54 lines
1.2 KiB
JavaScript
54 lines
1.2 KiB
JavaScript
// @flow
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import { lineBreakG } from "./whitespace";
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export type Pos = {
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start: number;
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}
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// These are used when `options.locations` is on, for the
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// `startLoc` and `endLoc` properties.
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export class Position {
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line: number;
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column: number;
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constructor(line: number, col: number) {
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this.line = line;
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this.column = col;
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}
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}
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export class SourceLocation {
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start: Position;
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end: Position;
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filename: string;
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constructor(start: Position, end?: Position) {
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this.start = start;
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// $FlowIgnore (may start as null, but initialized later)
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this.end = end;
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}
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}
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// The `getLineInfo` function is mostly useful when the
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// `locations` option is off (for performance reasons) and you
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// want to find the line/column position for a given character
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// offset. `input` should be the code string that the offset refers
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// into.
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export function getLineInfo(input: string, offset: number): Position {
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for (let line = 1, cur = 0; ;) {
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lineBreakG.lastIndex = cur;
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const match = lineBreakG.exec(input);
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if (match && match.index < offset) {
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++line;
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cur = match.index + match[0].length;
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} else {
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return new Position(line, offset - cur);
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}
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}
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// istanbul ignore next
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throw new Error("Unreachable");
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}
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