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import { ParserState, Context } from '../common';
import { Token, descKeywordTable } from '../token';
import { Chars } from '../chars';
import { advanceChar, consumeMultiUnitCodePoint, fromCodePoint, toHex } from './common';
import { CharTypes, CharFlags, isIdentifierPart, isIdentifierStart, isIdPart } from './charClassifier';
import { report, reportScannerError, Errors } from '../errors';
/**
* Scans identifier
*
* @param parser Parser object
* @param context Context masks
*/
export function scanIdentifier(parser: ParserState, context: Context, isValidAsKeyword: 0 | 1): Token {
while (isIdPart[advanceChar(parser)]) {}
parser.tokenValue = parser.source.slice(parser.tokenPos, parser.index);
return parser.currentChar !== Chars.Backslash && parser.currentChar < 0x7e
? descKeywordTable[parser.tokenValue] || Token.Identifier
: scanIdentifierSlowCase(parser, context, 0, isValidAsKeyword);
}
/**
* Scans unicode identifier
*
* @param parser Parser object
* @param context Context masks
*/
export function scanUnicodeIdentifier(parser: ParserState, context: Context): Token {
const cookedChar = scanIdentifierUnicodeEscape(parser);
if (!isIdentifierPart(cookedChar)) report(parser, Errors.InvalidUnicodeEscapeSequence);
parser.tokenValue = fromCodePoint(cookedChar);
return scanIdentifierSlowCase(parser, context, /* hasEscape */ 1, CharTypes[cookedChar] & CharFlags.KeywordCandidate);
}
/**
* Scans identifier slow case
*
* @param parser Parser object
* @param context Context masks
* @param hasEscape True if contains a unicode sequence
* @param isValidAsKeyword
*/
export function scanIdentifierSlowCase(
parser: ParserState,
context: Context,
hasEscape: 0 | 1,
isValidAsKeyword: number
): Token {
let start = parser.index;
while (parser.index < parser.end) {
if (parser.currentChar === Chars.Backslash) {
parser.tokenValue += parser.source.slice(start, parser.index);
hasEscape = 1;
const code = scanIdentifierUnicodeEscape(parser);
if (!isIdentifierPart(code)) report(parser, Errors.InvalidUnicodeEscapeSequence);
isValidAsKeyword = isValidAsKeyword && CharTypes[code] & CharFlags.KeywordCandidate;
parser.tokenValue += fromCodePoint(code);
start = parser.index;
} else if (isIdentifierPart(parser.currentChar) || consumeMultiUnitCodePoint(parser, parser.currentChar)) {
advanceChar(parser);
} else {
break;
}
}
if (parser.index <= parser.end) {
parser.tokenValue += parser.source.slice(start, parser.index);
}
const length = parser.tokenValue.length;
if (isValidAsKeyword && length >= 2 && length <= 11) {
const token: Token | undefined = descKeywordTable[parser.tokenValue];
if (token === void 0) return Token.Identifier;
if (!hasEscape) return token;
if (context & Context.Strict) {
return token === Token.AwaitKeyword && (context & (Context.Module | Context.InAwaitContext)) === 0
? token
: token === Token.StaticKeyword
? Token.EscapedFutureReserved
: (token & Token.FutureReserved) === Token.FutureReserved
? Token.EscapedFutureReserved
: Token.EscapedReserved;
}
if (
context & Context.AllowEscapedKeyword &&
(context & Context.InGlobal) === 0 &&
(token & Token.Reserved) === Token.Reserved
)
return token;
if (token === Token.YieldKeyword) {
return context & Context.AllowEscapedKeyword
? Token.AnyIdentifier
: context & Context.InYieldContext
? Token.EscapedReserved
: token;
}
return token === Token.AsyncKeyword && context & Context.AllowEscapedKeyword
? Token.AnyIdentifier
: (token & Token.FutureReserved) === Token.FutureReserved
? token
: token === Token.AwaitKeyword && (context & Context.InAwaitContext) === 0
? token
: Token.EscapedReserved;
}
return Token.Identifier;
}
/**
* Scans private name
*
* @param parser Parser object
*/
export function scanPrivateIdentifier(parser: ParserState): Token {
if (!isIdentifierStart(advanceChar(parser))) report(parser, Errors.MissingPrivateIdentifier);
return Token.PrivateField;
}
/**
* Scans unicode identifier
*
* @param parser Parser object
*/
export function scanIdentifierUnicodeEscape(parser: ParserState): number {
// Check for Unicode escape of the form '\uXXXX'
// and return code point value if valid Unicode escape is found.
if (parser.source.charCodeAt(parser.index + 1) !== Chars.LowerU) {
report(parser, Errors.InvalidUnicodeEscapeSequence);
}
parser.currentChar = parser.source.charCodeAt((parser.index += 2));
return scanUnicodeEscape(parser);
}
/**
* Scans unicode escape value
*
* @param parser Parser object
*/
export function scanUnicodeEscape(parser: ParserState): number {
// Accept both \uxxxx and \u{xxxxxx}
let codePoint = 0;
const char = parser.currentChar;
// First handle a delimited Unicode escape, e.g. \u{1F4A9}
if (char === Chars.LeftBrace) {
const begin = parser.index - 2;
while (CharTypes[advanceChar(parser)] & CharFlags.Hex) {
codePoint = (codePoint << 4) | toHex(parser.currentChar);
if (codePoint > Chars.NonBMPMax) reportScannerError(begin, parser.line, parser.index + 1, Errors.UnicodeOverflow);
}
// At least 4 characters have to be read
if ((parser.currentChar as number) !== Chars.RightBrace) {
reportScannerError(begin, parser.line, parser.index - 1, Errors.InvalidHexEscapeSequence);
}
advanceChar(parser); // consumes '}'
return codePoint;
}
if ((CharTypes[char] & CharFlags.Hex) === 0) report(parser, Errors.InvalidHexEscapeSequence); // first one is mandatory
const char2 = parser.source.charCodeAt(parser.index + 1);
if ((CharTypes[char2] & CharFlags.Hex) === 0) report(parser, Errors.InvalidHexEscapeSequence);
const char3 = parser.source.charCodeAt(parser.index + 2);
if ((CharTypes[char3] & CharFlags.Hex) === 0) report(parser, Errors.InvalidHexEscapeSequence);
const char4 = parser.source.charCodeAt(parser.index + 3);
if ((CharTypes[char4] & CharFlags.Hex) === 0) report(parser, Errors.InvalidHexEscapeSequence);
codePoint = (toHex(char) << 12) | (toHex(char2) << 8) | (toHex(char3) << 4) | toHex(char4);
parser.currentChar = parser.source.charCodeAt((parser.index += 4));
return codePoint;
}
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