libgrust/libproc_macro/punct.rs

   1 // Copyright (C) 2023-2024 Free Software Foundation, Inc.
   2 //
   3 // This file is part of the GNU Proc Macro Library.  This library is free
   4 // software; you can redistribute it and/or modify it under the
   5 // terms of the GNU General Public License as published by the
   6 // Free Software Foundation; either version 3, or (at your option)
   7 // any later version.
   8
   9 // This library is distributed in the hope that it will be useful,
  10 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12 // GNU General Public License for more details.
  13
  14 // Under Section 7 of GPL version 3, you are granted additional
  15 // permissions described in the GCC Runtime Library Exception, version
  16 // 3.1, as published by the Free Software Foundation.
  17
  18 // You should have received a copy of the GNU General Public License and
  19 // a copy of the GCC Runtime Library Exception along with this program;
  20 // see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
  21 // <http://www.gnu.org/licenses/>.
  22
  23 use bridge;
  24 use std::convert::TryInto;
  25 use std::fmt;
  26 use Span;
  27
  28 /// Describes the context of a [`Punct`] relatively to the next token.
  29 #[repr(C)]
  30 #[derive(Copy, Clone, Debug, PartialEq, Eq)]
  31 pub enum Spacing {
  32     /// A [`Punct`] is not immediately followed by another `Punct`.
  33     Alone,
  34     /// A [`Punct`] is immediately followed by another `Punct` and can be
  35     /// combined into a multi-character operator.
  36     Joint,
  37 }
  38
  39 /// Single punctuation character such as `+`, `-` or `#`.
  40 ///
  41 /// Multi-character operators like `+=` are represented as two instances of
  42 /// `Punct` with different forms of `Spacing` returned.
  43 #[derive(Clone)]
  44 pub struct Punct(pub(crate) bridge::punct::Punct);
  45
  46 impl Punct {
  47     /// Creates a new `Punct` from a given character and spacing.
  48     ///
  49     /// # Arguments
  50     ///
  51     /// * `ch` - The punctuation character.
  52     /// * `spacing` - The link between this character and the next one.
  53     ///
  54     /// # Panics
  55     ///
  56     /// This function will panic if the `ch` argument is not a valid
  57     /// punctuation character allowed by the language.
  58     pub fn new(ch: char, spacing: Spacing) -> Self {
  59         Punct(bridge::punct::Punct::new(ch, spacing))
  60     }
  61
  62     /// Get the value for this punctuation character as `char`.
  63     pub fn as_char(&self) -> char {
  64         self.0
  65             .ch
  66             .try_into()
  67             .expect("Cannot convert from u32 to char")
  68     }
  69
  70     /// Get the [`Spacing`] of this punctuation character, indicating whether
  71     /// the following character can be combined into a multi-character operator
  72     /// or not.
  73     pub fn spacing(&self) -> Spacing {
  74         self.0.spacing
  75     }
  76
  77     /// Get the [`Span`] for this punctuation character.
  78     pub fn span(&self) -> Span {
  79         Span(self.0.span())
  80     }
  81
  82     /// Set the span for this punctuation character.
  83     ///
  84     /// # Arguments
  85     ///
  86     /// * `span` - The new span value.
  87     pub fn set_span(&mut self, span: Span) {
  88         self.0.set_span(span.0);
  89     }
  90 }
  91
  92 impl fmt::Display for Punct {
  93     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
  94         self.0.fmt(f)
  95     }
  96 }
  97
  98 impl fmt::Debug for Punct {
  99     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
 100         self.0.fmt(f)
 101     }
 102 }
 103
 104 impl PartialEq<char> for Punct {
 105     fn eq(&self, rhs: &char) -> bool {
 106         self.as_char() == *rhs
 107     }
 108 }
 109
 110 impl PartialEq<Punct> for char {
 111     fn eq(&self, rhs: &Punct) -> bool {
 112         *self == rhs.as_char()
 113     }
 114 }