85 lines
2.1 KiB
Rust
85 lines
2.1 KiB
Rust
use ordered_float::OrderedFloat;
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use std::{
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borrow::Cow,
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fmt::{Display, Write},
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hash::Hash,
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};
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pub type Span = std::ops::Range<usize>;
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/// A spanned item
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#[derive(Clone, Debug)]
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pub struct Spanned<T> {
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pub item: T,
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pub span: Span,
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}
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impl<T> Spanned<T> {
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pub fn new(item: T, span: Span) -> Self {
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Self { item, span }
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}
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}
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impl<T: Display> Display for Spanned<T> {
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fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
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write!(f, "{} \x1B[2m@ {:?}\x1B[22m", self.item, self.span)
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}
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}
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impl<T: PartialEq> PartialEq for Spanned<T> {
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fn eq(&self, other: &Self) -> bool {
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self.item == other.item
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}
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}
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impl<T: Hash> Hash for Spanned<T> {
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fn hash<H: std::hash::Hasher>(&self, state: &mut H) {
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self.item.hash(state);
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}
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}
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/// A Wisp AST
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#[derive(Debug, Clone, Hash, PartialEq)]
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pub enum Expr<'a> {
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List(Vec<Spanned<Self>>),
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Vector(Vec<Spanned<Self>>),
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Map(Vec<(Spanned<Self>, Spanned<Self>)>),
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Quote(Box<Spanned<Self>>),
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Symbol(Cow<'a, str>),
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Keyword(Cow<'a, str>),
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Number(OrderedFloat<f64>),
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String(Cow<'a, str>),
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}
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impl<'a> Display for Expr<'a> {
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fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
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match self {
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Self::List(list) => write_seq(f, list, "(", ")"),
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Self::Vector(vec) => write_seq(f, vec, "[", "]"),
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Self::Map(map) => write_seq(f, map.iter().map(|(k, v)| format!("{k} {v}")), "{", "}"),
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Self::Quote(expr) => write!(f, "'{expr}"),
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Self::Symbol(sym) => write!(f, "{sym}"),
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Self::Keyword(kw) => write!(f, ":{kw}"),
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Self::Number(n) => write!(f, "{n}"),
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Self::String(s) => write!(f, "\"{s}\""),
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}
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}
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}
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fn write_seq(
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f: &mut impl Write,
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iterable: impl IntoIterator<Item = impl Display>,
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delimiter_left: &str,
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delimiter_right: &str,
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) -> std::fmt::Result {
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let mut iter = iterable.into_iter();
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write!(f, "{delimiter_left}")?;
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if let Some(x) = iter.next() {
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write!(f, "{x}")?;
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}
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for x in iter {
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write!(f, " {x}")?;
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}
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write!(f, "{delimiter_right}")
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}
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