Files
orchid/orchid-std/src/macros/rule/matcher.rs

88 lines
2.9 KiB
Rust

use std::fmt;
use itertools::Itertools;
use orchid_base::error::OrcRes;
use orchid_base::interner::{Interner, Tok};
use orchid_base::location::Pos;
use orchid_base::name::Sym;
use super::any_match::any_match;
use super::build::{mk_any, mk_vec};
use super::shared::{AnyMatcher, VecMatcher};
use super::state::{MatchState, StateEntry};
use super::vec_attrs::vec_attrs;
use super::vec_match::vec_match;
use crate::macros::mactree::{Ph, PhKind};
use crate::macros::{MacTok, MacTree};
pub struct NamedMatcher {
inner: AnyMatcher,
head: Sym,
after_tok: IStr,
}
impl NamedMatcher {
pub async fn new(pattern: &[MacTree], i: &Interner) -> OrcRes<Self> {
let head = match pattern.first().map(|tree| tree.tok()) {
Some(MacTok::Name(name)) => name.clone(),
_ => panic!("Named matchers must begin with a name"),
};
let after_tok = i.i("::after").await;
let inner = match pattern.last().and_then(vec_attrs).is_some() {
true => mk_any(pattern, i).await?,
false => {
let kind = PhKind::Vector { priority: 0, at_least_one: false };
let suffix = [MacTok::Ph(Ph { name: after_tok.clone(), kind }).at(Pos::None)];
mk_any(&pattern.iter().cloned().chain(suffix).collect_vec(), i).await?
},
};
Ok(Self { after_tok, inner, head })
}
pub fn head(&self) -> Sym { self.head.clone() }
/// Also returns the tail, if any, which should be matched further
/// Note that due to how priod works below, the main usable information from
/// the tail is its length
pub fn apply<'a>(
&self,
seq: &'a [MacTree],
save_loc: impl Fn(Sym) -> bool,
) -> Option<(MatchState<'a>, &'a [MacTree])> {
let mut state = any_match(&self.inner, seq, &save_loc)?;
match state.remove(self.after_tok.clone()) {
Some(StateEntry::Scalar(_)) => panic!("{} can never be a scalar entry!", self.after_tok),
Some(StateEntry::Vec(v)) => Some((state, v)),
None => Some((state, &[][..])),
}
}
}
impl fmt::Display for NamedMatcher {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { self.inner.fmt(f) }
}
impl fmt::Debug for NamedMatcher {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { write!(f, "NamedMatcher({self})") }
}
pub struct PriodMatcher(VecMatcher);
impl PriodMatcher {
pub async fn new(pattern: &[MacTree], i: &Interner) -> OrcRes<Self> {
assert!(
pattern.first().and_then(vec_attrs).is_some() && pattern.last().and_then(vec_attrs).is_some(),
"Prioritized matchers must start and end with a vectorial",
);
Ok(Self(mk_vec(pattern, i).await?))
}
/// tokens before the offset always match the prefix
pub fn apply<'a>(
&self,
seq: &'a [MacTree],
save_loc: impl Fn(Sym) -> bool,
) -> Option<MatchState<'a>> {
vec_match(&self.0, seq, &save_loc)
}
}
impl fmt::Display for PriodMatcher {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { self.0.fmt(f) }
}
impl fmt::Debug for PriodMatcher {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { write!(f, "PriodMatcher({self})") }
}