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|
//! Dynamic typesetting functions.
use std::collections::HashMap;
use std::fmt::{self, Debug, Formatter};
use self::prelude::*;
#[macro_use]
mod macros;
/// Useful imports for creating your own functions.
pub mod prelude {
pub use super::{Scope, Parse, Command, Commands};
pub use crate::error::Error;
pub use crate::layout::prelude::*;
pub use crate::syntax::prelude::*;
pub use crate::size::{Size, Size2D, SizeBox, ValueBox, ScaleSize, FSize, PSize};
pub use crate::style::{LayoutStyle, PageStyle, TextStyle};
pub use Command::*;
}
/// Parse a function from source code.
pub trait Parse {
type Meta: Clone;
/// Parse the header and body into this function given a context.
fn parse(
header: FuncHeader,
body: Option<(Position, &str)>,
ctx: ParseContext,
metadata: Self::Meta,
) -> Parsed<Self> where Self: Sized;
}
/// A function which parses the source of a function into a model type which
/// implements [`Model`].
type Parser = dyn Fn(
FuncHeader,
Option<(Position, &str)>,
ParseContext,
) -> Parsed<Box<dyn Model>>;
/// A sequence of layouting commands.
pub type Commands<'a> = Vec<Command<'a>>;
/// Layouting commands from functions to the typesetting engine.
#[derive(Debug)]
pub enum Command<'a> {
LayoutSyntaxModel(&'a SyntaxModel),
Add(Layout),
AddMultiple(MultiLayout),
SpacingFunc(Size, SpacingKind, GenericAxis),
FinishLine,
FinishSpace,
BreakParagraph,
BreakPage,
SetTextStyle(TextStyle),
SetPageStyle(PageStyle),
SetAlignment(LayoutAlignment),
SetAxes(LayoutAxes),
}
/// A map from identifiers to function parsers.
pub struct Scope {
parsers: HashMap<String, Box<Parser>>,
fallback: Box<Parser>
}
impl Scope {
/// Create a new empty scope with a fallback parser that is invoked when no
/// match is found.
pub fn new<F>() -> Scope
where F: Parse<Meta=()> + Model + 'static {
Scope {
parsers: HashMap::new(),
fallback: parser::<F>(()),
}
}
/// Create a new scope with the standard functions contained.
pub fn with_std() -> Scope {
crate::library::std()
}
/// Associate the given name with a type that is parseable into a function.
pub fn add<F>(&mut self, name: &str)
where F: Parse<Meta=()> + Model + 'static {
self.add_with_metadata::<F>(name, ());
}
/// Add a parseable type with additional metadata that is given to the
/// parser (other than the default of `()`).
pub fn add_with_metadata<F>(&mut self, name: &str, metadata: <F as Parse>::Meta)
where F: Parse + Model + 'static {
self.parsers.insert(
name.to_owned(),
parser::<F>(metadata),
);
}
/// Return the parser with the given name if there is one.
pub fn get_parser(&self, name: &str) -> Result<&Parser, &Parser> {
self.parsers.get(name)
.map(|x| &**x)
.ok_or_else(|| &*self.fallback)
}
/// Return the fallback parser.
pub fn get_fallback_parser(&self) -> &Parser {
&*self.fallback
}
}
impl Debug for Scope {
fn fmt(&self, f: &mut Formatter) -> fmt::Result {
write!(f, "Scope ")?;
write!(f, "{:?}", self.parsers.keys())
}
}
fn parser<F>(metadata: <F as Parse>::Meta) -> Box<Parser> where F: Parse + Model + 'static {
Box::new(move |h, b, c| {
F::parse(h, b, c, metadata.clone())
.map(|model| Box::new(model) as Box<dyn Model>)
})
}
|
