typst/src/model/show.rs

114 lines
2.7 KiB
Rust

use std::fmt::{self, Debug, Formatter, Write};
use std::hash::Hash;
use std::sync::Arc;
use super::{Content, NodeId, StyleChain};
use crate::diag::TypResult;
use crate::eval::Dict;
use crate::util::Prehashed;
use crate::Context;
/// A node that can be realized given some styles.
pub trait Show: 'static {
/// Encode this node into a dictionary.
fn encode(&self) -> Dict;
/// The base recipe for this node that is executed if there is no
/// user-defined show rule.
fn realize(&self, ctx: &mut Context, styles: StyleChain) -> TypResult<Content>;
/// Finalize this node given the realization of a base or user recipe. Use
/// this for effects that should work even in the face of a user-defined
/// show rule, for example:
/// - Application of general settable properties
/// - Attaching things like semantics to a heading
///
/// Defaults to just the realized content.
#[allow(unused_variables)]
fn finalize(
&self,
ctx: &mut Context,
styles: StyleChain,
realized: Content,
) -> TypResult<Content> {
Ok(realized)
}
/// Convert to a packed show node.
fn pack(self) -> ShowNode
where
Self: Debug + Hash + Sized + Sync + Send + 'static,
{
ShowNode::new(self)
}
}
/// A type-erased showable node with a precomputed hash.
#[derive(Clone, Hash)]
pub struct ShowNode(Arc<Prehashed<dyn Bounds>>);
impl ShowNode {
/// Pack any showable node.
pub fn new<T>(node: T) -> Self
where
T: Show + Debug + Hash + Sync + Send + 'static,
{
Self(Arc::new(Prehashed::new(node)))
}
/// The id of this node.
pub fn id(&self) -> NodeId {
(**self.0).node_id()
}
}
impl Show for ShowNode {
fn encode(&self) -> Dict {
self.0.encode()
}
fn realize(&self, ctx: &mut Context, styles: StyleChain) -> TypResult<Content> {
self.0.realize(ctx, styles)
}
fn finalize(
&self,
ctx: &mut Context,
styles: StyleChain,
realized: Content,
) -> TypResult<Content> {
self.0.finalize(ctx, styles, realized)
}
fn pack(self) -> ShowNode {
self
}
}
impl Debug for ShowNode {
fn fmt(&self, f: &mut Formatter) -> fmt::Result {
f.write_str("Show(")?;
self.0.fmt(f)?;
f.write_char(')')
}
}
impl PartialEq for ShowNode {
fn eq(&self, other: &Self) -> bool {
self.0.eq(&other.0)
}
}
trait Bounds: Show + Debug + Sync + Send + 'static {
fn node_id(&self) -> NodeId;
}
impl<T> Bounds for T
where
T: Show + Debug + Hash + Sync + Send + 'static,
{
fn node_id(&self) -> NodeId {
NodeId::of::<Self>()
}
}