organic/src/parser/nom_context.rs

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

use nom::branch::alt;
use nom::combinator::not;
use nom::error::VerboseError;
use nom::IResult;
use nom::Parser;

pub struct TestContext<T> {
    head: ContextReference<T>,
}

type ContextReference<T> = Option<Box<ContextLayer<T>>>;

struct ContextLayer<T> {
    data: T,
    parent: ContextReference<T>,
}

struct ContextData {
    fail_matcher: ChainBehavior,
}

impl TestContext<ContextData> {
    pub fn new() -> Self {
        TestContext { head: None }
    }

    pub fn with_additional_fail_matcher(
        &self,
        new_matcher: MatcherRef,
    ) -> TestContext<ContextData> {
        TestContext {
            head: Some(Box::new(ContextLayer {
                data: ContextData {
                    fail_matcher: ChainBehavior::AndParent(Some(new_matcher)),
                },
                parent: self.head, // TODO FIX THIS
            })),
        }
    }
}

/////
///// OLD
/////

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

struct FailChecker<'r>(&'r NomContext<'r>);

impl<'r> FailChecker<'r> {
    fn new(func: &'r NomContext<'r>) -> Self {
        Self(func)
    }
}

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

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

impl<'r> NomContext<'r> {
    pub fn new(fail_matcher: MatcherRef) -> Self {
        NomContext {
            parent: None,
            fail_matcher: ChainBehavior::IgnoreParent(Some(fail_matcher)),
            match_bold_allowed: true,
            match_link_allowed: true,
        }
    }

    pub fn with_additional_fail_matcher(&self, other: MatcherRef) -> NomContext {
        NomContext {
            parent: Some(&self),
            fail_matcher: ChainBehavior::AndParent(Some(other)),
            match_bold_allowed: self.match_bold_allowed,
            match_link_allowed: self.match_link_allowed,
        }
    }

    pub fn without_bold(&self, other: MatcherRef) -> NomContext {
        NomContext {
            parent: Some(&self),
            fail_matcher: ChainBehavior::AndParent(Some(other)),
            match_bold_allowed: false,
            match_link_allowed: self.match_link_allowed,
        }
    }

    pub fn not_matching_fail<'s>(&self, i: &'s str) -> IResult<&'s str, (), VerboseError<&'s str>> {
        not(FailChecker::new(self))(i)
    }

    pub fn can_match_bold(&self) -> bool {
        self.match_bold_allowed
    }

    pub fn can_match_link(&self) -> bool {
        self.match_link_allowed
    }
}

impl<'r, 's> Parser<&'s str, &'s str, VerboseError<&'s str>> for FailChecker<'r> {
    fn parse(&mut self, i: &'s str) -> IResult<&'s str, &'s str, VerboseError<&'s str>> {
        let fail_func = match &self.0.fail_matcher {
            ChainBehavior::AndParent(inner) => inner,
            ChainBehavior::IgnoreParent(inner) => inner,
        };
        if let Some(inner) = fail_func {
            let parsed = (&mut *inner.borrow_mut())(i);
            if parsed.is_ok() {
                return parsed;
            }
        }
        match (self.0.parent, &self.0.fail_matcher) {
            (None, _) | (_, ChainBehavior::IgnoreParent(_)) => Err(nom::Err::Error(
                nom::error::make_error(i, nom::error::ErrorKind::Alt),
            )),
            (Some(parent), ChainBehavior::AndParent(_)) => {
                let mut parent_fail_checker = FailChecker::new(parent);
                parent_fail_checker.parse(i)
            }
        }
    }
}