lwb_parser/parser/peg/
parse_pair.rs

1use crate::sources::span::Span;
2use itertools::Itertools;
3use std::fmt::{Display, Formatter};
4
5/// A parse pair is a way of representing an AST, without actually using any datatypes that depend on the language definition.
6/// This represents a parse pair for a sort. It stores which constructor was chosen.
7#[derive(Debug, Clone)]
8pub struct ParsePairSort<'src> {
9    pub sort: &'src str,
10    pub constructor_name: &'src str,
11    pub constructor_value: ParsePairExpression<'src>,
12}
13
14impl ParsePairSort<'_> {
15    /// What span does this parse pair occupy?
16    pub fn span(&self) -> Span {
17        self.constructor_value.span()
18    }
19}
20
21impl<'src> Display for ParsePairSort<'src> {
22    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
23        // write!(f, "{}.{}({})", self.sort, self.constructor_name, self.constructor_value)
24        write!(f, "{}({})", self.constructor_name, self.constructor_value)
25    }
26}
27
28/// A parse pair is a way of representing an AST, without actually using any datatypes that depend on the language definition.
29/// This represents a parse pair for a constructor. Each constructor generates one of the variants of this enum.
30#[derive(Debug, Clone)]
31pub enum ParsePairExpression<'src> {
32    /// This is generated when another sort is mentioned in the definition of this sort.
33    /// That sort is parsed and the result is stored here.
34    Sort(Span, Box<ParsePairSort<'src>>),
35    /// This is generated when a list of constructors is executed. This can be generated by Sequence or Repeat.
36    List(Span, Vec<ParsePairExpression<'src>>),
37    /// This is generated when a Choice was made. The first argument is which choice was made, the second the parsed constructor.
38    Choice(Span, usize, Box<ParsePairExpression<'src>>),
39    /// This is generated when no useful information needed to be recorded here, but still a placeholder is needed to keep track of the span.
40    /// Generated by Positive and Negative, as the actual values that were parsed in Positive and Negative are irrelevant.
41    /// Generated by CharacterClass and Literal, as they don't generate values.
42    Empty(Span),
43    Error(Span),
44}
45
46impl<'src> ParsePairExpression<'src> {
47    /// What span does this parse pair occupy?
48    pub fn span(&self) -> Span {
49        match self {
50            ParsePairExpression::Sort(span, _) => span,
51            ParsePairExpression::List(span, _) => span,
52            ParsePairExpression::Choice(span, _, _) => span,
53            ParsePairExpression::Empty(span) => span,
54            ParsePairExpression::Error(span) => span,
55        }
56        .clone()
57    }
58}
59
60impl<'src> Display for ParsePairExpression<'src> {
61    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
62        match self {
63            ParsePairExpression::Sort(_, sort) => {
64                write!(f, "{}", sort)
65            }
66            ParsePairExpression::List(_, exprs) => {
67                write!(f, "[{}]", exprs.iter().map(|e| e.to_string()).join(", "))
68            }
69            ParsePairExpression::Choice(_, num, child) => {
70                write!(f, "{}:{}", num, child)
71            }
72            ParsePairExpression::Empty(_) => {
73                write!(f, "_")
74            }
75            ParsePairExpression::Error(_) => {
76                write!(f, "#")
77            }
78        }
79    }
80}
lwb_parser/parser/peg/parse_pair.rs

lwb_parser/parser/peg/
parse_pair.rs
