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
138
139
140
141
142
143
144
145
146
|
/// This module parses a raw `tt::TokenStream` into macro-by-example token
/// stream. This is a *mostly* identify function, expect for handling of
/// `$var:tt_kind` and `$(repeat),*` constructs.
use crate::ParseError;
use crate::tt_cursor::TtCursor;
pub(crate) fn parse(tt: &tt::Subtree) -> Result<crate::MacroRules, ParseError> {
let mut parser = TtCursor::new(tt);
let mut rules = Vec::new();
while !parser.is_eof() {
rules.push(parse_rule(&mut parser)?);
if let Err(e) = parser.expect_char(';') {
if !parser.is_eof() {
return Err(e);
}
break;
}
}
Ok(crate::MacroRules { rules })
}
fn parse_rule(p: &mut TtCursor) -> Result<crate::Rule, ParseError> {
let lhs = parse_subtree(p.eat_subtree()?, false)?;
p.expect_char('=')?;
p.expect_char('>')?;
let mut rhs = parse_subtree(p.eat_subtree()?, true)?;
rhs.delimiter = crate::Delimiter::None;
Ok(crate::Rule { lhs, rhs })
}
fn parse_subtree(tt: &tt::Subtree, transcriber: bool) -> Result<crate::Subtree, ParseError> {
let mut token_trees = Vec::new();
let mut p = TtCursor::new(tt);
while let Some(tt) = p.eat() {
let child: crate::TokenTree = match tt {
tt::TokenTree::Leaf(leaf) => match leaf {
tt::Leaf::Punct(tt::Punct { char: '$', .. }) => {
if p.at_ident().is_some() {
crate::Leaf::from(parse_var(&mut p, transcriber)?).into()
} else {
parse_repeat(&mut p, transcriber)?.into()
}
}
tt::Leaf::Punct(punct) => crate::Leaf::from(*punct).into(),
tt::Leaf::Ident(tt::Ident { text, id: _ }) => {
crate::Leaf::from(crate::Ident { text: text.clone() }).into()
}
tt::Leaf::Literal(tt::Literal { text }) => {
crate::Leaf::from(crate::Literal { text: text.clone() }).into()
}
},
tt::TokenTree::Subtree(subtree) => parse_subtree(&subtree, transcriber)?.into(),
};
token_trees.push(child);
}
Ok(crate::Subtree { token_trees, delimiter: tt.delimiter })
}
fn parse_var(p: &mut TtCursor, transcriber: bool) -> Result<crate::Var, ParseError> {
let ident = p.eat_ident().unwrap();
let text = ident.text.clone();
let kind = if !transcriber && p.at_char(':') {
p.bump();
if let Some(ident) = p.eat_ident() {
Some(ident.text.clone())
} else {
p.rev_bump();
None
}
} else {
None
};
Ok(crate::Var { text, kind })
}
fn parse_repeat(p: &mut TtCursor, transcriber: bool) -> Result<crate::Repeat, ParseError> {
let subtree = p.eat_subtree().unwrap();
let mut subtree = parse_subtree(subtree, transcriber)?;
subtree.delimiter = crate::Delimiter::None;
let sep = p.eat_punct().ok_or(ParseError::Expected(String::from("separator")))?;
let (separator, rep) = match sep.char {
'*' | '+' | '?' => (None, sep.char),
char => {
(Some(char), p.eat_punct().ok_or(ParseError::Expected(String::from("separator")))?.char)
}
};
let kind = match rep {
'*' => crate::RepeatKind::ZeroOrMore,
'+' => crate::RepeatKind::OneOrMore,
'?' => crate::RepeatKind::ZeroOrOne,
_ => return Err(ParseError::Expected(String::from("repeat"))),
};
Ok(crate::Repeat { subtree, kind, separator })
}
#[cfg(test)]
mod tests {
use ra_syntax::{ast, AstNode};
use super::*;
use crate::ast_to_token_tree;
#[test]
fn test_invalid_parse() {
expect_err("invalid", "subtree");
is_valid("($i:ident) => ()");
expect_err("$i:ident => ()", "subtree");
expect_err("($i:ident) ()", "`=`");
expect_err("($($i:ident)_) => ()", "separator");
}
fn expect_err(macro_body: &str, expected: &str) {
assert_eq!(
create_rules(&format_macro(macro_body)),
Err(ParseError::Expected(String::from(expected)))
);
}
fn is_valid(macro_body: &str) {
assert!(create_rules(&format_macro(macro_body)).is_ok());
}
fn format_macro(macro_body: &str) -> String {
format!(
"
macro_rules! foo {{
{}
}}
",
macro_body
)
}
fn create_rules(macro_definition: &str) -> Result<crate::MacroRules, ParseError> {
let source_file = ast::SourceFile::parse(macro_definition);
let macro_definition =
source_file.syntax().descendants().find_map(ast::MacroCall::cast).unwrap();
let (definition_tt, _) = ast_to_token_tree(macro_definition.token_tree().unwrap()).unwrap();
parse(&definition_tt)
}
}
|
