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|
//! Execution of syntax trees.
mod context;
mod state;
pub use context::*;
pub use state::*;
use std::rc::Rc;
use crate::diag::Pass;
use crate::env::Env;
use crate::eval::{ExprMap, TemplateAny, TemplateNode, Value, ValueTemplate};
use crate::geom::Spec;
use crate::layout::{self, Expansion, NodeSpacing, NodeStack};
use crate::pretty::pretty;
use crate::syntax::*;
/// Execute a syntax tree to produce a layout tree.
///
/// The `map` shall be an expression map computed for this tree with
/// [`eval`](crate::eval::eval). Note that `tree` must be the _exact_ same tree
/// as used for evaluation (no cloned version), because the expression map
/// depends on the pointers being stable.
///
/// The `state` is the base state that may be updated over the course of
/// execution.
pub fn exec(
env: &mut Env,
tree: &Tree,
map: &ExprMap,
state: State,
) -> Pass<layout::Tree> {
let mut ctx = ExecContext::new(env, state);
ctx.start_page_group(Softness::Hard);
tree.exec_with(&mut ctx, &map);
ctx.end_page_group(|s| s == Softness::Hard);
ctx.finish()
}
/// Execute a node.
///
/// This manipulates active styling and document state and produces layout
/// nodes. Because syntax nodes and layout nodes do not correspond one-to-one,
/// constructed layout nodes are pushed into the context instead of returned.
/// The context takes care of reshaping the nodes into the correct tree
/// structure.
pub trait Exec {
/// Execute the node.
fn exec(&self, ctx: &mut ExecContext);
}
/// Execute a node with an expression map that applies to it.
pub trait ExecWith {
/// Execute the node.
fn exec_with(&self, ctx: &mut ExecContext, map: &ExprMap);
}
impl ExecWith for Tree {
fn exec_with(&self, ctx: &mut ExecContext, map: &ExprMap) {
for node in self {
node.exec_with(ctx, map);
}
}
}
impl ExecWith for Node {
fn exec_with(&self, ctx: &mut ExecContext, map: &ExprMap) {
match self {
Node::Text(text) => ctx.push_text(text),
Node::Space => ctx.push_space(),
Node::Linebreak => ctx.apply_linebreak(),
Node::Parbreak => ctx.apply_parbreak(),
Node::Strong => ctx.state.font.strong ^= true,
Node::Emph => ctx.state.font.emph ^= true,
Node::Heading(heading) => heading.exec_with(ctx, map),
Node::Raw(raw) => raw.exec(ctx),
Node::Expr(expr) => map[&(expr as *const _)].exec(ctx),
}
}
}
impl ExecWith for NodeHeading {
fn exec_with(&self, ctx: &mut ExecContext, map: &ExprMap) {
let prev = ctx.state.clone();
let upscale = 1.5 - 0.1 * self.level as f64;
ctx.state.font.scale *= upscale;
ctx.state.font.strong = true;
self.contents.exec_with(ctx, map);
ctx.apply_parbreak();
ctx.state = prev;
}
}
impl Exec for NodeRaw {
fn exec(&self, ctx: &mut ExecContext) {
let prev = Rc::clone(&ctx.state.font.families);
let families = ctx.state.font.families_mut();
families.list.insert(0, "monospace".to_string());
families.flatten();
let em = ctx.state.font.font_size();
let line_spacing = ctx.state.par.line_spacing.resolve(em);
let mut children = vec![];
for line in &self.lines {
children.push(layout::Node::Text(ctx.make_text_node(line.clone())));
children.push(layout::Node::Spacing(NodeSpacing {
amount: line_spacing,
softness: Softness::Hard,
}));
}
if self.block {
ctx.apply_parbreak();
}
ctx.push(NodeStack {
dirs: ctx.state.dirs,
align: ctx.state.align,
expand: Spec::uniform(Expansion::Fit),
children,
});
if self.block {
ctx.apply_parbreak();
}
ctx.state.font.families = prev;
}
}
impl Exec for Value {
fn exec(&self, ctx: &mut ExecContext) {
match self {
Value::None => {}
Value::Str(s) => ctx.push_text(s),
Value::Template(template) => template.exec(ctx),
other => ctx.push_text(pretty(other)),
}
}
}
impl Exec for ValueTemplate {
fn exec(&self, ctx: &mut ExecContext) {
for part in self {
part.exec(ctx);
}
}
}
impl Exec for TemplateNode {
fn exec(&self, ctx: &mut ExecContext) {
match self {
Self::Tree { tree, map } => tree.exec_with(ctx, &map),
Self::Any(any) => any.exec(ctx),
}
}
}
impl Exec for TemplateAny {
fn exec(&self, ctx: &mut ExecContext) {
self(ctx);
}
}
|
