babel/src/location.js

67 lines
1.7 KiB
JavaScript
Executable File

import { Parser } from "./state";
import { lineBreakG } from "./whitespace";
// These are used when `options.locations` is on, for the
// `startLoc` and `endLoc` properties.
export class Position {
constructor(line, col) {
this.line = line;
this.column = col;
}
offset(n) {
return new Position(this.line, this.column + n);
}
}
export class SourceLocation {
constructor(start, end) {
this.start = start;
this.end = end;
}
}
// The `getLineInfo` function is mostly useful when the
// `locations` option is off (for performance reasons) and you
// want to find the line/column position for a given character
// offset. `input` should be the code string that the offset refers
// into.
export function getLineInfo(input, offset) {
for (let line = 1, cur = 0; ;) {
lineBreakG.lastIndex = cur;
let match = lineBreakG.exec(input);
if (match && match.index < offset) {
++line;
cur = match.index + match[0].length;
} else {
return new Position(line, offset - cur);
}
}
}
const pp = Parser.prototype;
// This function is used to raise exceptions on parse errors. It
// takes an offset integer (into the current `input`) to indicate
// the location of the error, attaches the position to the end
// of the error message, and then raises a `SyntaxError` with that
// message.
pp.raise = function (pos, message) {
let loc = getLineInfo(this.input, pos);
message += ` (${loc.line}:${loc.column})`;
let err = new SyntaxError(message);
err.pos = pos;
err.loc = loc;
err.raisedAt = this.pos;
throw err;
};
pp.curPosition = function () {
if (this.options.locations) {
return new Position(this.curLine, this.pos - this.lineStart);
}
};