organic/src/parser/nom_context.rs

use std::cell::RefCell;
use std::rc::Rc;

use nom::branch::alt;
use nom::error::VerboseError;
use nom::IResult;
use nom::Parser;

pub type MatcherInner = Rc<RefCell<dyn FnMut(&str) -> IResult<&str, &str, VerboseError<&str>>>>;

struct MatcherRef(MatcherInner);

impl MatcherRef {
    pub fn new(func: MatcherInner) -> Self {
        Self(func)
    }
}

// type MatcherRef = Rc<RefCell<dyn FnMut(&str) -> IResult<&str, &str, VerboseError<&str>>>>;

enum ChainBehavior {
    AndParent(Option<MatcherRef>),
    IgnoreParent(Option<MatcherRef>),
}

pub struct NomContext<'a> {
    pub parent: Option<&'a Self>,
    fail_matcher: ChainBehavior,
    /// You can't have nested bolds or links in org-mode
    pub can_match_bold: bool,
    pub can_match_link: bool,
}

impl<'a> NomContext<'a> {
    pub fn new(fail_matcher: MatcherInner) -> Self {
        NomContext {
            parent: None,
            fail_matcher: ChainBehavior::IgnoreParent(Some(MatcherRef::new(fail_matcher))),
            can_match_bold: true,
            can_match_link: true,
        }
    }

    pub fn with_additional_fail_matcher(&self, other: MatcherInner) -> NomContext {
        NomContext {
            parent: Some(&self),
            fail_matcher: ChainBehavior::AndParent(Some(MatcherRef::new(other))),
            can_match_bold: self.can_match_bold,
            can_match_link: self.can_match_link,
        }
    }
}

impl Parser<&str, &str, VerboseError<&str>> for MatcherRef {
    fn parse(&mut self, i: &str) -> IResult<&str, &str, VerboseError<&str>> {
        (&mut *self.0.borrow_mut())(i)
    }
}