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//This module defines the domain specific language.
use std::{borrow::Cow, rc::Rc};
use super::data::{Location, Mood, Speaker};
use higher::Functor;
use higher_free_macro::free;
use std::convert::identity;
#[derive(Clone)]
pub enum SausageRoll<'a, 's, A> {
SayDialogueLine {
speaker: Speaker,
text: Cow<'s, str>, //In a real project I would just make this a String. Here it's a reference to show off lifetime support.
mood: Mood,
next: A,
},
GivePlayerOptions {
options: Vec<&'s str>,
next: Rc<dyn Fn(usize) -> A + 'a>, //let's just assume that the interpreter validates input.
},
PresentLocation {
location: Location,
next: A,
},
Exposition {
text: &'s str,
next: A,
},
}
impl<'a, 's, A: 'a> Functor<'a, A> for SausageRoll<'a, 's, A> {
type Target<T> = SausageRoll<'a, 's, T>;
fn fmap<B, F>(self, f: F) -> Self::Target<B>
where
F: Fn(A) -> B + 'a,
{
match self {
SausageRoll::SayDialogueLine {
speaker,
text,
mood,
next,
} => SausageRoll::SayDialogueLine {
speaker,
text,
mood,
next: f(next),
},
SausageRoll::GivePlayerOptions { options, next } => SausageRoll::GivePlayerOptions {
options,
next: Rc::new(move |x| f(next(x))),
},
SausageRoll::PresentLocation { location, next } => SausageRoll::PresentLocation {
location,
next: f(next),
},
SausageRoll::Exposition { text, next } => SausageRoll::Exposition {
text,
next: f(next),
},
}
}
}
free!(<'a>, pub FreeSausageRoll<'a,'s,A>, SausageRoll<'a, 's, FreeSausageRoll<'a,'s,A>>);
pub fn say_dialogue_line<'a, 's: 'a>(
speaker: Speaker,
text: Cow<'s, str>,
mood: Mood,
) -> FreeSausageRoll<'a, 's, ()> {
FreeSausageRoll::lift_f(SausageRoll::SayDialogueLine {
speaker,
text,
mood,
next: (),
})
}
pub fn give_player_options<'a, 's: 'a>(options: Vec<&'s str>) -> FreeSausageRoll<'a, 's, usize> {
FreeSausageRoll::lift_f(SausageRoll::GivePlayerOptions {
options,
next: Rc::new(identity),
})
}
pub fn present_location<'a, 's: 'a>(location: Location) -> FreeSausageRoll<'a, 's, ()> {
FreeSausageRoll::lift_f(SausageRoll::PresentLocation { location, next: () })
}
pub fn exposition<'a, 's: 'a>(text: &'s str) -> FreeSausageRoll<'a, 's, ()> {
FreeSausageRoll::lift_f(SausageRoll::Exposition { text, next: () })
}
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