diff options
Diffstat (limited to 'language-web/src/main/js/language/folding.ts')
-rw-r--r-- | language-web/src/main/js/language/folding.ts | 115 |
1 files changed, 115 insertions, 0 deletions
diff --git a/language-web/src/main/js/language/folding.ts b/language-web/src/main/js/language/folding.ts new file mode 100644 index 00000000..5d51f796 --- /dev/null +++ b/language-web/src/main/js/language/folding.ts | |||
@@ -0,0 +1,115 @@ | |||
1 | import { EditorState } from '@codemirror/state'; | ||
2 | import type { SyntaxNode } from '@lezer/common'; | ||
3 | |||
4 | export type FoldRange = { from: number, to: number }; | ||
5 | |||
6 | /** | ||
7 | * Folds a block comment between its delimiters. | ||
8 | * | ||
9 | * @param node the node to fold | ||
10 | * @returns the folding range or `null` is there is nothing to fold | ||
11 | */ | ||
12 | export function foldBlockComment(node: SyntaxNode): FoldRange { | ||
13 | return { | ||
14 | from: node.from + 2, | ||
15 | to: node.to - 2, | ||
16 | }; | ||
17 | } | ||
18 | |||
19 | /** | ||
20 | * Folds a declaration after the first element if it appears on the opening line, | ||
21 | * otherwise folds after the opening keyword. | ||
22 | * | ||
23 | * @example | ||
24 | * First element on the opening line: | ||
25 | * ``` | ||
26 | * scope Family = 1, | ||
27 | * Person += 5..10. | ||
28 | * ``` | ||
29 | * becomes | ||
30 | * ``` | ||
31 | * scope Family = 1,[...]. | ||
32 | * ``` | ||
33 | * | ||
34 | * @example | ||
35 | * First element not on the opening line: | ||
36 | * ``` | ||
37 | * scope Family | ||
38 | * = 1, | ||
39 | * Person += 5..10. | ||
40 | * ``` | ||
41 | * becomes | ||
42 | * ``` | ||
43 | * scope [...]. | ||
44 | * ``` | ||
45 | * | ||
46 | * @param node the node to fold | ||
47 | * @param state the editor state | ||
48 | * @returns the folding range or `null` is there is nothing to fold | ||
49 | */ | ||
50 | export function foldDeclaration(node: SyntaxNode, state: EditorState): FoldRange | null { | ||
51 | const { firstChild: open, lastChild: close } = node; | ||
52 | if (open === null || close === null) { | ||
53 | return null; | ||
54 | } | ||
55 | const { cursor } = open; | ||
56 | const lineEnd = state.doc.lineAt(open.from).to; | ||
57 | let foldFrom = open.to; | ||
58 | while (cursor.next() && cursor.from < lineEnd) { | ||
59 | if (cursor.type.name === ',') { | ||
60 | foldFrom = cursor.to; | ||
61 | break; | ||
62 | } | ||
63 | } | ||
64 | return { | ||
65 | from: foldFrom, | ||
66 | to: close.from, | ||
67 | }; | ||
68 | } | ||
69 | |||
70 | /** | ||
71 | * Folds a node only if it has at least one sibling of the same type. | ||
72 | * | ||
73 | * The folding range will be the entire `node`. | ||
74 | * | ||
75 | * @param node the node to fold | ||
76 | * @returns the folding range or `null` is there is nothing to fold | ||
77 | */ | ||
78 | function foldWithSibling(node: SyntaxNode): FoldRange | null { | ||
79 | const { parent } = node; | ||
80 | if (parent === null) { | ||
81 | return null; | ||
82 | } | ||
83 | const { firstChild } = parent; | ||
84 | if (firstChild === null) { | ||
85 | return null; | ||
86 | } | ||
87 | const { cursor } = firstChild; | ||
88 | let nSiblings = 0; | ||
89 | while (cursor.nextSibling()) { | ||
90 | if (cursor.type === node.type) { | ||
91 | nSiblings += 1; | ||
92 | } | ||
93 | if (nSiblings >= 2) { | ||
94 | return { | ||
95 | from: node.from, | ||
96 | to: node.to, | ||
97 | }; | ||
98 | } | ||
99 | } | ||
100 | return null; | ||
101 | } | ||
102 | |||
103 | export function foldWholeNode(node: SyntaxNode): FoldRange { | ||
104 | return { | ||
105 | from: node.from, | ||
106 | to: node.to, | ||
107 | }; | ||
108 | } | ||
109 | |||
110 | export function foldConjunction(node: SyntaxNode): FoldRange | null { | ||
111 | if (node.parent?.type?.name === 'PredicateBody') { | ||
112 | return foldWithSibling(node); | ||
113 | } | ||
114 | return foldWholeNode(node); | ||
115 | } | ||