organic/src/parser/text_markup.rs

use nom::branch::alt;
use nom::bytes::complete::tag;
use nom::combinator::peek;
use nom::combinator::verify;
use nom::multi::many_till;
use nom::sequence::terminated;

use super::Context;
use crate::error::CustomError;
use crate::error::MyError;
use crate::error::Res;
use crate::parser::exiting::ExitClass;
use crate::parser::object_parser::standard_set_object;
use crate::parser::parser_context::ContextElement;
use crate::parser::parser_context::ExitMatcherNode;
use crate::parser::parser_with_context::parser_with_context;
use crate::parser::util::exit_matcher_parser;
use crate::parser::util::get_consumed;
use crate::parser::util::get_one_before;
use crate::parser::TextMarkup;

#[tracing::instrument(ret, level = "debug")]
pub fn text_markup<'r, 's>(
    context: Context<'r, 's>,
    input: &'s str,
) -> Res<&'s str, TextMarkup<'s>> {
    let (remaining, _) = pre(context, input)?;
    let (remaining, open) = marker(remaining)?;
    let text_markup_end_specialized = text_markup_end(open);
    let parser_context =
        context.with_additional_node(ContextElement::ExitMatcherNode(ExitMatcherNode {
            class: ExitClass::Beta,
            exit_matcher: &text_markup_end_specialized,
        }));

    let (remaining, (children, _exit_contents)) = verify(
        many_till(
            parser_with_context!(standard_set_object)(&parser_context),
            parser_with_context!(exit_matcher_parser)(&parser_context),
        ),
        |(children, _exit_contents)| !children.is_empty(),
    )(remaining)?;

    // TODO: Sometimes its plain text, not objects
    let (remaining, close) = text_markup_end_specialized(context, remaining)?;

    let source = get_consumed(input, remaining);

    Ok((remaining, TextMarkup { source, children }))
}

#[tracing::instrument(ret, level = "debug")]
pub fn pre<'r, 's>(context: Context<'r, 's>, input: &'s str) -> Res<&'s str, ()> {
    let document_root = context.get_document_root().unwrap();
    let preceding_character = get_one_before(document_root, input)
        .map(|slice| slice.chars().next())
        .flatten();
    match preceding_character {
        // If None, we are at the start of the file which is technically the beginning of a line.
        None | Some('\r') | Some('\n') | Some(' ') | Some('\t') | Some('-') | Some('(')
        | Some('{') | Some('\'') | Some('"') => {}
        Some(_) => {
            // Not at start of line, cannot be a heading
            return Err(nom::Err::Error(CustomError::MyError(MyError(
                "Not a valid pre character for text markup.",
            ))));
        }
    };
    Ok((input, ()))
}

#[tracing::instrument(ret, level = "debug")]
pub fn post<'r, 's>(context: Context<'r, 's>, input: &'s str) -> Res<&'s str, ()> {
    let document_root = context.get_document_root().unwrap();
    let preceding_character = get_one_before(document_root, input)
        .map(|slice| slice.chars().next())
        .flatten();
    match preceding_character {
        // If None, we are at the start of the file which is technically the beginning of a line.
        None | Some('\r') | Some('\n') | Some(' ') | Some('\t') | Some('-') | Some('(')
        | Some('{') | Some('\'') | Some('"') => {}
        Some(_) => {
            // Not at start of line, cannot be a heading
            return Err(nom::Err::Error(CustomError::MyError(MyError(
                "Not a valid pre character for text markup.",
            ))));
        }
    };
    Ok((input, ()))
}

#[tracing::instrument(ret, level = "debug")]
pub fn marker(input: &str) -> Res<&str, &str> {
    alt((tag("*"), tag("/"), tag("_"), tag("="), tag("~"), tag("+")))(input)
}

fn text_markup_end(
    marker_symbol: &str,
) -> impl for<'r, 's> Fn(Context<'r, 's>, &'s str) -> Res<&'s str, &'s str> {
    let marker_symbol = marker_symbol.to_owned();
    move |context: Context, input: &str| _text_markup_end(context, input, marker_symbol.as_str())
}

#[tracing::instrument(ret, level = "debug")]
fn _text_markup_end<'r, 's, 'x>(
    context: Context<'r, 's>,
    input: &'s str,
    marker_symbol: &'x str,
) -> Res<&'s str, &'s str> {
    let (remaining, _marker) = terminated(
        tag(marker_symbol),
        peek(parser_with_context!(post)(context)),
    )(input)?;
    let source = get_consumed(input, remaining);
    Ok((remaining, source))
}