/
Parser.cpp
2846 lines (2199 loc) · 86.9 KB
/
Parser.cpp
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// This file is part of the Luau programming language and is licensed under MIT License; see LICENSE.txt for details
#include "Luau/Parser.h"
#include "Luau/TimeTrace.h"
#include <algorithm>
// Warning: If you are introducing new syntax, ensure that it is behind a separate
// flag so that we don't break production games by reverting syntax changes.
// See docs/SyntaxChanges.md for an explanation.
LUAU_FASTINTVARIABLE(LuauRecursionLimit, 1000)
LUAU_FASTINTVARIABLE(LuauParseErrorLimit, 100)
LUAU_FASTFLAGVARIABLE(LuauFixAmbiguousErrorRecoveryInAssign, false)
LUAU_FASTFLAGVARIABLE(LuauParseSingletonTypes, false)
LUAU_FASTFLAGVARIABLE(LuauParseTypeAliasDefaults, false)
LUAU_FASTFLAGVARIABLE(LuauParseRecoverTypePackEllipsis, false)
LUAU_FASTFLAGVARIABLE(LuauStartingBrokenComment, false)
namespace Luau
{
inline bool isSpace(char ch)
{
return ch == ' ' || ch == '\t' || ch == '\r' || ch == '\n' || ch == '\v' || ch == '\f';
}
static bool isComment(const Lexeme& lexeme)
{
return lexeme.type == Lexeme::Comment || lexeme.type == Lexeme::BlockComment;
}
ParseError::ParseError(const Location& location, const std::string& message)
: location(location)
, message(message)
{
}
const char* ParseError::what() const throw()
{
return message.c_str();
}
const Location& ParseError::getLocation() const
{
return location;
}
const std::string& ParseError::getMessage() const
{
return message;
}
// LUAU_NOINLINE is used to limit the stack cost of this function due to std::string object / exception plumbing
LUAU_NOINLINE void ParseError::raise(const Location& location, const char* format, ...)
{
va_list args;
va_start(args, format);
std::string message = vformat(format, args);
va_end(args);
throw ParseError(location, message);
}
ParseErrors::ParseErrors(std::vector<ParseError> errors)
: errors(std::move(errors))
{
LUAU_ASSERT(!this->errors.empty());
if (this->errors.size() == 1)
message = this->errors.front().what();
else
message = format("%d parse errors", int(this->errors.size()));
}
const char* ParseErrors::what() const throw()
{
return message.c_str();
}
const std::vector<ParseError>& ParseErrors::getErrors() const
{
return errors;
}
template<typename T>
TempVector<T>::TempVector(std::vector<T>& storage)
: storage(storage)
, offset(storage.size())
, size_(0)
{
}
template<typename T>
TempVector<T>::~TempVector()
{
LUAU_ASSERT(storage.size() == offset + size_);
storage.erase(storage.begin() + offset, storage.end());
}
template<typename T>
const T& TempVector<T>::operator[](size_t index) const
{
LUAU_ASSERT(index < size_);
return storage[offset + index];
}
template<typename T>
const T& TempVector<T>::front() const
{
LUAU_ASSERT(size_ > 0);
return storage[offset];
}
template<typename T>
const T& TempVector<T>::back() const
{
LUAU_ASSERT(size_ > 0);
return storage.back();
}
template<typename T>
bool TempVector<T>::empty() const
{
return size_ == 0;
}
template<typename T>
size_t TempVector<T>::size() const
{
return size_;
}
template<typename T>
void TempVector<T>::push_back(const T& item)
{
LUAU_ASSERT(storage.size() == offset + size_);
storage.push_back(item);
size_++;
}
static bool shouldParseTypePackAnnotation(Lexer& lexer)
{
if (lexer.current().type == Lexeme::Dot3)
return true;
else if (lexer.current().type == Lexeme::Name && lexer.lookahead().type == Lexeme::Dot3)
return true;
return false;
}
ParseResult Parser::parse(const char* buffer, size_t bufferSize, AstNameTable& names, Allocator& allocator, ParseOptions options)
{
LUAU_TIMETRACE_SCOPE("Parser::parse", "Parser");
Parser p(buffer, bufferSize, names, allocator);
try
{
std::vector<std::string> hotcomments;
while (isComment(p.lexer.current()) || p.lexer.current().type == Lexeme::BrokenComment)
{
const char* text = p.lexer.current().data;
unsigned int length = p.lexer.current().length;
if (length && text[0] == '!')
{
unsigned int end = length;
while (end > 0 && isSpace(text[end - 1]))
--end;
hotcomments.push_back(std::string(text + 1, text + end));
}
const Lexeme::Type type = p.lexer.current().type;
const Location loc = p.lexer.current().location;
if (FFlag::LuauStartingBrokenComment)
{
if (options.captureComments)
p.commentLocations.push_back(Comment{type, loc});
if (type == Lexeme::BrokenComment)
break;
p.lexer.next();
}
else
{
p.lexer.next();
if (options.captureComments)
p.commentLocations.push_back(Comment{type, loc});
}
}
p.lexer.setSkipComments(true);
p.options = options;
AstStatBlock* root = p.parseChunk();
return ParseResult{root, hotcomments, p.parseErrors, std::move(p.commentLocations)};
}
catch (ParseError& err)
{
// when catching a fatal error, append it to the list of non-fatal errors and return
p.parseErrors.push_back(err);
return ParseResult{nullptr, {}, p.parseErrors};
}
}
Parser::Parser(const char* buffer, size_t bufferSize, AstNameTable& names, Allocator& allocator)
: lexer(buffer, bufferSize, names)
, allocator(allocator)
, recursionCounter(0)
, endMismatchSuspect(Location(), Lexeme::Eof)
, localMap(AstName())
{
Function top;
top.vararg = true;
functionStack.push_back(top);
nameSelf = names.addStatic("self");
nameNumber = names.addStatic("number");
nameError = names.addStatic(errorName);
nameNil = names.getOrAdd("nil"); // nil is a reserved keyword
matchRecoveryStopOnToken.assign(Lexeme::Type::Reserved_END, 0);
matchRecoveryStopOnToken[Lexeme::Type::Eof] = 1;
// read first lexeme
nextLexeme();
}
bool Parser::blockFollow(const Lexeme& l)
{
return l.type == Lexeme::Eof || l.type == Lexeme::ReservedElse || l.type == Lexeme::ReservedElseif || l.type == Lexeme::ReservedEnd ||
l.type == Lexeme::ReservedUntil;
}
AstStatBlock* Parser::parseChunk()
{
AstStatBlock* result = parseBlock();
if (lexer.current().type != Lexeme::Eof)
expectAndConsumeFail(Lexeme::Eof, nullptr);
return result;
}
// chunk ::= {stat [`;']} [laststat [`;']]
// block ::= chunk
AstStatBlock* Parser::parseBlock()
{
unsigned int localsBegin = saveLocals();
AstStatBlock* result = parseBlockNoScope();
restoreLocals(localsBegin);
return result;
}
static bool isStatLast(AstStat* stat)
{
return stat->is<AstStatBreak>() || stat->is<AstStatContinue>() || stat->is<AstStatReturn>();
}
AstStatBlock* Parser::parseBlockNoScope()
{
TempVector<AstStat*> body(scratchStat);
const Position prevPosition = lexer.previousLocation().end;
while (!blockFollow(lexer.current()))
{
unsigned int recursionCounterOld = recursionCounter;
incrementRecursionCounter("block");
AstStat* stat = parseStat();
recursionCounter = recursionCounterOld;
if (lexer.current().type == ';')
{
nextLexeme();
stat->hasSemicolon = true;
}
body.push_back(stat);
if (isStatLast(stat))
break;
}
const Location location = Location(prevPosition, lexer.current().location.begin);
return allocator.alloc<AstStatBlock>(location, copy(body));
}
// stat ::=
// varlist `=' explist |
// functioncall |
// do block end |
// while exp do block end |
// repeat block until exp |
// if exp then block {elseif exp then block} [else block] end |
// for binding `=' exp `,' exp [`,' exp] do block end |
// for namelist in explist do block end |
// function funcname funcbody |
// local function Name funcbody |
// local namelist [`=' explist]
// laststat ::= return [explist] | break
AstStat* Parser::parseStat()
{
// guess the type from the token type
switch (lexer.current().type)
{
case Lexeme::ReservedIf:
return parseIf();
case Lexeme::ReservedWhile:
return parseWhile();
case Lexeme::ReservedDo:
return parseDo();
case Lexeme::ReservedFor:
return parseFor();
case Lexeme::ReservedRepeat:
return parseRepeat();
case Lexeme::ReservedFunction:
return parseFunctionStat();
case Lexeme::ReservedLocal:
return parseLocal();
case Lexeme::ReservedReturn:
return parseReturn();
case Lexeme::ReservedBreak:
return parseBreak();
default:;
}
Location start = lexer.current().location;
// we need to disambiguate a few cases, primarily assignment (lvalue = ...) vs statements-that-are calls
AstExpr* expr = parsePrimaryExpr(/* asStatement= */ true);
if (expr->is<AstExprCall>())
return allocator.alloc<AstStatExpr>(expr->location, expr);
// if the next token is , or =, it's an assignment (, means it's an assignment with multiple variables)
if (lexer.current().type == ',' || lexer.current().type == '=')
return parseAssignment(expr);
// if the next token is a compound assignment operator, it's a compound assignment (these don't support multiple variables)
if (std::optional<AstExprBinary::Op> op = parseCompoundOp(lexer.current()))
return parseCompoundAssignment(expr, *op);
// we know this isn't a call or an assignment; therefore it must be a context-sensitive keyword such as `type` or `continue`
AstName ident = getIdentifier(expr);
if (options.allowTypeAnnotations)
{
if (ident == "type")
return parseTypeAlias(expr->location, /* exported =*/false);
if (ident == "export" && lexer.current().type == Lexeme::Name && AstName(lexer.current().name) == "type")
{
nextLexeme();
return parseTypeAlias(expr->location, /* exported =*/true);
}
}
if (options.supportContinueStatement && ident == "continue")
return parseContinue(expr->location);
if (options.allowTypeAnnotations && options.allowDeclarationSyntax)
{
if (ident == "declare")
return parseDeclaration(expr->location);
}
// skip unexpected symbol if lexer couldn't advance at all (statements are parsed in a loop)
if (start == lexer.current().location)
nextLexeme();
return reportStatError(expr->location, copy({expr}), {}, "Incomplete statement: expected assignment or a function call");
}
// if exp then block {elseif exp then block} [else block] end
AstStat* Parser::parseIf()
{
Location start = lexer.current().location;
nextLexeme(); // if / elseif
AstExpr* cond = parseExpr();
Lexeme matchThen = lexer.current();
bool hasThen = expectAndConsume(Lexeme::ReservedThen, "if statement");
AstStatBlock* thenbody = parseBlock();
AstStat* elsebody = nullptr;
Location end = start;
std::optional<Location> elseLocation;
bool hasEnd = false;
if (lexer.current().type == Lexeme::ReservedElseif)
{
unsigned int recursionCounterOld = recursionCounter;
incrementRecursionCounter("elseif");
elseLocation = lexer.current().location;
elsebody = parseIf();
end = elsebody->location;
hasEnd = elsebody->as<AstStatIf>()->hasEnd;
recursionCounter = recursionCounterOld;
}
else
{
Lexeme matchThenElse = matchThen;
if (lexer.current().type == Lexeme::ReservedElse)
{
elseLocation = lexer.current().location;
matchThenElse = lexer.current();
nextLexeme();
elsebody = parseBlock();
elsebody->location.begin = matchThenElse.location.end;
}
end = lexer.current().location;
hasEnd = expectMatchEndAndConsume(Lexeme::ReservedEnd, matchThenElse);
}
return allocator.alloc<AstStatIf>(Location(start, end), cond, thenbody, elsebody, hasThen, matchThen.location, elseLocation, hasEnd);
}
// while exp do block end
AstStat* Parser::parseWhile()
{
Location start = lexer.current().location;
nextLexeme(); // while
AstExpr* cond = parseExpr();
Lexeme matchDo = lexer.current();
bool hasDo = expectAndConsume(Lexeme::ReservedDo, "while loop");
functionStack.back().loopDepth++;
AstStatBlock* body = parseBlock();
functionStack.back().loopDepth--;
Location end = lexer.current().location;
bool hasEnd = expectMatchEndAndConsume(Lexeme::ReservedEnd, matchDo);
return allocator.alloc<AstStatWhile>(Location(start, end), cond, body, hasDo, matchDo.location, hasEnd);
}
// repeat block until exp
AstStat* Parser::parseRepeat()
{
Location start = lexer.current().location;
Lexeme matchRepeat = lexer.current();
nextLexeme(); // repeat
unsigned int localsBegin = saveLocals();
functionStack.back().loopDepth++;
AstStatBlock* body = parseBlockNoScope();
functionStack.back().loopDepth--;
bool hasUntil = expectMatchEndAndConsume(Lexeme::ReservedUntil, matchRepeat);
AstExpr* cond = parseExpr();
restoreLocals(localsBegin);
return allocator.alloc<AstStatRepeat>(Location(start, cond->location), cond, body, hasUntil);
}
// do block end
AstStat* Parser::parseDo()
{
Location start = lexer.current().location;
Lexeme matchDo = lexer.current();
nextLexeme(); // do
AstStat* body = parseBlock();
body->location.begin = start.begin;
expectMatchEndAndConsume(Lexeme::ReservedEnd, matchDo);
return body;
}
// break
AstStat* Parser::parseBreak()
{
Location start = lexer.current().location;
nextLexeme(); // break
if (functionStack.back().loopDepth == 0)
return reportStatError(start, {}, copy<AstStat*>({allocator.alloc<AstStatBreak>(start)}), "break statement must be inside a loop");
return allocator.alloc<AstStatBreak>(start);
}
// continue
AstStat* Parser::parseContinue(const Location& start)
{
if (functionStack.back().loopDepth == 0)
return reportStatError(start, {}, copy<AstStat*>({allocator.alloc<AstStatContinue>(start)}), "continue statement must be inside a loop");
// note: the token is already parsed for us!
return allocator.alloc<AstStatContinue>(start);
}
// for binding `=' exp `,' exp [`,' exp] do block end |
// for bindinglist in explist do block end |
AstStat* Parser::parseFor()
{
Location start = lexer.current().location;
nextLexeme(); // for
Binding varname = parseBinding();
if (lexer.current().type == '=')
{
nextLexeme();
AstExpr* from = parseExpr();
expectAndConsume(',', "index range");
AstExpr* to = parseExpr();
AstExpr* step = nullptr;
if (lexer.current().type == ',')
{
nextLexeme();
step = parseExpr();
}
Lexeme matchDo = lexer.current();
bool hasDo = expectAndConsume(Lexeme::ReservedDo, "for loop");
unsigned int localsBegin = saveLocals();
functionStack.back().loopDepth++;
AstLocal* var = pushLocal(varname);
AstStatBlock* body = parseBlock();
functionStack.back().loopDepth--;
restoreLocals(localsBegin);
Location end = lexer.current().location;
bool hasEnd = expectMatchEndAndConsume(Lexeme::ReservedEnd, matchDo);
return allocator.alloc<AstStatFor>(Location(start, end), var, from, to, step, body, hasDo, matchDo.location, hasEnd);
}
else
{
TempVector<Binding> names(scratchBinding);
names.push_back(varname);
if (lexer.current().type == ',')
{
nextLexeme();
parseBindingList(names);
}
Location inLocation = lexer.current().location;
bool hasIn = expectAndConsume(Lexeme::ReservedIn, "for loop");
TempVector<AstExpr*> values(scratchExpr);
parseExprList(values);
Lexeme matchDo = lexer.current();
bool hasDo = expectAndConsume(Lexeme::ReservedDo, "for loop");
unsigned int localsBegin = saveLocals();
functionStack.back().loopDepth++;
TempVector<AstLocal*> vars(scratchLocal);
for (size_t i = 0; i < names.size(); ++i)
vars.push_back(pushLocal(names[i]));
AstStatBlock* body = parseBlock();
functionStack.back().loopDepth--;
restoreLocals(localsBegin);
Location end = lexer.current().location;
bool hasEnd = expectMatchEndAndConsume(Lexeme::ReservedEnd, matchDo);
return allocator.alloc<AstStatForIn>(
Location(start, end), copy(vars), copy(values), body, hasIn, inLocation, hasDo, matchDo.location, hasEnd);
}
}
// function funcname funcbody |
// funcname ::= Name {`.' Name} [`:' Name]
AstStat* Parser::parseFunctionStat()
{
Location start = lexer.current().location;
Lexeme matchFunction = lexer.current();
nextLexeme();
AstName debugname = (lexer.current().type == Lexeme::Name) ? AstName(lexer.current().name) : AstName();
// parse funcname into a chain of indexing operators
AstExpr* expr = parseNameExpr("function name");
unsigned int recursionCounterOld = recursionCounter;
while (lexer.current().type == '.')
{
Position opPosition = lexer.current().location.begin;
nextLexeme();
Name name = parseName("field name");
// while we could concatenate the name chain, for now let's just write the short name
debugname = name.name;
expr = allocator.alloc<AstExprIndexName>(Location(start, name.location), expr, name.name, name.location, opPosition, '.');
// note: while the parser isn't recursive here, we're generating recursive structures of unbounded depth
incrementRecursionCounter("function name");
}
recursionCounter = recursionCounterOld;
// finish with :
bool hasself = false;
if (lexer.current().type == ':')
{
Position opPosition = lexer.current().location.begin;
nextLexeme();
Name name = parseName("method name");
// while we could concatenate the name chain, for now let's just write the short name
debugname = name.name;
expr = allocator.alloc<AstExprIndexName>(Location(start, name.location), expr, name.name, name.location, opPosition, ':');
hasself = true;
}
matchRecoveryStopOnToken[Lexeme::ReservedEnd]++;
AstExprFunction* body = parseFunctionBody(hasself, matchFunction, debugname, {}).first;
matchRecoveryStopOnToken[Lexeme::ReservedEnd]--;
return allocator.alloc<AstStatFunction>(Location(start, body->location), expr, body);
}
// local function Name funcbody |
// local bindinglist [`=' explist]
AstStat* Parser::parseLocal()
{
Location start = lexer.current().location;
nextLexeme(); // local
if (lexer.current().type == Lexeme::ReservedFunction)
{
Lexeme matchFunction = lexer.current();
nextLexeme();
// matchFunction is only used for diagnostics; to make it suitable for detecting missed indentation between
// `local function` and `end`, we patch the token to begin at the column where `local` starts
if (matchFunction.location.begin.line == start.begin.line)
matchFunction.location.begin.column = start.begin.column;
Name name = parseName("variable name");
matchRecoveryStopOnToken[Lexeme::ReservedEnd]++;
auto [body, var] = parseFunctionBody(false, matchFunction, name.name, name);
matchRecoveryStopOnToken[Lexeme::ReservedEnd]--;
Location location{start.begin, body->location.end};
return allocator.alloc<AstStatLocalFunction>(location, var, body);
}
else
{
matchRecoveryStopOnToken['=']++;
TempVector<Binding> names(scratchBinding);
parseBindingList(names);
matchRecoveryStopOnToken['=']--;
TempVector<AstLocal*> vars(scratchLocal);
TempVector<AstExpr*> values(scratchExpr);
std::optional<Location> equalsSignLocation;
if (lexer.current().type == '=')
{
equalsSignLocation = lexer.current().location;
nextLexeme();
parseExprList(values);
}
for (size_t i = 0; i < names.size(); ++i)
vars.push_back(pushLocal(names[i]));
Location end = values.empty() ? lexer.previousLocation() : values.back()->location;
return allocator.alloc<AstStatLocal>(Location(start, end), copy(vars), copy(values), equalsSignLocation);
}
}
// return [explist]
AstStat* Parser::parseReturn()
{
Location start = lexer.current().location;
nextLexeme();
TempVector<AstExpr*> list(scratchExpr);
if (!blockFollow(lexer.current()) && lexer.current().type != ';')
parseExprList(list);
Location end = list.empty() ? start : list.back()->location;
return allocator.alloc<AstStatReturn>(Location(start, end), copy(list));
}
// type Name [`<' varlist `>'] `=' typeannotation
AstStat* Parser::parseTypeAlias(const Location& start, bool exported)
{
// note: `type` token is already parsed for us, so we just need to parse the rest
auto name = parseNameOpt("type name");
// Use error name if the name is missing
if (!name)
name = Name(nameError, lexer.current().location);
auto [generics, genericPacks] = parseGenericTypeList(/* withDefaultValues= */ FFlag::LuauParseTypeAliasDefaults);
expectAndConsume('=', "type alias");
AstType* type = parseTypeAnnotation();
return allocator.alloc<AstStatTypeAlias>(Location(start, type->location), name->name, generics, genericPacks, type, exported);
}
AstDeclaredClassProp Parser::parseDeclaredClassMethod()
{
nextLexeme();
Location start = lexer.current().location;
Name fnName = parseName("function name");
// TODO: generic method declarations CLI-39909
AstArray<AstGenericType> generics;
AstArray<AstGenericTypePack> genericPacks;
generics.size = 0;
generics.data = nullptr;
genericPacks.size = 0;
genericPacks.data = nullptr;
Lexeme matchParen = lexer.current();
expectAndConsume('(', "function parameter list start");
TempVector<Binding> args(scratchBinding);
std::optional<Location> vararg = std::nullopt;
AstTypePack* varargAnnotation = nullptr;
if (lexer.current().type != ')')
std::tie(vararg, varargAnnotation) = parseBindingList(args, /* allowDot3 */ true);
expectMatchAndConsume(')', matchParen);
AstTypeList retTypes = parseOptionalReturnTypeAnnotation().value_or(AstTypeList{copy<AstType*>(nullptr, 0), nullptr});
Location end = lexer.current().location;
TempVector<AstType*> vars(scratchAnnotation);
TempVector<std::optional<AstArgumentName>> varNames(scratchOptArgName);
if (args.size() == 0 || args[0].name.name != "self" || args[0].annotation != nullptr)
{
return AstDeclaredClassProp{fnName.name,
reportTypeAnnotationError(Location(start, end), {}, /*isMissing*/ false, "'self' must be present as the unannotated first parameter"),
true};
}
// Skip the first index.
for (size_t i = 1; i < args.size(); ++i)
{
varNames.push_back(AstArgumentName{args[i].name.name, args[i].name.location});
if (args[i].annotation)
vars.push_back(args[i].annotation);
else
vars.push_back(reportTypeAnnotationError(
Location(start, end), {}, /*isMissing*/ false, "All declaration parameters aside from 'self' must be annotated"));
}
if (vararg && !varargAnnotation)
report(start, "All declaration parameters aside from 'self' must be annotated");
AstType* fnType = allocator.alloc<AstTypeFunction>(
Location(start, end), generics, genericPacks, AstTypeList{copy(vars), varargAnnotation}, copy(varNames), retTypes);
return AstDeclaredClassProp{fnName.name, fnType, true};
}
AstStat* Parser::parseDeclaration(const Location& start)
{
// `declare` token is already parsed at this point
if (lexer.current().type == Lexeme::ReservedFunction)
{
nextLexeme();
Name globalName = parseName("global function name");
auto [generics, genericPacks] = parseGenericTypeList(/* withDefaultValues= */ false);
Lexeme matchParen = lexer.current();
expectAndConsume('(', "global function declaration");
TempVector<Binding> args(scratchBinding);
std::optional<Location> vararg;
AstTypePack* varargAnnotation = nullptr;
if (lexer.current().type != ')')
std::tie(vararg, varargAnnotation) = parseBindingList(args, /* allowDot3= */ true);
expectMatchAndConsume(')', matchParen);
AstTypeList retTypes = parseOptionalReturnTypeAnnotation().value_or(AstTypeList{copy<AstType*>(nullptr, 0)});
Location end = lexer.current().location;
TempVector<AstType*> vars(scratchAnnotation);
TempVector<AstArgumentName> varNames(scratchArgName);
for (size_t i = 0; i < args.size(); ++i)
{
if (!args[i].annotation)
return reportStatError(Location(start, end), {}, {}, "All declaration parameters must be annotated");
vars.push_back(args[i].annotation);
varNames.push_back({args[i].name.name, args[i].name.location});
}
if (vararg && !varargAnnotation)
return reportStatError(Location(start, end), {}, {}, "All declaration parameters must be annotated");
return allocator.alloc<AstStatDeclareFunction>(
Location(start, end), globalName.name, generics, genericPacks, AstTypeList{copy(vars), varargAnnotation}, copy(varNames), retTypes);
}
else if (AstName(lexer.current().name) == "class")
{
nextLexeme();
Location classStart = lexer.current().location;
Name className = parseName("class name");
std::optional<AstName> superName = std::nullopt;
if (AstName(lexer.current().name) == "extends")
{
nextLexeme();
superName = parseName("superclass name").name;
}
TempVector<AstDeclaredClassProp> props(scratchDeclaredClassProps);
while (lexer.current().type != Lexeme::ReservedEnd)
{
// There are two possibilities: Either it's a property or a function.
if (lexer.current().type == Lexeme::ReservedFunction)
{
props.push_back(parseDeclaredClassMethod());
}
else
{
Name propName = parseName("property name");
expectAndConsume(':', "property type annotation");
AstType* propType = parseTypeAnnotation();
props.push_back(AstDeclaredClassProp{propName.name, propType, false});
}
}
Location classEnd = lexer.current().location;
nextLexeme(); // skip past `end`
return allocator.alloc<AstStatDeclareClass>(Location(classStart, classEnd), className.name, superName, copy(props));
}
else if (auto globalName = parseNameOpt("global variable name"))
{
expectAndConsume(':', "global variable declaration");
AstType* type = parseTypeAnnotation();
return allocator.alloc<AstStatDeclareGlobal>(Location(start, type->location), globalName->name, type);
}
else
{
return reportStatError(start, {}, {}, "declare must be followed by an identifier, 'function', or 'class'");
}
}
static bool isExprLValue(AstExpr* expr)
{
return expr->is<AstExprLocal>() || expr->is<AstExprGlobal>() || expr->is<AstExprIndexExpr>() || expr->is<AstExprIndexName>();
}
// varlist `=' explist
AstStat* Parser::parseAssignment(AstExpr* initial)
{
if (!isExprLValue(initial))
initial = reportExprError(initial->location, copy({initial}), "Assigned expression must be a variable or a field");
TempVector<AstExpr*> vars(scratchExpr);
vars.push_back(initial);
while (lexer.current().type == ',')
{
nextLexeme();
AstExpr* expr = parsePrimaryExpr(/* asStatement= */ FFlag::LuauFixAmbiguousErrorRecoveryInAssign);
if (!isExprLValue(expr))
expr = reportExprError(expr->location, copy({expr}), "Assigned expression must be a variable or a field");
vars.push_back(expr);
}
expectAndConsume('=', "assignment");
TempVector<AstExpr*> values(scratchExprAux);
parseExprList(values);
return allocator.alloc<AstStatAssign>(Location(initial->location, values.back()->location), copy(vars), copy(values));
}
// var [`+=' | `-=' | `*=' | `/=' | `%=' | `^=' | `..='] exp
AstStat* Parser::parseCompoundAssignment(AstExpr* initial, AstExprBinary::Op op)
{
if (!isExprLValue(initial))
{
initial = reportExprError(initial->location, copy({initial}), "Assigned expression must be a variable or a field");
}
nextLexeme();
AstExpr* value = parseExpr();
return allocator.alloc<AstStatCompoundAssign>(Location(initial->location, value->location), op, initial, value);
}
// funcbody ::= `(' [parlist] `)' [`:' ReturnType] block end
// parlist ::= bindinglist [`,' `...'] | `...'
std::pair<AstExprFunction*, AstLocal*> Parser::parseFunctionBody(
bool hasself, const Lexeme& matchFunction, const AstName& debugname, std::optional<Name> localName)
{
Location start = matchFunction.location;
auto [generics, genericPacks] = parseGenericTypeList(/* withDefaultValues= */ false);
Lexeme matchParen = lexer.current();