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