htmls/parser/
index.rs

1use super::{Parser, literal};
2use crate::lexer::Token;
3use crate::parser::ast::{IndexNode, Node};
4use crate::parser::error::ParseError;
5
6/// 解析索引选择
7pub fn parse_index(it: &mut Parser, mut node: Node) -> Result<Node, ParseError> {
8    if let Some((Token::Colon, _, _)) = &it.current_token {
9        node = parse_index_selector(it, node)?;
10    }
11
12    Ok(node)
13}
14
15/// 解析索引选择器
16pub fn parse_index_selector(it: &mut Parser, node: Node) -> Result<Node, ParseError> {
17    if !it.check_token(&Token::Colon) {
18        let (line, column) = it.get_current_position();
19        let current = it.get_current_token_str();
20        return Err(ParseError::unexpected_token(":", &current, line, column));
21    }
22
23    it.consume_token(&Token::Colon)?;
24
25    it.check_depth()?;
26
27    let index_node = match &it.current_token {
28        Some((Token::Colon, _, _)) => {
29            it.read_token();
30            let end_index = if let Some((Token::Colon, _, _)) = &it.current_token {
31                it.read_token();
32                None
33            } else {
34                Some(literal::parse_literal(it)?)
35            };
36
37            let step_value = if let Some((Token::Colon, _, _)) = &it.current_token {
38                it.read_token();
39                Some(literal::parse_literal(it)?)
40            } else {
41                match literal::parse_literal(it) {
42                    Ok(step) => Some(step),
43                    Err(_) => None,
44                }
45            };
46
47            IndexNode::Range(None, end_index, step_value)
48        }
49        _ => {
50            let start_index = literal::parse_literal(it)?;
51            match &it.current_token {
52                Some((Token::Colon, _, _)) => {
53                    it.read_token();
54                    let end_index = if let Some((Token::Colon, _, _)) = &it.current_token {
55                        it.read_token();
56                        None
57                    } else {
58                        Some(literal::parse_literal(it)?)
59                    };
60
61                    let step_value = if let Some((Token::Colon, _, _)) = &it.current_token {
62                        it.read_token();
63                        Some(literal::parse_literal(it)?)
64                    } else {
65                        match literal::parse_literal(it) {
66                            Ok(step) => Some(step),
67                            Err(_) => None,
68                        }
69                    };
70
71                    IndexNode::Range(Some(start_index), end_index, step_value)
72                }
73                Some((Token::Comma, _, _)) => {
74                    it.read_token();
75
76                    let mut indexs = vec![start_index];
77
78                    while let Some((Token::Comma, _, _)) = &it.current_token {
79                        it.read_token();
80                        let index = literal::parse_literal(it)?;
81                        indexs.push(index);
82                    }
83
84                    IndexNode::Multiple(indexs)
85                }
86                _ => IndexNode::Single(start_index),
87            }
88        }
89    };
90
91    it.decrease_depth();
92
93    Ok(Node::IndexSelection(Box::new(node), Box::new(index_node)))
94}
htmls/parser/index.rs

htmls/parser/
index.rs
