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2f3f6acf21c88a5214861b9323cb260a495bbf3a
swift-mirror/lib/Parse/ParseExpr.cpp
Doug Gregor 2f3f6acf21 Make "true" and "false" Boolean literal constants for the BooleanLiteralConvertible protocol. 
Introduce the new BooleanLiteralConvertible protocol for Boolean
literals. Take "true" and "false" as real keywords (which is most of the
reason for the testsuite churn). Make Bool BooleanLiteralConvertible
and the default Boolean literal type, and ObjCBool
BooleanLiteralConvertible. Fixes <rdar://problem/17405310> and the
recent regression that made ObjCBool not work with true/false.


Swift SVN r19728
2014-07-09 16:57:35 +00:00

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//===--- ParseExpr.cpp - Swift Language Parser for Expressions ------------===//
//
// This source file is part of the Swift.org open source project
//
// Copyright (c) 2014 - 2015 Apple Inc. and the Swift project authors
// Licensed under Apache License v2.0 with Runtime Library Exception
//
// See http://swift.org/LICENSE.txt for license information
// See http://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
//
//===----------------------------------------------------------------------===//
//
// Expression Parsing and AST Building
//
//===----------------------------------------------------------------------===//
#include "swift/Parse/Parser.h"
#include "swift/AST/DiagnosticsParse.h"
#include "swift/Parse/CodeCompletionCallbacks.h"
#include "swift/Parse/Lexer.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/ADT/Twine.h"
#include "swift/Basic/Fallthrough.h"
#include "llvm/Support/SaveAndRestore.h"
#include "llvm/Support/raw_ostream.h"
using namespace swift;
/// \brief Create an argument with a trailing closure, with (optionally)
/// the elements, names, and parentheses locations from an existing argument.
static Expr *createArgWithTrailingClosure(ASTContext &context,
SourceLoc leftParen,
ArrayRef<Expr *> elementsIn,
ArrayRef<Identifier> namesIn,
ArrayRef<SourceLoc> nameLocsIn,
SourceLoc rightParen,
Expr *closure) {
// If there are no elements, just build a parenthesized expression around
// the cosure.
if (elementsIn.empty()) {
return new (context) ParenExpr(leftParen, closure, rightParen,
/*hasTrailingClosure=*/true);
}
// Create the list of elements, and add the trailing closure to the end.
SmallVector<Expr *, 4> elements(elementsIn.begin(), elementsIn.end());
elements.push_back(closure);
SmallVector<Identifier, 4> names;
SmallVector<SourceLoc, 4> nameLocs;
if (!namesIn.empty()) {
names.append(namesIn.begin(), namesIn.end());
names.push_back(Identifier());
nameLocs.append(nameLocsIn.begin(), nameLocsIn.end());
nameLocs.push_back(SourceLoc());
}
// Form a full tuple expression.
return TupleExpr::create(context, leftParen, elements, names, nameLocs,
rightParen, /*hasTrailingClosure=*/true,
/*Implicit=*/false);
}
/// \brief Add the given trailing closure argument to the call argument.
static Expr *addTrailingClosureToArgument(ASTContext &context,
Expr *arg, Expr *closure) {
// Deconstruct the call argument to find its elements, element names,
// and the locations of the left and right parentheses.
if (auto tuple = dyn_cast<TupleExpr>(arg)) {
// Deconstruct a tuple expression.
return createArgWithTrailingClosure(context,
tuple->getLParenLoc(),
tuple->getElements(),
tuple->getElementNames(),
tuple->getElementNameLocs(),
tuple->getRParenLoc(),
closure);
}
// Deconstruct a parenthesized expression.
auto paren = dyn_cast<ParenExpr>(arg);
return createArgWithTrailingClosure(context,
paren->getLParenLoc(),
paren->getSubExpr(),
{ },
{ },
paren->getRParenLoc(), closure);
}
/// parseExpr
///
/// expr:
/// expr-sequence(basic | trailing-closure)
///
/// \param isExprBasic Whether we're only parsing an expr-basic.
ParserResult<Expr> Parser::parseExprImpl(Diag<> Message, bool isExprBasic) {
// If we see a pattern in expr position, parse it to an UnresolvedPatternExpr.
// Name binding will resolve whether it's in a valid pattern position.
if (isOnlyStartOfMatchingPattern()) {
ParserResult<Pattern> pattern = parseMatchingPattern();
if (pattern.hasCodeCompletion())
return makeParserCodeCompletionResult<Expr>();
if (pattern.isNull())
return nullptr;
return makeParserResult(new (Context) UnresolvedPatternExpr(pattern.get()));
}
ParserResult<Expr> expr = parseExprSequence(Message, isExprBasic);
if (expr.hasCodeCompletion())
return makeParserCodeCompletionResult<Expr>();
if (expr.isNull())
return nullptr;
return makeParserResult(expr.get());
}
/// parseExprIs
/// expr-is:
/// 'is' type
ParserResult<Expr> Parser::parseExprIs() {
SourceLoc isLoc = consumeToken(tok::kw_is);
ParserResult<TypeRepr> type = parseType(diag::expected_type_after_is);
if (type.hasCodeCompletion())
return makeParserCodeCompletionResult<Expr>();
if (type.isNull())
return nullptr;
return makeParserResult(new (Context) IsaExpr(isLoc, type.get()));
}
/// parseExprAs
/// expr-as:
/// 'as' type
/// 'as' '?' type
ParserResult<Expr> Parser::parseExprAs() {
// Parse the 'as'.
SourceLoc asLoc = consumeToken(tok::kw_as);
// Parse the postfix '?'.
SourceLoc questionLoc;
if (Tok.is(tok::question_postfix)) {
questionLoc = consumeToken(tok::question_postfix);
}
ParserResult<TypeRepr> type = parseType(diag::expected_type_after_as);
if (type.hasCodeCompletion())
return makeParserCodeCompletionResult<Expr>();
if (type.isNull())
return nullptr;
Expr *parsed;
if (questionLoc.isValid()) {
parsed = new (Context) ConditionalCheckedCastExpr(asLoc, questionLoc,
type.get());
} else {
parsed = new (Context) UnresolvedCheckedCastExpr(asLoc, type.get());
}
return makeParserResult(parsed);
}
/// parseExprSequence
///
/// expr-sequence(Mode):
/// expr-unary(Mode) expr-binary(Mode)*
/// expr-binary(Mode):
/// operator-binary expr-unary(Mode)
/// '?' expr-sequence(Mode) ':' expr-unary(Mode)
/// '=' expr-unary
/// expr-is
/// expr-as
///
/// The sequencing for binary exprs is not structural, i.e., binary operators
/// are not inherently right-associative. If present, '?' and ':' tokens must
/// match.
ParserResult<Expr> Parser::parseExprSequence(Diag<> Message,
bool isExprBasic,
bool isConfigCondition) {
SmallVector<Expr*, 8> SequencedExprs;
SourceLoc startLoc = Tok.getLoc();
while (true) {
if (isConfigCondition && Tok.isAtStartOfLine())
break;
// Parse a unary expression.
ParserResult<Expr> Primary = parseExprUnary(Message, isExprBasic);
if (Primary.hasCodeCompletion())
return makeParserCodeCompletionResult<Expr>();
if (Primary.isNull())
return nullptr;
// If we got a bare identifier inside a 'var' pattern, it forms a variable
// binding pattern. Raise an error if the identifier shadows an existing
// binding.
//
// TODO: We could check for a bare identifier followed by a non-postfix
// token first thing with a lookahead.
if (InVarOrLetPattern) {
if (auto *declRef = dyn_cast<DeclRefExpr>(Primary.get())) {
// This is ill-formed, but the problem will be caught later by scope
// resolution.
auto pattern = createBindingFromPattern(declRef->getLoc(),
declRef->getDecl()->getName(),
InVarOrLetPattern == IVOLP_InLet);
Primary
= makeParserResult(new (Context) UnresolvedPatternExpr(pattern));
}
if (auto *udre = dyn_cast<UnresolvedDeclRefExpr>(Primary.get())) {
auto pattern = createBindingFromPattern(udre->getLoc(),
udre->getName(),
InVarOrLetPattern == IVOLP_InLet);
Primary
= makeParserResult(new (Context) UnresolvedPatternExpr(pattern));
}
}
SequencedExprs.push_back(Primary.get());
parse_operator:
switch (Tok.getKind()) {
case tok::oper_binary: {
// If '>' is not an operator and this token starts with a '>', we're done.
if (!GreaterThanIsOperator && startsWithGreater(Tok))
goto done;
// Parse the operator.
Expr *Operator = parseExprOperator();
SequencedExprs.push_back(Operator);
// The message is only valid for the first subexpr.
Message = diag::expected_expr_after_operator;
break;
}
case tok::question_infix: {
// Save the '?'.
SourceLoc questionLoc = consumeToken();
// Parse the middle expression of the ternary.
ParserResult<Expr> middle =
parseExprSequence(diag::expected_expr_after_if_question, isExprBasic);
if (middle.hasCodeCompletion())
return makeParserCodeCompletionResult<Expr>();
if (middle.isNull())
return nullptr;
// Make sure there's a matching ':' after the middle expr.
if (!Tok.is(tok::colon)) {
diagnose(questionLoc, diag::expected_colon_after_if_question);
return makeParserErrorResult(new (Context) ErrorExpr(
{startLoc, middle.get()->getSourceRange().End}));
}
SourceLoc colonLoc = consumeToken();
auto *unresolvedIf
= new (Context) IfExpr(questionLoc,
middle.get(),
colonLoc);
SequencedExprs.push_back(unresolvedIf);
Message = diag::expected_expr_after_if_colon;
break;
}
case tok::equal: {
SourceLoc equalsLoc = consumeToken();
auto *assign = new (Context) AssignExpr(equalsLoc);
SequencedExprs.push_back(assign);
Message = diag::expected_expr_assignment;
break;
}
case tok::kw_is: {
// Parse a type after the 'is' token instead of an expression.
ParserResult<Expr> is = parseExprIs();
if (is.isNull() || is.hasCodeCompletion())
return nullptr;
// Store the expr itself as a placeholder RHS. The real RHS is the
// type parameter stored in the node itself.
SequencedExprs.push_back(is.get());
SequencedExprs.push_back(is.get());
// We already parsed the right operand as part of the 'is' production.
// Jump directly to parsing another operator.
goto parse_operator;
}
case tok::kw_as: {
ParserResult<Expr> as = parseExprAs();
if (as.isNull() || as.hasCodeCompletion())
return nullptr;
// Store the expr itself as a placeholder RHS. The real RHS is the
// type parameter stored in the node itself.
SequencedExprs.push_back(as.get());
SequencedExprs.push_back(as.get());
// We already parsed the right operand as part of the 'is' production.
// Jump directly to parsing another operator.
goto parse_operator;
}
default:
// If the next token is not a binary operator, we're done.
goto done;
}
}
done:
if (SequencedExprs.empty()) {
if (isConfigCondition) {
diagnose(startLoc, diag::expected_close_to_config_stmt);
return makeParserError();
} else {
// If we had semantic errors, just fail here.
assert(!SequencedExprs.empty());
}
}
// If we saw no operators, don't build a sequence.
if (SequencedExprs.size() == 1)
return makeParserResult(SequencedExprs[0]);
return makeParserResult(SequenceExpr::create(Context, SequencedExprs));
}
/// parseExprUnary
///
/// expr-unary(Mode):
/// expr-postfix(Mode)
/// expr-new
/// operator-prefix expr-unary(Mode)
/// '&' expr-unary(Mode)
/// expr-discard
///
/// expr-discard: '_'
///
ParserResult<Expr> Parser::parseExprUnary(Diag<> Message, bool isExprBasic) {
UnresolvedDeclRefExpr *Operator;
switch (Tok.getKind()) {
default:
// If the next token is not an operator, just parse this as expr-postfix.
return parseExprPostfix(Message, isExprBasic);
// If the next token is '_', parse a discard expression.
case tok::kw__: {
SourceLoc Loc = consumeToken();
return makeParserResult(
new (Context) DiscardAssignmentExpr(Loc, /*Implicit=*/false));
}
// If the next token is the keyword 'new', this must be expr-new.
case tok::kw_new:
return parseExprNew();
case tok::amp_prefix: {
SourceLoc Loc = consumeToken(tok::amp_prefix);
ParserResult<Expr> SubExpr = parseExprUnary(Message, isExprBasic);
if (SubExpr.hasCodeCompletion())
return makeParserCodeCompletionResult<Expr>();
if (SubExpr.isNull())
return nullptr;
return makeParserResult(
new (Context) InOutExpr(Loc, SubExpr.get(), Type()));
}
case tok::oper_postfix:
// Postfix operators cannot start a subexpression, but can happen
// syntactically because the operator may just follow whatever preceeds this
// expression (and that may not always be an expression).
diagnose(Tok, diag::invalid_postfix_operator);
Tok.setKind(tok::oper_prefix);
SWIFT_FALLTHROUGH;
case tok::oper_prefix:
Operator = parseExprOperator();
break;
case tok::oper_binary: {
// For recovery purposes, accept an oper_binary here.
SourceLoc OperEndLoc = Tok.getLoc().getAdvancedLoc(Tok.getLength());
Tok.setKind(tok::oper_prefix);
Operator = parseExprOperator();
if (OperEndLoc == Tok.getLoc())
diagnose(PreviousLoc, diag::expected_expr_after_unary_operator);
else
diagnose(PreviousLoc, diag::expected_prefix_operator)
.fixItRemoveChars(OperEndLoc, Tok.getLoc());
break;
}
}
ParserResult<Expr> SubExpr = parseExprUnary(Message, isExprBasic);
if (SubExpr.hasCodeCompletion())
return makeParserCodeCompletionResult<Expr>();
if (SubExpr.isNull())
return nullptr;
// Check if we have an unary '-' with integer literal sub-expression, for
// example, "-42".
if (auto *ILE = dyn_cast<IntegerLiteralExpr>(SubExpr.get())) {
if (Operator->hasName() && Operator->getName().str() == "-") {
ILE->setNegative(Operator->getLoc());
return makeParserResult(ILE);
}
}
return makeParserResult(
new (Context) PrefixUnaryExpr(Operator, SubExpr.get()));
}
static DeclRefKind getDeclRefKindForOperator(tok kind) {
switch (kind) {
case tok::oper_binary: return DeclRefKind::BinaryOperator;
case tok::oper_postfix: return DeclRefKind::PostfixOperator;
case tok::oper_prefix: return DeclRefKind::PrefixOperator;
default: llvm_unreachable("bad operator token kind");
}
}
/// parseExprOperator - Parse an operator reference expression. These
/// are not "proper" expressions; they can only appear in binary/unary
/// operators.
UnresolvedDeclRefExpr *Parser::parseExprOperator() {
assert(Tok.isAnyOperator());
DeclRefKind refKind = getDeclRefKindForOperator(Tok.getKind());
SourceLoc loc = Tok.getLoc();
Identifier name = Context.getIdentifier(Tok.getText());
consumeToken();
// Bypass local lookup.
return new (Context) UnresolvedDeclRefExpr(name, refKind, loc);
}
/// parseExprNew
///
/// expr-new:
/// 'new' type-simple expr-new-bounds expr-closure?
/// expr-new-bounds:
/// expr-new-bound
/// expr-new-bounds expr-new-bound
/// expr-new-bound:
/// lsquare-unspaced expr ']'
ParserResult<Expr> Parser::parseExprNew() {
SourceLoc newLoc = Tok.getLoc();
consumeToken(tok::kw_new);
ParserResult<TypeRepr> elementTy = parseTypeSimple();
if (elementTy.hasCodeCompletion())
return makeParserCodeCompletionResult<Expr>();
if (elementTy.isNull())
return makeParserError();
bool hadInvalid = false;
while (Tok.isFollowingLSquare()) {
Parser::StructureMarkerRAII ParsingIndices(*this, Tok);
SourceRange brackets;
brackets.Start = consumeToken(tok::l_square);
// If the bound is missing, that's okay unless this is the first bound.
if (Tok.is(tok::r_square)) {
brackets.End = consumeToken(tok::r_square);
continue;
}
auto boundValue = parseExpr(diag::expected_expr_new_array_bound);
if (boundValue.hasCodeCompletion())
return boundValue;
if (boundValue.isNull() || !Tok.is(tok::r_square)) {
if (!boundValue.isNull())
diagnose(Tok, diag::expected_bracket_array_new);
skipUntil(tok::r_square);
if (!Tok.is(tok::r_square))
return nullptr;
hadInvalid = true;
}
brackets.End = consumeToken(tok::r_square);
}
if (hadInvalid)
return nullptr;
// Check for an initialization closure.
Expr *constructExpr = nullptr;
if (Tok.is(tok::l_brace)) {
ParserResult<Expr> construction = parseExprClosure();
if (construction.hasCodeCompletion())
return construction;
if (construction.isParseError())
return construction;
constructExpr = construction.get();
assert(constructExpr);
}
diagnose(newLoc, diag::array_new_removed);
return makeParserError();
}
static VarDecl *getImplicitSelfDeclForSuperContext(Parser &P,
DeclContext *DC,
SourceLoc Loc) {
if (auto *AFD = dyn_cast<AbstractFunctionDecl>(DC)) {
if (auto *SelfDecl = AFD->getImplicitSelfDecl())
return SelfDecl;
}
P.diagnose(Loc, diag::super_not_in_class_method);
return nullptr;
}
/// parseExprSuper
///
/// expr-super:
/// expr-super-member
/// expr-super-init
/// expr-super-subscript
/// expr-super-member:
/// 'super' '.' identifier
/// expr-super-init:
/// 'super' '.' 'init' expr-paren?
/// 'super' '.' 'init' identifier expr-call-suffix
/// expr-super-subscript:
/// 'super' '[' expr ']'
ParserResult<Expr> Parser::parseExprSuper() {
// Parse the 'super' reference.
SourceLoc superLoc = consumeToken(tok::kw_super);
VarDecl *selfDecl = getImplicitSelfDeclForSuperContext(*this,
CurDeclContext,
superLoc);
bool ErrorOccurred = selfDecl == nullptr;
Expr *superRef = !ErrorOccurred
? cast<Expr>(new (Context) SuperRefExpr(selfDecl, superLoc,
/*Implicit=*/false))
: cast<Expr>(new (Context) ErrorExpr(superLoc));
if (Tok.is(tok::period)) {
// 'super.' must be followed by a member or initializer ref.
SourceLoc dotLoc = consumeToken(tok::period);
// FIXME: This code is copy-paste from the general handling for kw_init.
if (Tok.is(tok::kw_init)) {
if (ErrorOccurred)
return makeParserError();
// super.init
SourceLoc ctorLoc = consumeToken();
// Check that we're actually in an initializer
if (auto *AFD = dyn_cast<AbstractFunctionDecl>(CurDeclContext)) {
if (!isa<ConstructorDecl>(AFD)) {
diagnose(ctorLoc, diag::super_initializer_not_in_initializer);
// No need to indicate error to the caller because this is not a parse
// error.
return makeParserResult(new (Context) ErrorExpr(
SourceRange(superLoc, ctorLoc), ErrorType::get(Context)));
}
}
// The constructor decl will be resolved by sema.
Expr *result = new (Context) UnresolvedConstructorExpr(superRef,
dotLoc, ctorLoc,
/*Implicit=*/false);
if (Tok.isFollowingLParen()) {
// Parse initializer arguments.
ParserResult<Expr> arg = parseExprList(tok::l_paren, tok::r_paren);
if (arg.hasCodeCompletion())
return makeParserCodeCompletionResult<Expr>();
if (arg.isParseError())
return makeParserError();
result = new (Context) CallExpr(result, arg.get(), /*Implicit=*/false);
} else {
// It's invalid to refer to an uncalled initializer.
diagnose(ctorLoc, diag::super_initializer_must_be_called);
result->setType(ErrorType::get(Context));
return makeParserErrorResult(result);
}
// The result of the called initializer is used to rebind 'self'.
return makeParserResult(
new (Context) RebindSelfInConstructorExpr(result, selfDecl));
} else if (Tok.is(tok::code_complete)) {
if (CodeCompletion) {
if (auto *SRE = dyn_cast<SuperRefExpr>(superRef))
CodeCompletion->completeExprSuperDot(SRE);
}
// Eat the code completion token because we handled it.
consumeToken(tok::code_complete);
return makeParserCodeCompletionResult(superRef);
} else {
// super.foo
SourceLoc nameLoc;
Identifier name;
if (parseIdentifier(name, nameLoc,
diag::expected_identifier_after_super_dot_expr))
return nullptr;
return makeParserResult(new (Context) UnresolvedDotExpr(superRef, dotLoc,
name, nameLoc,
/*Implicit=*/false));
}
} else if (Tok.isFollowingLSquare()) {
// super[expr]
ParserResult<Expr> idx = parseExprList(tok::l_square, tok::r_square);
if (idx.hasCodeCompletion())
return makeParserCodeCompletionResult<Expr>();
if (idx.isNull())
return nullptr;
return makeParserResult(new (Context) SubscriptExpr(superRef, idx.get()));
}
if (Tok.is(tok::code_complete)) {
if (CodeCompletion) {
if (auto *SRE = dyn_cast<SuperRefExpr>(superRef))
CodeCompletion->completeExprSuper(SRE);
}
// Eat the code completion token because we handled it.
consumeToken(tok::code_complete);
return makeParserCodeCompletionResult(superRef);
}
diagnose(Tok, diag::expected_dot_or_subscript_after_super);
return nullptr;
}
/// Copy a numeric literal value into AST-owned memory, stripping underscores
/// so the semantic part of the value can be parsed by APInt/APFloat parsers.
static StringRef copyAndStripUnderscores(ASTContext &C, StringRef orig) {
char *start = static_cast<char*>(C.Allocate(orig.size(), 1));
char *p = start;
for (char c : orig)
if (c != '_')
*p++ = c;
return StringRef(start, p - start);
}
/// Disambiguate the parse after '{' token that is in a place that might be
/// the start of a trailing closure, or start the variable accessor block.
///
/// Check to see if the '{' is followed by a 'didSet' or a 'willSet' label,
/// possibly preceeded by attributes. If so, we disambiguate the parse as the
/// start of a get-set block in a variable definition (not as a trailing
/// closure).
static bool isStartOfGetSetAccessor(Parser &P) {
assert(P.Tok.is(tok::l_brace) && "not checking a brace?");
// The only case this can happen is if the accessor label is immediately after
// a brace (possibly preceeded by attributes). "get" is implicit, so it can't
// be checked for. Conveniently however, get/set properties are not allowed
// to have initializers, so we don't have an ambiguity, we just have to check
// for observing accessors.
//
// If we have a 'didSet' or a 'willSet' label, disambiguate immediately as
// an accessor block.
Token NextToken = P.peekToken();
if (NextToken.isContextualKeyword("didSet") ||
NextToken.isContextualKeyword("willSet"))
return true;
// If we don't have attributes, then it can not be an accessor block.
if (NextToken.isNot(tok::at_sign))
return false;
Parser::BacktrackingScope Backtrack(P);
// Eat the "{".
P.consumeToken(tok::l_brace);
// Eat attributes, if present.
if (!P.canParseAttributes())
return false;
// Check if we have 'didSet'/'willSet' after attributes.
return P.Tok.isContextualKeyword("didSet") ||
P.Tok.isContextualKeyword("willSet");
}
/// Map magic literal tokens such as __FILE__ to their
/// MagicIdentifierLiteralExpr kind.
MagicIdentifierLiteralExpr::Kind getMagicIdentifierLiteralKind(tok Kind) {
switch (Kind) {
case tok::kw___COLUMN__:
return MagicIdentifierLiteralExpr::Kind::Column;
case tok::kw___FILE__:
return MagicIdentifierLiteralExpr::Kind::File;
case tok::kw___FUNCTION__:
return MagicIdentifierLiteralExpr::Kind::Function;
case tok::kw___LINE__:
return MagicIdentifierLiteralExpr::Kind::Line;
default:
llvm_unreachable("not a magic literal");
}
}
/// parseExprPostfix
///
/// expr-literal:
/// integer_literal
/// floating_literal
/// string_literal
/// character_literal
/// nil
/// true
/// false
/// '__FILE__'
/// '__LINE__'
/// '__COLUMN__'
/// '__FUNCTION__'
///
/// expr-primary:
/// expr-literal
/// expr-identifier expr-call-suffix?
/// expr-closure
/// expr-anon-closure-argument
/// expr-delayed-identifier
/// expr-paren
/// expr-super
///
/// expr-delayed-identifier:
/// '.' identifier
///
/// expr-dot:
/// expr-postfix '.' 'type'
/// expr-postfix '.' identifier generic-args? expr-call-suffix?
/// expr-postfix '.' integer_literal
///
/// expr-subscript:
/// expr-postfix '[' expr ']'
///
/// expr-call:
/// expr-postfix expr-paren
///
/// expr-force-value:
/// expr-postfix '!'
///
/// expr-trailing-closure:
/// expr-postfix(trailing-closure) expr-closure
///
/// expr-postfix(Mode):
/// expr-postfix(Mode) operator-postfix
///
/// expr-postfix(basic):
/// expr-primary
/// expr-dot
/// expr-metatype
/// expr-init
/// expr-subscript
/// expr-call
/// expr-force-value
///
/// expr-postfix(trailing-closure):
/// expr-postfix(basic)
/// expr-trailing-closure
///
ParserResult<Expr> Parser::parseExprPostfix(Diag<> ID, bool isExprBasic) {
ParserResult<Expr> Result;
switch (Tok.getKind()) {
case tok::integer_literal: {
StringRef Text = copyAndStripUnderscores(Context, Tok.getText());
SourceLoc Loc = consumeToken(tok::integer_literal);
Result = makeParserResult(new (Context) IntegerLiteralExpr(Text, Loc,
/*Implicit=*/false));
break;
}
case tok::floating_literal: {
StringRef Text = copyAndStripUnderscores(Context, Tok.getText());
SourceLoc Loc = consumeToken(tok::floating_literal);
Result = makeParserResult(new (Context) FloatLiteralExpr(Text, Loc,
/*Implicit=*/false));
break;
}
case tok::character_literal: {
uint32_t Codepoint = L->getEncodedCharacterLiteral(Tok);
SourceLoc Loc = consumeToken(tok::character_literal);
Result = makeParserResult(
new (Context) CharacterLiteralExpr(Codepoint, Loc));
break;
}
case tok::string_literal: // "foo"
Result = makeParserResult(parseExprStringLiteral());
break;
case tok::kw_nil:
Result = makeParserResult(
new (Context) NilLiteralExpr(consumeToken(tok::kw_nil)));
break;
case tok::kw_true:
case tok::kw_false: {
bool isTrue = Tok.is(tok::kw_true);
Result = makeParserResult(
new (Context) BooleanLiteralExpr(isTrue, consumeToken()));
break;
}
case tok::kw___FILE__:
case tok::kw___LINE__:
case tok::kw___COLUMN__:
case tok::kw___FUNCTION__: {
auto Kind = getMagicIdentifierLiteralKind(Tok.getKind());
SourceLoc Loc = consumeToken();
Result = makeParserResult(
new (Context) MagicIdentifierLiteralExpr(Kind, Loc, /*Implicit=*/false));
break;
}
case tok::kw_self: // self
case tok::kw_Self: // Self
case tok::identifier: // foo
Result = makeParserResult(parseExprIdentifier());
// If there is an expr-call-suffix, parse it and form a call.
if (Tok.isFollowingLParen()) {
Result = parseExprCallSuffix(Result);
break;
}
break;
case tok::dollarident: // $1
Result = makeParserResult(parseExprAnonClosureArg());
break;
case tok::l_brace: // expr-closure
Result = parseExprClosure();
break;
case tok::period_prefix: { // .foo
SourceLoc DotLoc = consumeToken(tok::period_prefix);
Identifier Name;
SourceLoc NameLoc;
if (parseIdentifier(Name, NameLoc,diag::expected_identifier_after_dot_expr))
return nullptr;
ParserResult<Expr> Arg;
// Check for a () suffix, which indicates a call when constructing
// this member. Note that this cannot be the start of a new line.
if (Tok.isFollowingLParen()) {
Arg = parseExprList(tok::l_paren, tok::r_paren);
if (Arg.hasCodeCompletion())
return makeParserCodeCompletionResult<Expr>();
if (Arg.isNull())
return nullptr;
}
// Handle .foo by just making an AST node.
Result = makeParserResult(
new (Context) UnresolvedMemberExpr(DotLoc, NameLoc, Name,
Arg.getPtrOrNull()));
break;
}
case tok::kw_super: { // super.foo or super[foo]
Result = parseExprSuper();
break;
}
case tok::l_paren:
if (Expr *E = parseExprList(tok::l_paren, tok::r_paren).getPtrOrNull())
Result = makeParserResult(E);
else
Result = makeParserErrorResult<Expr>();
break;
case tok::l_square:
Result = parseExprCollection();
break;
case tok::code_complete:
if (CodeCompletion)
CodeCompletion->completePostfixExprBeginning();
consumeToken(tok::code_complete);
return makeParserCodeCompletionResult<Expr>();
// Eat an invalid token in an expression context. Error tokens are diagnosed
// by the lexer, so there is no reason to emit another diagnostic.
case tok::unknown:
consumeToken(tok::unknown);
return nullptr;
default:
checkForInputIncomplete();
// FIXME: offer a fixit: 'Self' -> 'self'
diagnose(Tok, ID);
return nullptr;
}
// If we had a parse error, don't attempt to parse suffixes.
if (Result.isParseError())
return Result;
bool hasBindOptional = false;
// Handle suffix expressions.
while (1) {
// FIXME: Better recovery.
if (Result.isNull())
return Result;
// Check for a .foo suffix.
SourceLoc TokLoc = Tok.getLoc();
bool IsPeriod = false;
// Look ahead to see if we have '.foo(', '.foo[', '.foo{',
// '.foo.1(', '.foo.1[', or '.foo.1{'.
if (Tok.is(tok::period_prefix) && (peekToken().is(tok::identifier) ||
peekToken().is(tok::integer_literal))) {
BacktrackingScope BS(*this);
consumeToken(tok::period_prefix);
IsPeriod = peekToken().isFollowingLParen() ||
peekToken().isFollowingLSquare() ||
peekToken().is(tok::l_brace);
}
if (consumeIf(tok::period) || (IsPeriod && consumeIf(tok::period_prefix))) {
// Non-identifier cases.
if (Tok.isNot(tok::identifier) && Tok.isNot(tok::integer_literal)) {
// A metatype expr.
if (Tok.is(tok::kw_dynamicType)) {
Result = makeParserResult(
new (Context) DynamicTypeExpr(Result.get(), consumeToken(),
Type()));
continue;
}
// A '.self' expr.
if (Tok.is(tok::kw_self)) {
Result = makeParserResult(
new (Context) DotSelfExpr(Result.get(), TokLoc, consumeToken()));
continue;
}
// If we have '.<keyword><code_complete>', try to recover by creating
// an identifier with the same spelling as the keyword.
if (Tok.isKeyword() && peekToken().is(tok::code_complete)) {
Identifier Name = Context.getIdentifier(Tok.getText());
Result = makeParserResult(
new (Context) UnresolvedDotExpr(Result.get(), TokLoc,
Name, Tok.getLoc(),
/*Implicit=*/false));
consumeToken();
}
// expr-init ::= expr-postfix '.' 'init'.
if (Tok.is(tok::kw_init)) {
// Form the reference to the constructor.
Expr *initRef = new (Context) UnresolvedConstructorExpr(
Result.get(),
TokLoc,
Tok.getLoc(),
/*Implicit=*/false);
SourceLoc initLoc = consumeToken(tok::kw_init);
// FIXME: This is really a semantic restriction for 'self.init'
// masquerading as a parser restriction.
if (Tok.isFollowingLParen()) {
// Parse initializer arguments.
ParserResult<Expr> arg = parseExprList(tok::l_paren, tok::r_paren);
if (arg.hasCodeCompletion())
return makeParserCodeCompletionResult<Expr>();
// FIXME: Unfortunate recovery here.
if (arg.isNull())
return nullptr;
initRef = new (Context) CallExpr(initRef, arg.get(),
/*Implicit=*/false);
// Dig out the 'self' declaration we're using so we can rebind it.
// FIXME: Should be in the type checker, not here.
if (auto func = dyn_cast<AbstractFunctionDecl>(CurDeclContext)) {
if (auto selfDecl = func->getImplicitSelfDecl()) {
initRef = new (Context) RebindSelfInConstructorExpr(initRef,
selfDecl);
}
}
} else {
// It's invalid to refer to an uncalled initializer.
diagnose(initLoc, diag::init_ref_must_be_called);
initRef->setType(ErrorType::get(Context));
}
Result = makeParserResult(initRef);
continue;
}
if (Tok.is(tok::code_complete)) {
if (CodeCompletion && Result.isNonNull())
CodeCompletion->completeDotExpr(Result.get(), /*DotLoc=*/TokLoc);
// Eat the code completion token because we handled it.
consumeToken(tok::code_complete);
Result.setHasCodeCompletion();
return Result;
}
checkForInputIncomplete();
diagnose(Tok, diag::expected_member_name);
return nullptr;
}
// Don't allow '.<integer literal>' following a numeric literal
// expression.
if (Tok.is(tok::integer_literal) && Result.isNonNull() &&
(isa<FloatLiteralExpr>(Result.get()) ||
isa<IntegerLiteralExpr>(Result.get()))) {
diagnose(Tok, diag::numeric_literal_numeric_member)
.highlight(Result.get()->getSourceRange());
consumeToken();
continue;
}
if (Result.isParseError())
continue;
Identifier Name = Context.getIdentifier(Tok.getText());
SourceLoc NameLoc = Tok.getLoc();
if (Tok.is(tok::identifier)) {
consumeToken(tok::identifier);
// If this is a selector reference, collect the selector pieces.
bool IsSelector = false;
if (Tok.is(tok::colon) && peekToken().isIdentifierOrNone()) {
BacktrackingScope BS(*this);
consumeToken(); // ':'
consumeToken(); // identifier or '_'
IsSelector = consumeIf(tok::colon);
}
if (IsSelector) {
// Collect the selector pieces.
SmallVector<UnresolvedSelectorExpr::ComponentLoc, 2> Locs;
SmallVector<Identifier, 2> ArgumentNames;
Locs.push_back({NameLoc, consumeToken(tok::colon)});
// If we aren't splitting prepositions, add entry for the
// unwritten first argument name.
if (!Context.LangOpts.SplitPrepositions) {
Locs.push_back({SourceLoc(), SourceLoc()});
ArgumentNames.push_back(Identifier());
}
while (Tok.isIdentifierOrNone() && peekToken().is(tok::colon)) {
Identifier SelName;
if (Tok.is(tok::identifier))
SelName = Context.getIdentifier(Tok.getText());
SourceLoc SelLoc = consumeToken();
SourceLoc ColonLoc = consumeToken(tok::colon);
Locs.push_back({SelLoc, ColonLoc});
ArgumentNames.push_back(SelName);
}
auto FullName = DeclName(Context, Name, ArgumentNames);
Result = makeParserResult(
UnresolvedSelectorExpr::create(Context, Result.get(), TokLoc,
FullName, Locs));
} else {
Result = makeParserResult(
new (Context) UnresolvedDotExpr(Result.get(), TokLoc, Name, NameLoc,
/*Implicit=*/false));
}
if (canParseAsGenericArgumentList()) {
SmallVector<TypeRepr*, 8> args;
SourceLoc LAngleLoc, RAngleLoc;
if (parseGenericArguments(args, LAngleLoc, RAngleLoc)) {
diagnose(LAngleLoc, diag::while_parsing_as_left_angle_bracket);
}
SmallVector<TypeLoc, 8> locArgs;
for (auto ty : args)
locArgs.push_back(ty);
Result = makeParserResult(new (Context) UnresolvedSpecializeExpr(
Result.get(), LAngleLoc, Context.AllocateCopy(locArgs),
RAngleLoc));
}
// If there is an expr-call-suffix, parse it and form a call.
if (Tok.isFollowingLParen()) {
Result = parseExprCallSuffix(Result);
continue;
}
} else {
Result = makeParserResult(
new (Context) UnresolvedDotExpr(Result.get(), TokLoc, Name, NameLoc,
/*Implicit=*/false));
consumeToken(tok::integer_literal);
}
continue;
}
// Check for a () suffix, which indicates a call.
// Note that this cannot be the start of a new line.
if (Tok.isFollowingLParen()) {
if (peekToken().is(tok::code_complete)) {
consumeToken(tok::l_paren);
CodeCompletion->completePostfixExprParen(Result.get());
// Eat the code completion token because we handled it.
consumeToken(tok::code_complete);
return makeParserCodeCompletionResult<Expr>();
}
ParserResult<Expr> Arg = parseExprList(tok::l_paren, tok::r_paren);
if (Arg.hasCodeCompletion())
return makeParserCodeCompletionResult<Expr>();
if (Arg.isParseError())
return nullptr;
Result = makeParserResult(
new (Context) CallExpr(Result.get(), Arg.get(), /*Implicit=*/false));
continue;
}
// Check for a [expr] suffix.
// Note that this cannot be the start of a new line.
if (Tok.isFollowingLSquare()) {
ParserResult<Expr> Idx = parseExprList(tok::l_square, tok::r_square);
if (Idx.hasCodeCompletion())
return makeParserCodeCompletionResult<Expr>();
if (Idx.isNull() || Result.isNull())
return nullptr;
Result = makeParserResult(
new (Context) SubscriptExpr(Result.get(), Idx.get()));
continue;
}
// Check for a trailing closure, if allowed.
if (!isExprBasic && Tok.is(tok::l_brace) &&
!isStartOfGetSetAccessor(*this)) {
SourceLoc braceLoc = Tok.getLoc();
// Parse the closure.
ParserResult<Expr> closure = parseExprClosure();
if (closure.hasCodeCompletion())
return closure;
if (closure.isParseError())
return closure;
// Track the original end location of the expression we're trailing so
// we can warn about excess newlines.
auto origEndLoc = Result.get()->getEndLoc();
auto origLineCol = SourceMgr.getLineAndColumn(origEndLoc);
auto braceLineCol = SourceMgr.getLineAndColumn(braceLoc);
if (((int)braceLineCol.first - (int)origLineCol.first) > 1) {
diagnose(braceLoc, diag::trailing_closure_excess_newlines);
diagnose(Result.get()->getLoc(), diag::trailing_closure_call_here);
}
// Introduce the trailing closure into the call, or form a call, as
// necessary.
if (auto call = dyn_cast<CallExpr>(Result.get())) {
// When a closure follows a call, it becomes the last argument of
// that call.
Expr *arg = addTrailingClosureToArgument(Context, call->getArg(),
closure.get());
call->setArg(arg);
} else {
// Otherwise, the closure implicitly forms a call.
Expr *arg = createArgWithTrailingClosure(Context, SourceLoc(), { },
{ }, { }, SourceLoc(),
closure.get());
Result = makeParserResult(new (Context) CallExpr(Result.get(), arg,
/*Implicit=*/true));
}
// We only allow a single trailing closure on a call. This could be
// generalized in the future, but needs further design.
if (Tok.is(tok::l_brace)) break;
continue;
}
// Check for a ? suffix.
if (consumeIf(tok::question_postfix)) {
Result = makeParserResult(
new (Context) BindOptionalExpr(Result.get(), TokLoc, /*depth*/ 0));
hasBindOptional = true;
continue;
}
// Check for a ! suffix.
if (consumeIf(tok::exclaim_postfix)) {
Result = makeParserResult(new (Context) ForceValueExpr(Result.get(),
TokLoc));
continue;
}
// Check for a postfix-operator suffix.
if (Tok.is(tok::oper_postfix)) {
// If '>' is not an operator and this token starts with a '>', we're done.
if (!GreaterThanIsOperator && startsWithGreater(Tok))
return Result;
Expr *oper = parseExprOperator();
Result = makeParserResult(
new (Context) PostfixUnaryExpr(oper, Result.get()));
continue;
}
if (Tok.is(tok::code_complete)) {
if (Tok.isAtStartOfLine()) {
// Postfix expression is located on a different line than the code
// completion token, and thus they are not related.
return Result;
}
if (CodeCompletion && Result.isNonNull())
CodeCompletion->completePostfixExpr(Result.get());
// Eat the code completion token because we handled it.
consumeToken(tok::code_complete);
return makeParserCodeCompletionResult<Expr>();
}
break;
}
// If we had a ? suffix expression, bind the entire postfix chain
// within an OptionalEvaluationExpr.
if (hasBindOptional) {
Result = makeParserResult(
new (Context) OptionalEvaluationExpr(Result.get()));
}
return Result;
}
static StringLiteralExpr *
createStringLiteralExprFromSegment(ASTContext &Ctx,
const Lexer *L,
Lexer::StringSegment &Segment,
SourceLoc TokenLoc) {
assert(Segment.Kind == Lexer::StringSegment::Literal);
// FIXME: Consider lazily encoding the string when needed.
llvm::SmallString<256> Buf;
StringRef EncodedStr = L->getEncodedStringSegment(Segment, Buf);
if (!Buf.empty()) {
assert(EncodedStr.begin() == Buf.begin() &&
"Returned string is not from buffer?");
EncodedStr = Ctx.AllocateCopy(EncodedStr);
}
return new (Ctx) StringLiteralExpr(EncodedStr, TokenLoc);
}
/// expr-literal:
/// string_literal
Expr *Parser::parseExprStringLiteral() {
SmallVector<Lexer::StringSegment, 1> Segments;
L->getStringLiteralSegments(Tok, Segments);
SourceLoc Loc = consumeToken();
// The simple case: just a single literal segment.
if (Segments.size() == 1 &&
Segments.front().Kind == Lexer::StringSegment::Literal) {
return createStringLiteralExprFromSegment(Context, L, Segments.front(),
Loc);
}
SmallVector<Expr*, 4> Exprs;
for (auto Segment : Segments) {
switch (Segment.Kind) {
case Lexer::StringSegment::Literal: {
Exprs.push_back(
createStringLiteralExprFromSegment(Context, L, Segment, Loc));
break;
}
case Lexer::StringSegment::Expr: {
// We are going to mess with Tok to do reparsing for interpolated literals,
// don't lose our 'next' token.
llvm::SaveAndRestore<Token> SavedTok(Tok);
// Create a temporary lexer that lexes from the body of the string.
Lexer::State BeginState =
L->getStateForBeginningOfTokenLoc(Segment.Loc);
// We need to set the EOF at r_paren, to prevent the Lexer from eagerly
// trying to lex the token beyond it. Parser::parseList() does a special
// check for a tok::EOF that is spelled with a ')'.
// FIXME: This seems like a hack, there must be a better way..
Lexer::State EndState = BeginState.advance(Segment.Length-1);
Lexer LocalLex(*L, BeginState, EndState);
// Temporarily swap out the parser's current lexer with our new one.
llvm::SaveAndRestore<Lexer *> T(L, &LocalLex);
// Prime the new lexer with a '(' as the first token.
// We might be at tok::eof now, so ensure that consumeToken() does not
// assert about lexing past eof.
Tok.setKind(tok::unknown);
consumeToken();
assert(Tok.is(tok::l_paren));
ParserResult<Expr> E = parseExprList(tok::l_paren, tok::r_paren);
if (E.isNonNull()) {
Exprs.push_back(E.get());
assert(Tok.is(tok::eof) && "segment did not end at close paren");
}
break;
}
}
}
if (Exprs.empty())
return new (Context) ErrorExpr(Loc);
return new (Context) InterpolatedStringLiteralExpr(Loc,
Context.AllocateCopy(Exprs));
}
/// expr-identifier:
/// identifier generic-args?
Expr *Parser::parseExprIdentifier() {
assert(Tok.is(tok::identifier) || Tok.is(tok::kw_self) ||
Tok.is(tok::kw_Self));
Identifier name;
SourceLoc loc = consumeIdentifier(&name);
SmallVector<TypeRepr*, 8> args;
SourceLoc LAngleLoc, RAngleLoc;
bool hasGenericArgumentList = false;
/// The generic-args case is ambiguous with an expression involving '<'
/// and '>' operators. The operator expression is favored unless a generic
/// argument list can be successfully parsed, and the closing bracket is
/// followed by one of these tokens:
/// lparen_following rparen lsquare_following rsquare lbrace rbrace
/// period_following comma semicolon
///
if (canParseAsGenericArgumentList()) {
hasGenericArgumentList = true;
if (parseGenericArguments(args, LAngleLoc, RAngleLoc)) {
diagnose(LAngleLoc, diag::while_parsing_as_left_angle_bracket);
}
}
ValueDecl *D = lookupInScope(name);
if (!D) {
// FIXME: We want this to work: "var x = { x() }", but for now it's better
// to disallow it than to crash.
for (auto activeVar : CurVars.second) {
if (activeVar->getName() == name) {
diagnose(loc, diag::var_init_self_referential);
return new (Context) ErrorExpr(loc);
}
}
}
Expr *E;
if (D == 0) {
auto refKind = DeclRefKind::Ordinary;
auto unresolved = new (Context) UnresolvedDeclRefExpr(name, refKind, loc);
unresolved->setSpecialized(hasGenericArgumentList);
E = unresolved;
} else if (auto TD = dyn_cast<TypeDecl>(D)) {
if (!hasGenericArgumentList)
E = TypeExpr::createForDecl(loc, TD);
else
E = TypeExpr::createForSpecializedDecl(loc, TD,
Context.AllocateCopy(args),
SourceRange(LAngleLoc,
RAngleLoc));
} else {
auto declRef = new (Context) DeclRefExpr(D, loc, /*Implicit=*/false);
declRef->setGenericArgs(args);
E = declRef;
}
if (hasGenericArgumentList) {
SmallVector<TypeLoc, 8> locArgs;
for (auto ty : args)
locArgs.push_back(ty);
E = new (Context) UnresolvedSpecializeExpr(E, LAngleLoc,
Context.AllocateCopy(locArgs),
RAngleLoc);
}
return E;
}
bool Parser::
parseClosureSignatureIfPresent(SmallVectorImpl<CaptureListEntry> &captureList,
Pattern *&params, SourceLoc &arrowLoc,
TypeRepr *&explicitResultType, SourceLoc &inLoc){
// Clear out result parameters.
params = nullptr;
arrowLoc = SourceLoc();
explicitResultType = nullptr;
inLoc = SourceLoc();
// If we have a leading token that may be part of the closure signature, do a
// speculative parse to validate it and look for 'in'.
if (Tok.is(tok::l_paren) || Tok.isIdentifierOrNone() ||
Tok.is(tok::l_square)) {
BacktrackingScope backtrack(*this);
// Skip by a closure capture list if present.
if (consumeIf(tok::l_square)) {
skipUntil(tok::r_square);
if (!consumeIf(tok::r_square))
return false;
}
// Parse pattern-tuple func-signature-result? 'in'.
if (consumeIf(tok::l_paren)) { // Consume the ')'.
// While we don't have '->' or ')', eat balanced tokens.
while (!Tok.is(tok::r_paren) && !Tok.is(tok::eof))
skipSingle();
// Consume the ')', if it's there.
if (consumeIf(tok::r_paren)) {
// Parse the func-signature-result, if present.
if (consumeIf(tok::arrow)) {
if (!canParseType())
return false;
}
}
// Okay, we have a closure signature.
} else if (Tok.isIdentifierOrNone()) {
// Parse identifier (',' identifier)*
consumeToken();
while (consumeIf(tok::comma)) {
if (Tok.isIdentifierOrNone()) {
consumeToken();
continue;
}
return false;
}
// Parse the func-signature-result, if present.
if (consumeIf(tok::arrow)) {
if (!canParseType())
return false;
}
}
// Parse the 'in' at the end.
if (Tok.isNot(tok::kw_in))
return false;
// Okay, we have a closure signature.
} else {
// No closure signature.
return false;
}
// At this point, we know we have a closure signature. Parse the capture list
// and parameters.
if (consumeIf(tok::l_square) &&
!consumeIf(tok::r_square)) {
do {
// Check for the strength specifier: "strong", "weak", "unowned", or
// "unowned(safe/unsafe)".
SourceLoc loc;
AttrKind attrKind = AK_Count;
if (Tok.isContextualKeyword("strong")){
loc = consumeToken(tok::identifier);
attrKind = AK_strong;
} else if (Tok.isContextualKeyword("weak")){
loc = consumeToken(tok::identifier);
attrKind = AK_weak;
} else if (Tok.isContextualKeyword("unowned")) {
loc = consumeToken(tok::identifier);
attrKind = AK_unowned;
// Skip over "safe" and "unsafe" if present.
if (consumeIf(tok::l_paren)) {
if (Tok.getText() == "safe")
attrKind = AK_unowned; // FIXME: No "safe" variant.
else if (Tok.getText() == "unsafe")
attrKind = AK_unowned_unsafe;
else
diagnose(Tok, diag::attr_unowned_invalid_specifier);
consumeIf(tok::identifier);
if (!consumeIf(tok::r_paren))
diagnose(Tok, diag::attr_unowned_expected_rparen);
}
} else if (Tok.is(tok::identifier) &&
peekToken().isAny(tok::equal, tok::comma, tok::r_square)) {
// "x = 42", "x," and "x]" are all strong captures of x.
loc = Tok.getLoc();
} else {
diagnose(Tok, diag::expected_capture_specifier);
skipUntil(tok::comma, tok::r_square);
continue;
}
if (Tok.isNot(tok::identifier, tok::kw_self)) {
diagnose(Tok, diag::expected_capture_specifier_name);
skipUntil(tok::comma, tok::r_square);
continue;
}
// The thing being capture specified is an identifier, or as an identifier
// followed by an expression.
Expr *initializer;
Identifier name;
SourceLoc nameLoc = Tok.getLoc();
if (peekToken().isNot(tok::equal)) {
// If this is the simple case, then the identifier is both the name and
// the expression to capture.
name = Context.getIdentifier(Tok.getText());
initializer = parseExprIdentifier();
// It is a common error to try to capture a nested field instead of just
// a local name, reject it with a specific error message.
if (Tok.isAny(tok::period, tok::exclaim_postfix,tok::question_postfix)){
diagnose(Tok, diag::cannot_capture_fields);
skipUntil(tok::comma, tok::r_square);
continue;
}
} else {
// Otherwise, the name is a new declaration.
consumeIdentifier(&name);
consumeToken(tok::equal);
auto ExprResult = parseExpr(diag::expected_init_capture_specifier);
if (ExprResult.isNull())
continue;
initializer = ExprResult.get();
}
// Create the VarDecl and the PatternBindingDecl for the captured
// expression. This uses the parent declcontext (not the closure) since
// the initializer expression is evaluated before the closure is formed.
auto *VD = new (Context) VarDecl(/*isStatic*/false,
/*isLet*/attrKind != AK_weak,
nameLoc, name, Type(), CurDeclContext);
// Attributes.
if (attrKind != AK_Count) {
DeclAttributes Attributes;
Attributes.setAttr(attrKind, loc);
VD->getMutableAttrs() = Attributes;
}
auto pattern = new (Context) NamedPattern(VD, /*implicit*/true);
auto *PBD = new (Context) PatternBindingDecl(/*staticloc*/SourceLoc(),
StaticSpellingKind::None,
nameLoc, pattern,initializer,
/*isconditional*/false,
CurDeclContext);
captureList.push_back(CaptureListEntry(VD, PBD));
} while (consumeIf(tok::comma));
// The capture list needs to be closed off with a ']'.
if (!consumeIf(tok::r_square)) {
diagnose(Tok, diag::expected_capture_list_end_rsquare);
skipUntil(tok::r_square);
if (Tok.is(tok::r_square))
consumeToken(tok::r_square);
}
}
bool invalid = false;
if (Tok.isNot(tok::kw_in)) {
if (Tok.is(tok::l_paren)) {
// Parse the closure arguments.
auto pattern = parseSingleParameterClause(ParameterContextKind::Closure);
if (pattern.isNonNull())
params = pattern.get();
else
invalid = true;
} else {
// Parse identifier (',' identifier)*
SmallVector<TuplePatternElt, 4> elements;
do {
if (Tok.is(tok::identifier) || Tok.is(tok::kw__)) {
Identifier name = Tok.is(tok::identifier) ?
Context.getIdentifier(Tok.getText()) : Identifier();
auto var = new (Context) ParamDecl(/*IsLet*/ true,
SourceLoc(), Identifier(),
Tok.getLoc(),
name,
Type(), nullptr);
elements.push_back(TuplePatternElt(new (Context) NamedPattern(var)));
consumeToken();
} else {
diagnose(Tok, diag::expected_closure_parameter_name);
invalid = true;
break;
}
// Consume a comma to continue.
if (consumeIf(tok::comma)) {
continue;
}
break;
} while (true);
params = TuplePattern::create(Context, SourceLoc(), elements,SourceLoc());
}
// Parse the optional explicit return type.
if (Tok.is(tok::arrow)) {
// Consume the '->'.
arrowLoc = consumeToken();
// Parse the type.
explicitResultType =
parseType(diag::expected_closure_result_type).getPtrOrNull();
if (!explicitResultType) {
// If we couldn't parse the result type, clear out the arrow location.
arrowLoc = SourceLoc();
invalid = true;
}
}
}
// Parse the 'in'.
if (Tok.is(tok::kw_in)) {
inLoc = consumeToken();
} else {
// Scan forward to see if we can find the 'in'. This re-synchronizes the
// parser so we can at least parse the body correctly.
SourceLoc startLoc = Tok.getLoc();
ParserPosition pos = getParserPosition();
while (Tok.isNot(tok::eof) && !Tok.is(tok::kw_in) &&
Tok.isNot(tok::r_brace)) {
skipSingle();
}
if (Tok.is(tok::kw_in)) {
// We found the 'in'. If this is the first error, complain about the
// junk tokens in-between but re-sync at the 'in'.
if (!invalid) {
diagnose(startLoc, diag::unexpected_tokens_before_closure_in);
}
inLoc = consumeToken();
} else {
// We didn't find an 'in', backtrack to where we started. If this is the
// first error, complain about the missing 'in'.
backtrackToPosition(pos);
if (!invalid) {
diagnose(Tok, diag::expected_closure_in)
.fixItInsert(Tok.getLoc(), "in ");
}
inLoc = Tok.getLoc();
}
}
return invalid;
}
ParserResult<Expr> Parser::parseExprClosure() {
assert(Tok.is(tok::l_brace) && "Not at a left brace?");
// Parse the opening left brace.
SourceLoc leftBrace = consumeToken();
// Parse the closure-signature, if present.
Pattern *params = nullptr;
SourceLoc arrowLoc;
TypeRepr *explicitResultType;
SourceLoc inLoc;
SmallVector<CaptureListEntry, 2> captureList;
parseClosureSignatureIfPresent(captureList, params, arrowLoc,
explicitResultType, inLoc);
// If the closure was created in the context of an array type signature's
// size expression, there will not be a local context. A parse error will
// be reported at the signature's declaration site.
if (!CurLocalContext) {
skipUntil(tok::r_brace);
if (Tok.is(tok::r_brace))
consumeToken();
return makeParserError();
}
unsigned discriminator = CurLocalContext->claimNextClosureDiscriminator();
// Create the closure expression and enter its context.
auto *closure = new (Context) ClosureExpr(Context.AllocateCopy(captureList),
params, arrowLoc, inLoc,
explicitResultType,
discriminator, CurDeclContext);
// The arguments to the func are defined in their own scope.
Scope S(this, ScopeKind::ClosureParams);
ParseFunctionBody cc(*this, closure);
// Handle parameters.
if (params) {
// Add the parameters into scope.
addPatternVariablesToScope(params);
} else {
// There are no parameters; allow anonymous closure variables.
// FIXME: We could do this all the time, and then provide Fix-Its
// to map $i -> the appropriately-named argument. This might help
// users who are refactoring code by adding names.
AnonClosureVars.emplace_back();
}
// Add capture list variables to scope.
for (auto c : captureList)
addToScope(c.Var);
// Parse the body.
SmallVector<ASTNode, 4> bodyElements;
ParserStatus status;
status |= parseBraceItems(bodyElements, BraceItemListKind::Brace);
// Parse the closing '}'.
SourceLoc rightBrace;
parseMatchingToken(tok::r_brace, rightBrace, diag::expected_closure_rbrace,
leftBrace);
// If we didn't have any parameters, create a parameter list from the
// anonymous closure arguments.
if (!params) {
// Create a parameter pattern containing the anonymous variables.
auto& anonVars = AnonClosureVars.back();
SmallVector<TuplePatternElt, 4> elements;
for (auto anonVar : anonVars) {
elements.push_back(TuplePatternElt(new (Context) NamedPattern(anonVar)));
}
params = TuplePattern::createSimple(Context, SourceLoc(), elements,
SourceLoc());
// Pop out of the anonymous closure variables scope.
AnonClosureVars.pop_back();
// Attach the parameters to the closure.
closure->setParams(params);
closure->setHasAnonymousClosureVars();
}
// If the body consists of a single expression, turn it into a return
// statement.
bool hasSingleExpressionBody = false;
if (bodyElements.size() == 1 && bodyElements[0].is<Expr *>()) {
hasSingleExpressionBody = true;
bodyElements[0] = new (Context) ReturnStmt(SourceLoc(),
bodyElements[0].get<Expr*>());
}
// Set the body of the closure.
closure->setBody(BraceStmt::create(Context, leftBrace, bodyElements,
rightBrace),
hasSingleExpressionBody);
return makeParserResult(closure);
}
/// expr-anon-closure-argument:
/// dollarident
Expr *Parser::parseExprAnonClosureArg() {
StringRef Name = Tok.getText();
SourceLoc Loc = consumeToken(tok::dollarident);
assert(Name[0] == '$' && "Not a dollarident");
// We know from the lexer that this is all-numeric.
unsigned ArgNo = 0;
if (Name.substr(1).getAsInteger(10, ArgNo)) {
diagnose(Loc.getAdvancedLoc(1), diag::dollar_numeric_too_large);
return new (Context) ErrorExpr(Loc);
}
// If this is a closure expression that did not have any named parameters,
// generate the anonymous variables we need.
auto closure = dyn_cast_or_null<ClosureExpr>(
dyn_cast<AbstractClosureExpr>(CurDeclContext));
if (!closure || closure->getParams()) {
// FIXME: specialize diagnostic when there were closure parameters.
// We can be fairly smart here.
diagnose(Loc, closure ? diag::anon_closure_arg_in_closure_with_args
: diag::anon_closure_arg_not_in_closure);
return new (Context) ErrorExpr(Loc);
}
auto &decls = AnonClosureVars.back();
while (ArgNo >= decls.size()) {
unsigned nextIdx = decls.size();
SmallVector<char, 4> StrBuf;
StringRef varName = ("$" + Twine(nextIdx)).toStringRef(StrBuf);
Identifier ident = Context.getIdentifier(varName);
SourceLoc varLoc = Loc;
VarDecl *var = new (Context) ParamDecl(/*IsLet*/ true,
SourceLoc(), Identifier(),
varLoc, ident, Type(), closure);
decls.push_back(var);
}
return new (Context) DeclRefExpr(AnonClosureVars.back()[ArgNo], Loc,
/*Implicit=*/false);
}
/// parseExprList - Parse a list of expressions.
///
/// expr-paren:
/// lparen-any ')'
/// lparen-any binary-op ')'
/// lparen-any expr-paren-element (',' expr-paren-element)* ')'
///
/// expr-paren-element:
/// (identifier ':')? expr
///
ParserResult<Expr> Parser::parseExprList(tok LeftTok, tok RightTok) {
StructureMarkerRAII ParsingExprList(*this, Tok);
SourceLoc LLoc = consumeToken(LeftTok);
SourceLoc RLoc;
SmallVector<Expr*, 8> SubExprs;
SmallVector<Identifier, 8> SubExprNames;
SmallVector<SourceLoc, 8> SubExprNameLocs;
ParserStatus Status = parseList(RightTok, LLoc, RLoc,
tok::comma, /*OptionalSep=*/false,
/*AllowSepAfterLast=*/false,
RightTok == tok::r_paren ?
diag::expected_rparen_expr_list :
diag::expected_rsquare_expr_list,
[&] () -> ParserStatus {
Identifier FieldName;
SourceLoc FieldNameLoc;
// Check to see if there is a field specifier
if (Tok.is(tok::identifier) && peekToken().is(tok::colon)) {
FieldNameLoc = Tok.getLoc();
if (parseIdentifier(FieldName,
diag::expected_field_spec_name_tuple_expr)) {
return makeParserError();
}
consumeToken(tok::colon);
}
// See if we have an operator decl ref '(<op>)'. The operator token in
// this case lexes as a binary operator because it neither leads nor
// follows a proper subexpression.
ParserStatus Status;
Expr *SubExpr = nullptr;
if (Tok.is(tok::oper_binary) &&
(peekToken().is(RightTok) || peekToken().is(tok::comma))) {
SourceLoc Loc;
Identifier OperName;
if (parseAnyIdentifier(OperName, Loc, diag::expected_operator_ref)) {
return makeParserError();
}
// Bypass local lookup. Use an 'Ordinary' reference kind so that the
// reference may resolve to any unary or binary operator based on
// context.
SubExpr = new(Context) UnresolvedDeclRefExpr(OperName,
DeclRefKind::Ordinary,
Loc);
} else {
ParserResult<Expr> ParsedSubExpr
= parseExpr(diag::expected_expr_in_expr_list);
SubExpr = ParsedSubExpr.getPtrOrNull();
Status = ParsedSubExpr;
}
// If we got a subexpression, add it.
if (SubExpr) {
// Update names and locations.
if (!SubExprNames.empty()) {
SubExprNames.push_back(FieldName);
SubExprNameLocs.push_back(FieldNameLoc);
} else if (FieldName.get()) {
SubExprNames.resize(SubExprs.size());
SubExprNames.push_back(FieldName);
SubExprNameLocs.resize(SubExprs.size());
SubExprNameLocs.push_back(FieldNameLoc);
}
// Add the subexpression.
SubExprs.push_back(SubExpr);
}
return Status;
});
if (Status.hasCodeCompletion())
return makeParserCodeCompletionResult<Expr>();
// A tuple with a single, unlabelled element is just parentheses.
if (SubExprs.size() == 1 &&
(SubExprNames.empty() || SubExprNames[0].empty())) {
return makeParserResult(
Status, new (Context) ParenExpr(LLoc, SubExprs[0], RLoc,
/*hasTrailingClosure=*/false));
}
return makeParserResult(
TupleExpr::create(Context, LLoc, SubExprs, SubExprNames, SubExprNameLocs,
RLoc, /*hasTrailingClosure=*/false, /*Implicit=*/false));
}
/// \brief Parse an expression call suffix.
///
/// expr-call-suffix:
/// expr-paren selector-arg*
/// expr-closure selector-arg* (except in expr-basic)
///
/// selector-arg:
/// identifier expr-paren
ParserResult<Expr>
Parser::parseExprCallSuffix(ParserResult<Expr> fn,
Identifier firstSelectorPiece,
SourceLoc firstSelectorPieceLoc) {
assert(Tok.isFollowingLParen() && "Not a call suffix?");
// Parse the first argument.
// If there is a code completion token right after the '(', do a special case
// callback.
if (peekToken().is(tok::code_complete) && CodeCompletion) {
consumeToken(tok::l_paren);
CodeCompletion->completePostfixExprParen(fn.get());
// Eat the code completion token because we handled it.
consumeToken(tok::code_complete);
return makeParserCodeCompletionResult<Expr>();
}
ParserResult<Expr> firstArg = parseExprList(Tok.getKind(), tok::r_paren);
if (firstArg.hasCodeCompletion())
return firstArg;
if (fn.isParseError())
return fn;
if (firstArg.isParseError())
return firstArg;
// Form the call.
return makeParserResult(new (Context) CallExpr(fn.get(), firstArg.get(),
/*Implicit=*/false));
}
/// parseExprCollection - Parse a collection literal expression.
///
/// expr-collection:
/// expr-array
/// expr-dictionary
// lsquare-starting ']'
ParserResult<Expr> Parser::parseExprCollection() {
Parser::StructureMarkerRAII ParsingCollection(*this, Tok);
SourceLoc LSquareLoc = consumeToken(tok::l_square);
// [] is always an array.
if (Tok.is(tok::r_square)) {
SourceLoc RSquareLoc = consumeToken();
auto EmptyTuple = TupleExpr::createEmpty(Context, LSquareLoc,
RSquareLoc, /*Implicit=*/false);
return makeParserResult(
new (Context) ArrayExpr(LSquareLoc, EmptyTuple, RSquareLoc));
}
// [:] is always an empty dictionary.
if (Tok.is(tok::colon) && peekToken().is(tok::r_square)) {
consumeToken(tok::colon);
SourceLoc RSquareLoc = consumeToken();
auto EmptyTuple = TupleExpr::createEmpty(Context, LSquareLoc,
RSquareLoc, /*Implicit=*/false);
return makeParserResult(
new (Context) DictionaryExpr(LSquareLoc, EmptyTuple, RSquareLoc));
}
// Parse the first expression.
ParserResult<Expr> FirstExpr
= parseExpr(diag::expected_expr_in_collection_literal);
if (FirstExpr.isNull() || FirstExpr.hasCodeCompletion()) {
skipUntil(tok::r_square);
if (Tok.is(tok::r_square))
consumeToken();
if (FirstExpr.hasCodeCompletion())
return makeParserCodeCompletionResult<Expr>();
return nullptr;
}
// If we have a ':', this is a dictionary literal.
if (Tok.is(tok::colon)) {
return parseExprDictionary(LSquareLoc, FirstExpr.get());
}
// Otherwise, we have an array literal.
return parseExprArray(LSquareLoc, FirstExpr.get());
}
/// parseExprArray - Parse an array literal expression.
///
/// The lsquare-starting and first expression have already been
/// parsed, and are passed in as parameters.
///
/// expr-array:
/// '[' expr (',' expr)* ','? ']'
/// '[' ']'
ParserResult<Expr> Parser::parseExprArray(SourceLoc LSquareLoc,
Expr *FirstExpr) {
SmallVector<Expr *, 8> SubExprs;
SubExprs.push_back(FirstExpr);
SourceLoc RSquareLoc;
ParserStatus Status;
if (Tok.isNot(tok::r_square) && !consumeIf(tok::comma)) {
SourceLoc InsertLoc = Lexer::getLocForEndOfToken(SourceMgr, PreviousLoc);
diagnose(Tok, diag::expected_separator, ",")
.fixItInsert(InsertLoc, ",");
Status.setIsParseError();
}
Status |= parseList(tok::r_square, LSquareLoc, RSquareLoc,
tok::comma, /*OptionalSep=*/false,
/*AllowSepAfterLast=*/true,
diag::expected_rsquare_array_expr,
[&] () -> ParserStatus {
ParserResult<Expr> Element
= parseExpr(diag::expected_expr_in_collection_literal);
if (Element.isNonNull())
SubExprs.push_back(Element.get());
return Element;
});
if (Status.hasCodeCompletion())
return makeParserCodeCompletionResult<Expr>();
assert(SubExprs.size() >= 1);
Expr *SubExpr;
if (SubExprs.size() == 1) {
SubExpr = new (Context) ParenExpr(LSquareLoc, SubExprs[0],
RSquareLoc,
/*hasTrailingClosure=*/false);
} else {
SubExpr = TupleExpr::create(Context, LSquareLoc, SubExprs, { }, { },
RSquareLoc, /*hasTrailingClosure=*/false,
/*Implicit=*/false);
}
return makeParserResult(
Status, new (Context) ArrayExpr(LSquareLoc, SubExpr, RSquareLoc));
}
/// parseExprDictionary - Parse a dictionary literal expression.
///
/// The lsquare-starting and first key have already been parsed, and
/// are passed in as parameters.
///
/// expr-dictionary:
/// '[' expr ':' expr (',' expr ':' expr)* ','? ']'
/// '[' ':' ']'
ParserResult<Expr> Parser::parseExprDictionary(SourceLoc LSquareLoc,
Expr *FirstKey) {
assert(Tok.is(tok::colon));
// Each subexpression is a (key, value) tuple.
// FIXME: We're not tracking the colon locations in the AST.
SmallVector<Expr *, 8> SubExprs;
SourceLoc RSquareLoc;
// Function that adds a new key/value pair.
auto addKeyValuePair = [&](Expr *Key, Expr *Value) -> void {
Expr *Exprs[] = {Key, Value};
SubExprs.push_back(TupleExpr::createImplicit(Context, Exprs, { }));
};
bool FirstPair = true;
ParserStatus Status =
parseList(tok::r_square, LSquareLoc, RSquareLoc, tok::comma,
/*OptionalSep=*/false, /*AllowSepAfterLast=*/true,
diag::expected_rsquare_array_expr, [&]() -> ParserStatus {
// Parse the next key.
ParserResult<Expr> Key;
if (FirstPair) {
Key = makeParserResult(FirstKey);
FirstPair = false;
} else {
Key = parseExpr(diag::expected_key_in_dictionary_literal);
if (Key.isNull() || Key.hasCodeCompletion())
return Key;
}
// Parse the ':'.
if (Tok.isNot(tok::colon)) {
diagnose(Tok, diag::expected_colon_in_dictionary_literal);
return makeParserError();
}
consumeToken();
// Parse the next value.
ParserResult<Expr> Value =
parseExpr(diag::expected_value_in_dictionary_literal);
if (Value.hasCodeCompletion())
return Value;
if (Value.isNull())
Value = makeParserResult(Value, new (Context) ErrorExpr(PreviousLoc));
// Add this key/value pair.
addKeyValuePair(Key.get(), Value.get());
return Value;
});
if (Status.hasCodeCompletion())
return makeParserCodeCompletionResult<Expr>();
assert(SubExprs.size() >= 1);
Expr *SubExpr;
if (SubExprs.size() == 1)
SubExpr = new (Context) ParenExpr(LSquareLoc, SubExprs[0], RSquareLoc,
/*hasTrailingClosure=*/false);
else
SubExpr = TupleExpr::create(Context, LSquareLoc, SubExprs, { }, { },
RSquareLoc, /*hasTrailingClosure=*/false,
/*Implicit=*/false);
return makeParserResult(new (Context)
DictionaryExpr(LSquareLoc, SubExpr, RSquareLoc));
}
void Parser::addPatternVariablesToScope(ArrayRef<Pattern *> Patterns) {
for (Pattern *Pat : Patterns) {
Pat->forEachVariable([&](VarDecl *VD) {
if (VD->hasName()) {
// Add any variable declarations to the current scope.
addToScope(VD);
}
});
}
}
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