duster/src/renderer/context_element.rs
2020-05-10 21:11:49 -04:00

67 lines
1.9 KiB
Rust

use crate::parser::Filter;
use crate::renderer::errors::RenderError;
use crate::renderer::errors::WalkError;
use std::any::Any;
use std::fmt::Debug;
pub trait ContextElement:
Debug + Walkable + Renderable + Loopable + CloneIntoBoxedContextElement + CompareContextElement
{
}
pub trait Walkable {
fn walk(&self, segment: &str) -> Result<&dyn ContextElement, WalkError>;
}
pub trait Renderable {
fn render(&self, filters: &Vec<Filter>) -> Result<String, RenderError>;
}
pub trait Loopable {
/// Return the elements for a Dust section
///
/// Sections in dust are accomplished with the {#path} syntax. A
/// section has a truthiness check performed on it. If that
/// truthiness check fails, then it will render the
/// else-block. Otherwise if its a scalar value it will render
/// once with the context being the element at that path. Finally,
/// if its an array-like value then it will render n-times, once
/// for each element of the array.
fn get_loop_elements(&self) -> Vec<&dyn ContextElement>;
}
pub trait CompareContextElement {
fn to_any(&self) -> &dyn Any;
fn equals(&self, other: &dyn ContextElement) -> bool;
}
pub trait CloneIntoBoxedContextElement {
fn clone_to_box(&self) -> Box<dyn ContextElement>;
}
impl<C: 'static + ContextElement + Clone> CloneIntoBoxedContextElement for C {
fn clone_to_box(&self) -> Box<dyn ContextElement> {
Box::new(self.clone())
}
}
impl<C: 'static + ContextElement + PartialEq> CompareContextElement for C {
fn to_any(&self) -> &dyn Any {
self
}
fn equals(&self, other: &dyn ContextElement) -> bool {
other
.to_any()
.downcast_ref::<Self>()
.map_or(false, |a| self == a)
}
}
impl<'a, 'b> PartialEq<&'b dyn ContextElement> for &'a dyn ContextElement {
fn eq(&self, other: &&'b dyn ContextElement) -> bool {
self.equals(*other)
}
}