), r#"{
            "message": "error parsing KDL",
            "severity": "error",
            "labels": [],
            "related": [{
                "message":
                    "found `true`, expected identifier",
                "severity": "error",
                "filename": "<test>",
                "labels": [
                    {"label": "keyword",
                    "span": {"offset": 0, "length": 4}}
                ],
                "related": []
            }]
        }"#);

        err_eq!(parse(nodes(), "item false=true"), r#"{
            "message": "error parsing KDL",
            "severity": "error",
            "labels": [],
            "related": [{
                "message":
                    "found keyword, expected identifier or string",
                "severity": "error",
                "filename": "<test>",
                "labels": [
                    {"label": "unexpected keyword",
                    "span": {"offset": 5, "length": 5}}
                ],
                "related": []
            }]
        }"#);

        err_eq!(parse(nodes(), "item 2=2"), r#"{
            "message": "error parsing KDL",
            "severity": "error",
            "labels": [],
            "related": [{
                "message": "numbers cannot be used as property names",
                "severity": "error",
                "filename": "<test>",
                "labels": [
                    {"label": "unexpected number",
                    "span": {"offset": 5, "length": 1}}
                ],
                "help": "consider enclosing in double quotes \"..\"",
                "related": []
            }]
        }"#);
    }

    #[test]
    fn parse_type() {
        assert_eq!(parse(type_name(), "(abcdef)").unwrap(),
                   TypeName::from_string("abcdef".into()));
        assert_eq!(parse(type_name(), "(xx_cd$yy)").unwrap(),
                   TypeName::from_string("xx_cd$yy".into()));
        parse(type_name(), "(1abc)").unwrap_err();
        parse(type_name(), "( abc)").unwrap_err();
        parse(type_name(), "(abc )").unwrap_err();
    }

    #[test]
    fn parse_type_err() {
        err_eq!(parse(type_name(), "(123)"), r#"{
            "message": "error parsing KDL",
            "severity": "error",
            "labels": [],
            "related": [{
                "message": "found number, expected identifier",
                "severity": "error",
                "filename": "<test>",
                "labels": [
                    {"label": "unexpected number",
                    "span": {"offset": 1, "length": 3}}
                ],
                "related": []
            }]
        }"#);

        err_eq!(parse(type_name(), "(-1)"), r#"{
            "message": "error parsing KDL",
            "severity": "error",
            "labels": [],
            "related": [{
                "message": "found number, expected identifier",
                "severity": "error",
                "filename": "<test>",
                "labels": [
                    {"label": "unexpected number",
                    "span": {"offset": 1, "length": 2}}
                ],
                "related": []
            }]
        }"#);
    }

    fn single<T, E: std::fmt::Debug>(r: Result<Vec<T>, E>) -> T {
        let mut v = r.unwrap();
        assert_eq!(v.len(), 1);
        v.remove(0)
    }

    #[test]
    fn parse_node() {
        let nval = single(parse(nodes(), "hello"));
        assert_eq!(nval.node_name.as_ref(), "hello");
        assert_eq!(nval.type_name.as_ref(), None);

        let nval = single(parse(nodes(), "\"123\""));
        assert_eq!(nval.node_name.as_ref(), "123");
        assert_eq!(nval.type_name.as_ref(), None);

        let nval = single(parse(nodes(), "(typ)other"));
        assert_eq!(nval.node_name.as_ref(), "other");
        assert_eq!(nval.type_name.as_ref().map(|x| &***x), Some("typ"));

        let nval = single(parse(nodes(), "(\"std::duration\")\"timeout\""));
        assert_eq!(nval.node_name.as_ref(), "timeout");
        assert_eq!(nval.type_name.as_ref().map(|x| &***x),
                   Some("std::duration"));

        let nval = single(parse(nodes(), "hello \"arg1\""));
        assert_eq!(nval.node_name.as_ref(), "hello");
        assert_eq!(nval.type_name.as_ref(), None);
        assert_eq!(nval.arguments.len(), 1);
        assert_eq!(nval.properties.len(), 0);
        assert_eq!(&*nval.arguments[0].literal,
                   &Literal::String("arg1".into()));

        let nval = single(parse(nodes(), "node \"true\""));
        assert_eq!(nval.node_name.as_ref(), "node");
        assert_eq!(nval.type_name.as_ref(), None);
        assert_eq!(nval.arguments.len(), 1);
        assert_eq!(nval.properties.len(), 0);
        assert_eq!(&*nval.arguments[0].literal,
                   &Literal::String("true".into()));

        let nval = single(parse(nodes(), "hello (string)\"arg1\""));
        assert_eq!(nval.node_name.as_ref(), "hello");
        assert_eq!(nval.type_name.as_ref(), None);
        assert_eq!(nval.arguments.len(), 1);
        assert_eq!(nval.properties.len(), 0);
        assert_eq!(&***nval.arguments[0].type_name.as_ref().unwrap(),
                   "string");
        assert_eq!(&*nval.arguments[0].literal,
                   &Literal::String("arg1".into()));

        let nval = single(parse(nodes(), "hello key=(string)\"arg1\""));
        assert_eq!(nval.node_name.as_ref(), "hello");
        assert_eq!(nval.type_name.as_ref(), None);
        assert_eq!(nval.arguments.len(), 0);
        assert_eq!(nval.properties.len(), 1);
        assert_eq!(&***nval.properties.get("key").unwrap()
                   .type_name.as_ref().unwrap(),
                   "string");
        assert_eq!(&*nval.properties.get("key").unwrap().literal,
                   &Literal::String("arg1".into()));

        let nval = single(parse(nodes(), "hello key=\"arg1\""));
        assert_eq!(nval.node_name.as_ref(), "hello");
        assert_eq!(nval.type_name.as_ref(), None);
        assert_eq!(nval.arguments.len(), 0);
        assert_eq!(nval.properties.len(), 1);
        assert_eq!(&*nval.properties.get("key").unwrap().literal,
                   &Literal::String("arg1".into()));

        let nval = single(parse(nodes(), "parent {\nchild\n}"));
        assert_eq!(nval.node_name.as_ref(), "parent");
        assert_eq!(nval.children().len(), 1);
        assert_eq!(nval.children.as_ref().unwrap()[0].node_name.as_ref(),
                   "child");

        let nval = single(parse(nodes(), "parent {\nchild1\nchild2\n}"));
        assert_eq!(nval.node_name.as_ref(), "parent");
        assert_eq!(nval.children().len(), 2);
        assert_eq!(nval.children.as_ref().unwrap()[0].node_name.as_ref(),
                   "child1");
        assert_eq!(nval.children.as_ref().unwrap()[1].node_name.as_ref(),
                   "child2");

        let nval = single(parse(nodes(), "parent{\nchild3\n}"));
        assert_eq!(nval.node_name.as_ref(), "parent");
        assert_eq!(nval.children().len(), 1);
        assert_eq!(nval.children.as_ref().unwrap()[0].node_name.as_ref(),
                   "child3");

        let nval = single(parse(nodes(), "parent \"x\"=1 {\nchild4\n}"));
        assert_eq!(nval.node_name.as_ref(), "parent");
        assert_eq!(nval.properties.len(), 1);
        assert_eq!(nval.children().len(), 1);
        assert_eq!(nval.children.as_ref().unwrap()[0].node_name.as_ref(),
                   "child4");

        let nval = single(parse(nodes(), "parent \"x\" {\nchild4\n}"));
        assert_eq!(nval.node_name.as_ref(), "parent");
        assert_eq!(nval.arguments.len(), 1);
        assert_eq!(nval.children().len(), 1);
        assert_eq!(nval.children.as_ref().unwrap()[0].node_name.as_ref(),
                   "child4");

        let nval = single(parse(nodes(), "parent \"x\"{\nchild5\n}"));
        assert_eq!(nval.node_name.as_ref(), "parent");
        assert_eq!(nval.arguments.len(), 1);
        assert_eq!(nval.children().len(), 1);
        assert_eq!(nval.children.as_ref().unwrap()[0].node_name.as_ref(),
                   "child5");

        let nval = single(parse(nodes(), "hello /-\"skip_arg\" \"arg2\""));
        assert_eq!(nval.node_name.as_ref(), "hello");
        assert_eq!(nval.type_name.as_ref(), None);
        assert_eq!(nval.arguments.len(), 1);
        assert_eq!(nval.properties.len(), 0);
        assert_eq!(&*nval.arguments[0].literal,
                   &Literal::String("arg2".into()));

        let nval = single(parse(nodes(), "hello /- \"skip_arg\" \"arg2\""));
        assert_eq!(nval.node_name.as_ref(), "hello");
        assert_eq!(nval.type_name.as_ref(), None);
        assert_eq!(nval.arguments.len(), 1);
        assert_eq!(nval.properties.len(), 0);
        assert_eq!(&*nval.arguments[0].literal,
                   &Literal::String("arg2".into()));

        let nval = single(parse(nodes(), "hello prop1=\"1\" /-prop1=\"2\""));
        assert_eq!(nval.node_name.as_ref(), "hello");
        assert_eq!(nval.type_name.as_ref(), None);
        assert_eq!(nval.arguments.len(), 0);
        assert_eq!(nval.properties.len(), 1);
        assert_eq!(&*nval.properties.get("prop1").unwrap().literal,
                   &Literal::String("1".into()));

        let nval = single(parse(nodes(), "parent /-{\nchild\n}"));
        assert_eq!(nval.node_name.as_ref(), "parent");
        assert_eq!(nval.children().len(), 0);
    }

    #[test]
    fn parse_node_whitespace() {
        let nval = single(parse(nodes(), "hello  {   }"));
        assert_eq!(nval.node_name.as_ref(), "hello");
        assert_eq!(nval.type_name.as_ref(), None);

        let nval = single(parse(nodes(), "hello  {   }  "));
        assert_eq!(nval.node_name.as_ref(), "hello");
        assert_eq!(nval.type_name.as_ref(), None);

        let nval = single(parse(nodes(), "hello "));
        assert_eq!(nval.node_name.as_ref(), "hello");
        assert_eq!(nval.type_name.as_ref(), None);

        let nval = single(parse(nodes(), "hello   "));
        assert_eq!(nval.node_name.as_ref(), "hello");
        assert_eq!(nval.type_name.as_ref(), None);
    }

    #[test]
    fn parse_node_err() {
        err_eq!(parse(nodes(), "hello{"), r#"{
            "message": "error parsing KDL",
            "severity": "error",
            "labels": [],
            "related": [{
                "message": "unclosed curly braces `{`",
                "severity": "error",
                "filename": "<test>",
                "labels": [
                    {"label": "opened here",
                    "span": {"offset": 5, "length": 1}},
                    {"label": "expected `}`",
                    "span": {"offset": 6, "length": 0}}
                ],
                "related": []
            }]
        }"#);
        err_eq!(parse(nodes(), "hello world"), r#"{
            "message": "error parsing KDL",
            "severity": "error",
            "labels": [],
            "related": [{
                "message": "identifiers cannot be used as arguments",
                "severity": "error",
                "filename": "<test>",
                "labels": [
                    {"label": "unexpected identifier",
                    "span": {"offset": 6, "length": 5}}
                ],
                "help": "consider enclosing in double quotes \"..\"",
                "related": []
            }]
        }"#);

        err_eq!(parse(nodes(), "hello world {"), r#"{
            "message": "error parsing KDL",
            "severity": "error",
            "labels": [],
            "related": [{
                "message": "identifiers cannot be used as arguments",
                "severity": "error",
                "filename": "<test>",
                "labels": [
                    {"label": "unexpected identifier",
                    "span": {"offset": 6, "length": 5}}
                ],
                "help": "consider enclosing in double quotes \"..\"",
                "related": []
            }, {
                "message": "unclosed curly braces `{`",
                "severity": "error",
                "filename": "<test>",
                "labels": [
                    {"label": "opened here",
                    "span": {"offset": 12, "length": 1}},
                    {"label": "expected `}`",
                    "span": {"offset": 13, "length": 0}}
                ],
                "related": []
            }]
        }"#);

        err_eq!(parse(nodes(), "1 + 2"), r#"{
            "message": "error parsing KDL",
            "severity": "error",
            "labels": [],
            "related": [{
                "message": "found number, expected identifier",
                "severity": "error",
                "filename": "<test>",
                "labels": [
                    {"label": "unexpected number",
                    "span": {"offset": 0, "length": 1}}
                ],
                "related": []
            }]
        }"#);

        err_eq!(parse(nodes(), "-1 +2"), r#"{
            "message": "error parsing KDL",
            "severity": "error",
            "labels": [],
            "related": [{
                "message": "found number, expected identifier",
                "severity": "error",
                "filename": "<test>",
                "labels": [
                    {"label": "unexpected number",
                    "span": {"offset": 0, "length": 2}}
                ],
                "related": []
            }]
        }"#);

    }

    #[test]
    fn parse_nodes() {
        let nval = parse(nodes(), "parent {\n/-  child\n}").unwrap();
        assert_eq!(nval.len(), 1);
        assert_eq!(nval[0].node_name.as_ref(), "parent");
        assert_eq!(nval[0].children().len(), 0);

        let nval = parse(nodes(), "/-parent {\n  child\n}\nsecond").unwrap();
        assert_eq!(nval.len(), 1);
        assert_eq!(nval[0].node_name.as_ref(), "second");
        assert_eq!(nval[0].children().len(), 0);

    }

    #[test]
    fn parse_number() {
        assert_eq!(parse(number(), "12").unwrap(),
                   Literal::Int(Integer(Radix::Dec, "12".into())));
        assert_eq!(parse(number(), "012").unwrap(),
                   Literal::Int(Integer(Radix::Dec, "012".into())));
        assert_eq!(parse(number(), "0").unwrap(),
                   Literal::Int(Integer(Radix::Dec, "0".into())));
        assert_eq!(parse(number(), "-012").unwrap(),
                   Literal::Int(Integer(Radix::Dec, "-012".into())));
        assert_eq!(parse(number(), "+0").unwrap(),
                   Literal::Int(Integer(Radix::Dec, "+0".into())));
        assert_eq!(parse(number(), "123_555").unwrap(),
                   Literal::Int(Integer(Radix::Dec, "123555".into())));
        assert_eq!(parse(number(), "123.555").unwrap(),
                   Literal::Decimal(Decimal("123.555".into())));
        assert_eq!(parse(number(), "+1_23.5_55E-17").unwrap(),
                   Literal::Decimal(Decimal("+123.555E-17".into())));
        assert_eq!(parse(number(), "123e+555").unwrap(),
                   Literal::Decimal(Decimal("123e+555".into())));
    }

    #[test]
    fn parse_radix_number() {
        assert_eq!(parse(number(), "0x12").unwrap(),
                   Literal::Int(Integer(Radix::Hex, "12".into())));
        assert_eq!(parse(number(), "0xab_12").unwrap(),
                   Literal::Int(Integer(Radix::Hex, "ab12".into())));
        assert_eq!(parse(number(), "-0xab_12").unwrap(),
                   Literal::Int(Integer(Radix::Hex, "-ab12".into())));
        assert_eq!(parse(number(), "0o17").unwrap(),
                   Literal::Int(Integer(Radix::Oct, "17".into())));
        assert_eq!(parse(number(), "+0o17").unwrap(),
                   Literal::Int(Integer(Radix::Oct, "+17".into())));
        assert_eq!(parse(number(), "0b1010_101").unwrap(),
                   Literal::Int(Integer(Radix::Bin, "1010101".into())));
    }

    #[test]
    fn parse_dashes() {
        let nval = parse(nodes(), "-").unwrap();
        assert_eq!(nval.len(), 1);
        assert_eq!(nval[0].node_name.as_ref(), "-");
        assert_eq!(nval[0].children().len(), 0);

        let nval = parse(nodes(), "--").unwrap();
        assert_eq!(nval.len(), 1);
        assert_eq!(nval[0].node_name.as_ref(), "--");
        assert_eq!(nval[0].children().len(), 0);

        let nval = parse(nodes(), "--1").unwrap();
        assert_eq!(nval.len(), 1);
        assert_eq!(nval[0].node_name.as_ref(), "--1");
        assert_eq!(nval[0].children().len(), 0);

        let nval = parse(nodes(), "-\n-").unwrap();
        assert_eq!(nval.len(), 2);
        assert_eq!(nval[0].node_name.as_ref(), "-");
        assert_eq!(nval[0].children().len(), 0);
        assert_eq!(nval[1].node_name.as_ref(), "-");
        assert_eq!(nval[1].children().len(), 0);

        let nval = parse(nodes(), "node -1 --x=2").unwrap();
        assert_eq!(nval.len(), 1);
        assert_eq!(nval[0].arguments.len(), 1);
        assert_eq!(nval[0].properties.len(), 1);
        assert_eq!(&*nval[0].arguments[0].literal,
                   &Literal::Int(Integer(Radix::Dec, "-1".into())));
        assert_eq!(&*nval[0].properties.get("--x").unwrap().literal,
                   &Literal::Int(Integer(Radix::Dec, "2".into())));
    }
}