diff options
Diffstat (limited to 'crates/ra_mbe/src/mbe_parser.rs')
-rw-r--r-- | crates/ra_mbe/src/mbe_parser.rs | 83 |
1 files changed, 68 insertions, 15 deletions
diff --git a/crates/ra_mbe/src/mbe_parser.rs b/crates/ra_mbe/src/mbe_parser.rs index 58e2533f1..e3669f66c 100644 --- a/crates/ra_mbe/src/mbe_parser.rs +++ b/crates/ra_mbe/src/mbe_parser.rs | |||
@@ -1,33 +1,34 @@ | |||
1 | /// This module parses a raw `tt::TokenStream` into macro-by-example token | 1 | /// This module parses a raw `tt::TokenStream` into macro-by-example token |
2 | /// stream. This is a *mostly* identify function, expect for handling of | 2 | /// stream. This is a *mostly* identify function, expect for handling of |
3 | /// `$var:tt_kind` and `$(repeat),*` constructs. | 3 | /// `$var:tt_kind` and `$(repeat),*` constructs. |
4 | use crate::ParseError; | ||
4 | use crate::tt_cursor::TtCursor; | 5 | use crate::tt_cursor::TtCursor; |
5 | 6 | ||
6 | pub(crate) fn parse(tt: &tt::Subtree) -> Option<crate::MacroRules> { | 7 | pub(crate) fn parse(tt: &tt::Subtree) -> Result<crate::MacroRules, ParseError> { |
7 | let mut parser = TtCursor::new(tt); | 8 | let mut parser = TtCursor::new(tt); |
8 | let mut rules = Vec::new(); | 9 | let mut rules = Vec::new(); |
9 | while !parser.is_eof() { | 10 | while !parser.is_eof() { |
10 | rules.push(parse_rule(&mut parser)?); | 11 | rules.push(parse_rule(&mut parser)?); |
11 | if parser.expect_char(';') == None { | 12 | if let Err(e) = parser.expect_char(';') { |
12 | if !parser.is_eof() { | 13 | if !parser.is_eof() { |
13 | return None; | 14 | return Err(e); |
14 | } | 15 | } |
15 | break; | 16 | break; |
16 | } | 17 | } |
17 | } | 18 | } |
18 | Some(crate::MacroRules { rules }) | 19 | Ok(crate::MacroRules { rules }) |
19 | } | 20 | } |
20 | 21 | ||
21 | fn parse_rule(p: &mut TtCursor) -> Option<crate::Rule> { | 22 | fn parse_rule(p: &mut TtCursor) -> Result<crate::Rule, ParseError> { |
22 | let lhs = parse_subtree(p.eat_subtree()?)?; | 23 | let lhs = parse_subtree(p.eat_subtree()?)?; |
23 | p.expect_char('=')?; | 24 | p.expect_char('=')?; |
24 | p.expect_char('>')?; | 25 | p.expect_char('>')?; |
25 | let mut rhs = parse_subtree(p.eat_subtree()?)?; | 26 | let mut rhs = parse_subtree(p.eat_subtree()?)?; |
26 | rhs.delimiter = crate::Delimiter::None; | 27 | rhs.delimiter = crate::Delimiter::None; |
27 | Some(crate::Rule { lhs, rhs }) | 28 | Ok(crate::Rule { lhs, rhs }) |
28 | } | 29 | } |
29 | 30 | ||
30 | fn parse_subtree(tt: &tt::Subtree) -> Option<crate::Subtree> { | 31 | fn parse_subtree(tt: &tt::Subtree) -> Result<crate::Subtree, ParseError> { |
31 | let mut token_trees = Vec::new(); | 32 | let mut token_trees = Vec::new(); |
32 | let mut p = TtCursor::new(tt); | 33 | let mut p = TtCursor::new(tt); |
33 | while let Some(tt) = p.eat() { | 34 | while let Some(tt) = p.eat() { |
@@ -52,10 +53,10 @@ fn parse_subtree(tt: &tt::Subtree) -> Option<crate::Subtree> { | |||
52 | }; | 53 | }; |
53 | token_trees.push(child); | 54 | token_trees.push(child); |
54 | } | 55 | } |
55 | Some(crate::Subtree { token_trees, delimiter: tt.delimiter }) | 56 | Ok(crate::Subtree { token_trees, delimiter: tt.delimiter }) |
56 | } | 57 | } |
57 | 58 | ||
58 | fn parse_var(p: &mut TtCursor) -> Option<crate::Var> { | 59 | fn parse_var(p: &mut TtCursor) -> Result<crate::Var, ParseError> { |
59 | let ident = p.eat_ident().unwrap(); | 60 | let ident = p.eat_ident().unwrap(); |
60 | let text = ident.text.clone(); | 61 | let text = ident.text.clone(); |
61 | let kind = if p.at_char(':') { | 62 | let kind = if p.at_char(':') { |
@@ -69,25 +70,77 @@ fn parse_var(p: &mut TtCursor) -> Option<crate::Var> { | |||
69 | } else { | 70 | } else { |
70 | None | 71 | None |
71 | }; | 72 | }; |
72 | Some(crate::Var { text, kind }) | 73 | Ok(crate::Var { text, kind }) |
73 | } | 74 | } |
74 | 75 | ||
75 | fn parse_repeat(p: &mut TtCursor) -> Option<crate::Repeat> { | 76 | fn parse_repeat(p: &mut TtCursor) -> Result<crate::Repeat, ParseError> { |
76 | let subtree = p.eat_subtree().unwrap(); | 77 | let subtree = p.eat_subtree().unwrap(); |
77 | let mut subtree = parse_subtree(subtree)?; | 78 | let mut subtree = parse_subtree(subtree)?; |
78 | subtree.delimiter = crate::Delimiter::None; | 79 | subtree.delimiter = crate::Delimiter::None; |
79 | let sep = p.eat_punct()?; | 80 | let sep = p.eat_punct().ok_or(ParseError::Expected(String::from("separator")))?; |
80 | let (separator, rep) = match sep.char { | 81 | let (separator, rep) = match sep.char { |
81 | '*' | '+' | '?' => (None, sep.char), | 82 | '*' | '+' | '?' => (None, sep.char), |
82 | char => (Some(char), p.eat_punct()?.char), | 83 | char => { |
84 | (Some(char), p.eat_punct().ok_or(ParseError::Expected(String::from("separator")))?.char) | ||
85 | } | ||
83 | }; | 86 | }; |
84 | 87 | ||
85 | let kind = match rep { | 88 | let kind = match rep { |
86 | '*' => crate::RepeatKind::ZeroOrMore, | 89 | '*' => crate::RepeatKind::ZeroOrMore, |
87 | '+' => crate::RepeatKind::OneOrMore, | 90 | '+' => crate::RepeatKind::OneOrMore, |
88 | '?' => crate::RepeatKind::ZeroOrOne, | 91 | '?' => crate::RepeatKind::ZeroOrOne, |
89 | _ => return None, | 92 | _ => return Err(ParseError::Expected(String::from("repeat"))), |
90 | }; | 93 | }; |
91 | p.bump(); | 94 | p.bump(); |
92 | Some(crate::Repeat { subtree, kind, separator }) | 95 | Ok(crate::Repeat { subtree, kind, separator }) |
96 | } | ||
97 | |||
98 | #[cfg(test)] | ||
99 | mod tests { | ||
100 | use ra_syntax::{ast, AstNode}; | ||
101 | |||
102 | use super::*; | ||
103 | use crate::ast_to_token_tree; | ||
104 | |||
105 | #[test] | ||
106 | fn test_invalid_parse() { | ||
107 | expect_err("invalid", "subtree"); | ||
108 | |||
109 | is_valid("($i:ident) => ()"); | ||
110 | expect_err("$i:ident => ()", "subtree"); | ||
111 | expect_err("($i:ident) ()", "`=`"); | ||
112 | expect_err("($($i:ident)_) => ()", "separator"); | ||
113 | } | ||
114 | |||
115 | fn expect_err(macro_body: &str, expected: &str) { | ||
116 | assert_eq!( | ||
117 | create_rules(&format_macro(macro_body)), | ||
118 | Err(ParseError::Expected(String::from(expected))) | ||
119 | ); | ||
120 | } | ||
121 | |||
122 | fn is_valid(macro_body: &str) { | ||
123 | assert!(create_rules(&format_macro(macro_body)).is_ok()); | ||
124 | } | ||
125 | |||
126 | fn format_macro(macro_body: &str) -> String { | ||
127 | format!( | ||
128 | " | ||
129 | macro_rules! foo {{ | ||
130 | {} | ||
131 | }} | ||
132 | ", | ||
133 | macro_body | ||
134 | ) | ||
135 | } | ||
136 | |||
137 | fn create_rules(macro_definition: &str) -> Result<crate::MacroRules, ParseError> { | ||
138 | let source_file = ast::SourceFile::parse(macro_definition); | ||
139 | let macro_definition = | ||
140 | source_file.syntax().descendants().find_map(ast::MacroCall::cast).unwrap(); | ||
141 | |||
142 | let (definition_tt, _) = ast_to_token_tree(macro_definition.token_tree().unwrap()).unwrap(); | ||
143 | parse(&definition_tt) | ||
144 | } | ||
145 | |||
93 | } | 146 | } |