tokit 0.0.0

Blazing fast parser combinators: parse-while-lexing (zero-copy), deterministic LALR-style parsing, no backtracking. Flexible emitters for fail-fast runtime or greedy compiler diagnostics
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137

use super::*;

/// a
#[derive(Clone, Debug, PartialEq, Eq, Hash)]
pub struct PeekThenChoice<P, H, L, Ctx, W, Lang: ?Sized = ()> {
  parser: P,
  handler: H,
  _capacity: PhantomData<W>,
  _ctx: PhantomData<Ctx>,
  _l: PhantomData<L>,
  _lang: PhantomData<Lang>,
}

impl<P, H, L, Ctx, W: Window, Lang: ?Sized> PeekThenChoice<P, H, L, Ctx, W, Lang> {
  /// Creates a new `PeekThenChoice` combinator for the specified language.
  #[cfg_attr(not(tarpaulin), inline(always))]
  pub(super) const fn of<'inp, O>(parser: P, condition: H) -> Self
  where
    L: Lexer<'inp>,
    Ctx: ParseContext<'inp, L, Lang>,
    P: ParseChoice<'inp, L, O, Ctx, Lang>,
    H: FnMut(
      Peeked<'_, 'inp, L, W>,
      &mut Ctx::Emitter,
    ) -> Result<P::Id, <Ctx::Emitter as Emitter<'inp, L, Lang>>::Error>,
  {
    Self {
      parser,
      handler: condition,
      _capacity: PhantomData,
      _ctx: PhantomData,
      _l: PhantomData,
      _lang: PhantomData,
    }
  }

  /// Creates a new `PeekThenChoice` combinator for the specified language.
  #[cfg_attr(not(tarpaulin), inline(always))]
  pub(super) const fn or_not_of<'inp, O>(parser: P, condition: H) -> OrNot<Self>
  where
    L: Lexer<'inp>,
    Ctx: ParseContext<'inp, L, Lang>,
    P: ParseChoice<'inp, L, O, Ctx, Lang>,
    H: FnMut(
      Peeked<'_, 'inp, L, W>,
      &mut Ctx::Emitter,
    ) -> Result<Option<P::Id>, <Ctx::Emitter as Emitter<'inp, L, Lang>>::Error>,
  {
    OrNot::new(Self {
      parser,
      handler: condition,
      _capacity: PhantomData,
      _ctx: PhantomData,
      _l: PhantomData,
      _lang: PhantomData,
    })
  }
}

impl<'inp, P, H, L, O, Ctx, Lang, W: Window> ParseInput<'inp, L, O, Ctx, Lang>
  for PeekThenChoice<P, H, L, Ctx, W, Lang>
where
  P: ParseChoice<'inp, L, O, Ctx, Lang>,
  H: FnMut(
    Peeked<'_, 'inp, L, W>,
    &mut Ctx::Emitter,
  ) -> Result<P::Id, <Ctx::Emitter as Emitter<'inp, L, Lang>>::Error>,
  L: Lexer<'inp>,
  Ctx: ParseContext<'inp, L, Lang>,
  Lang: ?Sized,
{
  #[cfg_attr(not(tarpaulin), inline(always))]
  fn parse_input(
    &mut self,
    inp: &mut InputRef<'inp, '_, L, Ctx, Lang>,
  ) -> Result<O, <Ctx::Emitter as Emitter<'inp, L, Lang>>::Error> {
    let id = {
      let (output, emitter) = inp.sync_until_token_then_peek_with_emitter::<W>()?;
      (self.handler)(output, emitter)?
    };
    self.parser.parse_choice(inp, &id)
  }
}

impl<'inp, P, H, L, O, Ctx, Lang, W: Window> ParseInput<'inp, L, Option<O>, Ctx, Lang>
  for OrNot<PeekThenChoice<P, H, L, Ctx, W>>
where
  P: ParseChoice<'inp, L, O, Ctx, Lang>,
  H: FnMut(
    Peeked<'_, 'inp, L, W>,
    &mut Ctx::Emitter,
  ) -> Result<Option<P::Id>, <Ctx::Emitter as Emitter<'inp, L, Lang>>::Error>,
  L: Lexer<'inp>,
  Ctx: ParseContext<'inp, L, Lang>,
  Lang: ?Sized,
{
  #[cfg_attr(not(tarpaulin), inline(always))]
  fn parse_input(
    &mut self,
    inp: &mut InputRef<'inp, '_, L, Ctx, Lang>,
  ) -> Result<Option<O>, <Ctx::Emitter as Emitter<'inp, L, Lang>>::Error> {
    let id = {
      let (output, emitter) = inp.sync_until_token_then_peek_with_emitter::<W>()?;

      if output.is_empty() {
        return Ok(None);
      }

      (self.0.handler)(output, emitter)?
    };
    match id {
      Some(id) => self.0.parser.parse_choice(inp, &id).map(Some),
      None => Ok(None),
    }
  }
}

#[cfg(test)]
mod tests {
  use generic_arraydeque::typenum::U2;

  use crate::lexer::{DummyLexer, DummyToken};

  use super::*;

  fn assert_peek_then_choice_parse_impl<'inp>() -> impl Parse<'inp, DummyLexer, DummyToken, ()> {
    Parser::new().apply(
      (Any::new(), Any::new())
        .peek_then_choice::<_, U2>(|_toks, _| Ok(deranged::RangedU8::<0, 1>::new(0).unwrap())),
    )
  }

  #[test]
  fn assert_parse_impl() {
    let _ = assert_peek_then_choice_parse_impl();
  }
}