Function isEscapedAt

packages/queryLanguage/src/tokens.ts:133–143

* Checks whether the character at the given offset is escaped by an odd number * of immediately preceding backslashes.

(input: InputStream, offset: number)

 * of immediately preceding backslashes.
 */
function isEscapedAt(input: InputStream, offset: number): boolean {
    let backslashCount = 0;
    let currentOffset = offset - 1;

    while (input.peek(currentOffset) === 92 /* backslash */) {
        backslashCount++;
        currentOffset--;
    }

    return backslashCount % 2 === 1;
}

/**
 * Returns the offset of the closing ')' that matches the '(' at startOffset.