@1771technologies/lytenyte-pro/dist/expressions/lexer/tokenize/scan-string.js

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import { ExpressionError } from "../../errors/index.js";
import { isHexDigit } from "../predicates/is-hex-digit.js";
const MAX_CODE_POINT = 0x10ffff;
const HEX_CODE_POINT_SIZE = 5;
export function scanString(source, start) {
    const quote = source[start];
    let value = "";
    let i = start + 1;
    while (i < source.length && source[i] !== quote) {
        if (source[i] === "\\") {
            i++;
            const escaped = source[i];
            if (escaped === "n")
                value += "\n";
            else if (escaped === "t")
                value += "\t";
            else if (escaped === "r")
                value += "\r";
            else if (escaped === "\\")
                value += "\\";
            else if (escaped === "0")
                value += "\0";
            else if (escaped === "x") {
                const hex = source.slice(i + 1, i + 3);
                if (hex.length < 2 || !isHexDigit(hex[0]) || !isHexDigit(hex[1])) {
                    throw new ExpressionError("Invalid \\x escape", { source, start, end: i });
                }
                value += String.fromCharCode(parseInt(hex, 16));
                i += 3;
                continue;
            }
            else if (escaped === "u") {
                if (source[i + 1] === "{") {
                    i += 2;
                    let hex = "";
                    while (i < source.length && source[i] !== "}" && source[i] !== quote) {
                        if (!isHexDigit(source[i])) {
                            throw new ExpressionError("Invalid \\u escape: non-hex digit", {
                                source,
                                start,
                                end: i,
                            });
                        }
                        hex += source[i];
                        i++;
                    }
                    if (i >= source.length || source[i] !== "}") {
                        throw new ExpressionError("Invalid \\u escape: missing closing brace", {
                            source,
                            start,
                            end: i,
                        });
                    }
                    if (hex.length === 0) {
                        throw new ExpressionError("Invalid \\u escape: empty code point", {
                            source,
                            start,
                            end: i,
                        });
                    }
                    const codePoint = parseInt(hex, 16);
                    if (codePoint > MAX_CODE_POINT) {
                        throw new ExpressionError("Invalid \\u escape: code point out of range", {
                            source,
                            start,
                            end: i,
                        });
                    }
                    value += String.fromCodePoint(codePoint);
                    i++;
                    continue;
                }
                else {
                    const hex = source.slice(i + 1, i + HEX_CODE_POINT_SIZE);
                    if (hex.length < 4 || ![...hex].every(isHexDigit)) {
                        throw new ExpressionError("Invalid \\u escape", { source, start, end: i });
                    }
                    value += String.fromCharCode(parseInt(hex, 16));
                    i += HEX_CODE_POINT_SIZE;
                    continue;
                }
            }
            else {
                value += escaped;
            }
        }
        else {
            value += source[i];
        }
        i++;
    }
    if (i >= source.length) {
        throw new ExpressionError("Unterminated string", { source, start, end: i });
    }
    i++;
    // We keep the string literals in the token.
    return { value: quote + value + quote, end: i };
}