41 lines
1.5 KiB
TypeScript
41 lines
1.5 KiB
TypeScript
 
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import { StateEffect, StateField, type Extension, type Text } from "@codemirror/state";
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import { Decoration, EditorView, type DecorationSet } from "@codemirror/view";
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export const setHighlight = StateEffect.define<{ from: number; to: number } | null>();
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const lineMark = Decoration.line({ class: "cm-triple-c-target" });
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export function lineRangeToPositions(doc: Text, from: number, to: number): { from: number; to: number } | null {
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const clamp = (n: number) => Math.min(Math.max(1, Math.floor(n)), doc.lines);
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const a = clamp(from);
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const b = Math.max(a, clamp(to));
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return { from: doc.line(a).from, to: doc.line(b).from };
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}
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export const highlightLineField = StateField.define<DecorationSet>({
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create: () => Decoration.none,
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update(value, tr) {
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let next = value.map(tr.changes);
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for (const e of tr.effects) {
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if (!e.is(setHighlight)) continue;
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if (e.value === null) { next = Decoration.none; continue; }
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const range = lineRangeToPositions(tr.state.doc, e.value.from, e.value.to);
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if (!range) { next = Decoration.none; continue; }
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const marks = [];
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for (let pos = range.from; pos <= range.to; ) {
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const line = tr.state.doc.lineAt(pos);
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marks.push(lineMark.range(line.from));
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if (line.to + 1 > tr.state.doc.length) break;
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pos = line.to + 1;
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}
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next = Decoration.set(marks, true);
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}
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return next;
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},
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provide: (f) => EditorView.decorations.from(f),
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});
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export function highlightExtension(): Extension {
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return [highlightLineField];
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}
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