1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130

use nom::{character::complete::*, multi::many1_count, IResult};
use nom_supreme::{
    error::ErrorTree,
    final_parser::{final_parser, Location},
};
use std::fmt;

pub mod headings;
pub mod paragraphs;
pub mod thematic_breaks;

pub use headings::{atx_heading, ATXHeading};
pub use paragraphs::{paragraph, Paragraph};
pub use thematic_breaks::{thematic_break, ThematicBreak};

// TODO: maybe get rid of Copy/Clone here?
// it's required by fold_many0
#[derive(Debug, PartialEq, Eq, Copy, Clone)]
pub enum MdxAst<'a> {
    ATXHeading(ATXHeading<'a>),
    ThematicBreak(ThematicBreak),
    Paragraph(Paragraph<'a>),
}
impl<'a> fmt::Display for MdxAst<'a> {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        match self {
            MdxAst::ATXHeading(atx) => write!(f, "{}", atx),
            MdxAst::ThematicBreak(brk) => write!(f, "{}", brk),
            MdxAst::Paragraph(para) => write!(f, "{}", para),
        }
        // Use `self.number` to refer to each positional data point.
    }
}

pub fn mdx_elements(input: &str) -> Result<Vec<MdxAst>, ErrorTree<Location>> {
    final_parser(mdx_elements_internal)(input)
}
fn mdx_elements_internal(input: &str) -> IResult<&str, Vec<MdxAst>, ErrorTree<&str>> {
    let (input, _) = multispace0(input)?;
    let (input, result) = nom::multi::separated_list1(many1_count(newline), mdx_ast)(input)?;
    let (input, _) = multispace0(input)?;
    let (input, _) = nom::combinator::eof(input)?;
    Ok((input, result))
}

fn mdx_ast(input: &str) -> IResult<&str, MdxAst, ErrorTree<&str>> {
    nom::branch::alt((ast_atx_heading, ast_thematic_break, ast_paragraph))(input)
}

/// We have to wrap the structs to fit in the MdxAst
fn ast_atx_heading(input: &str) -> IResult<&str, MdxAst, ErrorTree<&str>> {
    let (input, atx) = atx_heading(input)?;
    Ok((input, MdxAst::ATXHeading(atx)))
}

fn ast_thematic_break(input: &str) -> IResult<&str, MdxAst, ErrorTree<&str>> {
    let (input, thematic_break) = thematic_break(input)?;
    Ok((input, MdxAst::ThematicBreak(thematic_break)))
}

fn ast_paragraph(input: &str) -> IResult<&str, MdxAst, ErrorTree<&str>> {
    let (input, paragraph) = paragraph(input)?;
    Ok((input, MdxAst::Paragraph(paragraph)))
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn parse_heading() {
        assert_eq!(
            mdx_ast("# boop").unwrap(),
            (
                "",
                MdxAst::ATXHeading(ATXHeading {
                    level: 1,
                    value: "boop"
                }),
            )
        );
    }
    #[test]
    fn parse_thematic_break() {
        assert_eq!(
            mdx_ast("---").unwrap(),
            (
                "",
                MdxAst::ThematicBreak(ThematicBreak {
                    char_count: 3,
                    break_char: '-'
                }),
            )
        );
    }
}

#[cfg(test)]
mod tests_2 {
    use super::*;

    #[test]
    // this input string is sloppy for a reason.
    // that reason is to ensure the parser handles sloppy
    // input when it comes to whitespace
    fn parse_headings() {
        assert_eq!(
            mdx_elements(
                "
# boop


## boop

"
            )
            .unwrap(),
            vec![
                MdxAst::ATXHeading(ATXHeading {
                    level: 1,
                    value: "boop"
                }),
                MdxAst::ATXHeading(ATXHeading {
                    level: 2,
                    value: "boop"
                }),
            ]
        );
    }
}