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-rw-r--r--src/parser/event_parser/mod.rs48
1 files changed, 48 insertions, 0 deletions
diff --git a/src/parser/event_parser/mod.rs b/src/parser/event_parser/mod.rs
index 65aea017b..1bb943b5d 100644
--- a/src/parser/event_parser/mod.rs
+++ b/src/parser/event_parser/mod.rs
@@ -4,17 +4,65 @@ use {SyntaxKind, Token};
4mod parser; 4mod parser;
5mod grammar; 5mod grammar;
6 6
7
8/// `Parser` produces a flat list of `Event`s.
9/// They are converted to a tree-structure in
10/// a separate pass, via `TreeBuilder`.
7#[derive(Debug)] 11#[derive(Debug)]
8pub(crate) enum Event { 12pub(crate) enum Event {
13 /// This event signifies the start of the node.
14 /// It should be either abandoned (in which case the
15 /// `kind` is `TOMBSTONE`, and the event is ignored),
16 /// or completed via a `Finish` event.
17 ///
18 /// All tokens between a `Start` and a `Finish` would
19 /// become the children of the respective node.
20 ///
21 /// For left-recursive syntactic constructs, the parser produces
22 /// a child node before it sees a parent. `forward_parent`
23 /// exists to allow to tweak parent-child relationships.
24 ///
25 /// Consider this path
26 ///
27 /// foo::bar
28 ///
29 /// The events for it would look like this:
30 ///
31 ///
32 /// START(PATH) IDENT('foo') FINISH START(PATH) COLONCOLON IDENT('bar') FINISH
33 /// | /\
34 /// | |
35 /// +------forward-parent------+
36 ///
37 /// And the tree would look like this
38 ///
39 /// +--PATH---------+
40 /// | | |
41 /// | | |
42 /// | '::' 'bar'
43 /// |
44 /// PATH
45 /// |
46 /// 'foo'
47 ///
48 /// See also `CompleteMarker::precede`.
9 Start { 49 Start {
10 kind: SyntaxKind, 50 kind: SyntaxKind,
11 forward_parent: Option<u32>, 51 forward_parent: Option<u32>,
12 }, 52 },
53
54 /// Complete the previous `Start` event
13 Finish, 55 Finish,
56
57 /// Produce a single leaf-element.
58 /// `n_raw_tokens` is used to glue complex contextual tokens.
59 /// For example, lexer tokenizes `>>` as `>`, `>`, and
60 /// `n_raw_tokens = 2` is used to produced a single `>>`.
14 Token { 61 Token {
15 kind: SyntaxKind, 62 kind: SyntaxKind,
16 n_raw_tokens: u8, 63 n_raw_tokens: u8,
17 }, 64 },
65
18 Error { 66 Error {
19 message: String, 67 message: String,
20 }, 68 },