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Merged
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Aug 6, 2022
Merged

Formalize Labeled Syntax #60396

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18 changes: 10 additions & 8 deletions lib/Parse/ParseStmt.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -524,22 +524,24 @@ static ParserResult<Stmt> recoverFromInvalidCase(Parser &P) {
ParserResult<Stmt> Parser::parseStmt() {
AssertParserMadeProgressBeforeLeavingScopeRAII apmp(*this);

SyntaxParsingContext LocalContext(SyntaxContext, SyntaxContextKind::Stmt);

// Note that we're parsing a statement.
StructureMarkerRAII ParsingStmt(*this, Tok.getLoc(),
StructureMarkerKind::Statement);

LabeledStmtInfo LabelInfo;

// If this is a label on a loop/switch statement, consume it and pass it into
// parsing logic below.
SyntaxParsingContext LabelContext(SyntaxContext, SyntaxKind::LabeledStmt);
LabeledStmtInfo LabelInfo;
if (Tok.is(tok::identifier) && peekToken().is(tok::colon)) {
LabelInfo.Loc = consumeIdentifier(LabelInfo.Name,
/*diagnoseDollarPrefix=*/true);
consumeToken(tok::colon);
} else {
LabelContext.setTransparent();
}

SyntaxParsingContext LocalContext(SyntaxContext, SyntaxContextKind::Stmt);

// Note that we're parsing a statement.
StructureMarkerRAII ParsingStmt(*this, Tok.getLoc(),
StructureMarkerKind::Statement);

SourceLoc tryLoc;
(void)consumeIf(tok::kw_try, tryLoc);

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14 changes: 7 additions & 7 deletions test/Syntax/Outputs/round_trip_parse_gen.swift.withkinds
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Expand Up @@ -345,19 +345,19 @@ func statementTests<FunctionSignature><ParameterClause>() </ParameterClause></Fu
} </CodeBlock></CatchClause><CatchClause>catch <CatchItem><ExpressionPattern><FunctionCallExpr><MemberAccessExpr>.a</MemberAccessExpr>(<TupleExprElement><UnresolvedPatternExpr><ValueBindingPattern>let <IdentifierPattern>a</IdentifierPattern></ValueBindingPattern></UnresolvedPatternExpr></TupleExprElement>)</FunctionCallExpr></ExpressionPattern>, </CatchItem><CatchItem><ExpressionPattern><FunctionCallExpr><MemberAccessExpr>.b</MemberAccessExpr>(<TupleExprElement><UnresolvedPatternExpr><ValueBindingPattern>let <IdentifierPattern>b</IdentifierPattern></ValueBindingPattern></UnresolvedPatternExpr></TupleExprElement>) </FunctionCallExpr></ExpressionPattern><WhereClause>where <SequenceExpr><IdentifierExpr>b </IdentifierExpr><BinaryOperatorExpr>== </BinaryOperatorExpr><StringLiteralExpr>"<StringSegment></StringSegment>" </StringLiteralExpr></SequenceExpr></WhereClause></CatchItem><CodeBlock>{
} </CodeBlock></CatchClause><CatchClause>catch <CatchItem></CatchItem><CodeBlock>{
}</CodeBlock></CatchClause></DoStmt><RepeatWhileStmt>
repeat <CodeBlock>{ } </CodeBlock>while <BooleanLiteralExpr>true</BooleanLiteralExpr></RepeatWhileStmt><RepeatWhileStmt>
LABEL: repeat <CodeBlock>{ } </CodeBlock>while <BooleanLiteralExpr>false</BooleanLiteralExpr></RepeatWhileStmt><WhileStmt>
while <ConditionElement><BooleanLiteralExpr>true </BooleanLiteralExpr></ConditionElement><CodeBlock>{ }</CodeBlock></WhileStmt><WhileStmt>
LABEL: while <ConditionElement><BooleanLiteralExpr>true </BooleanLiteralExpr></ConditionElement><CodeBlock>{ }</CodeBlock></WhileStmt><DoStmt>
LABEL: do <CodeBlock>{}</CodeBlock></DoStmt><SwitchStmt>
LABEL: switch <IdentifierExpr>foo </IdentifierExpr>{<SwitchCase><SwitchCaseLabel>
repeat <CodeBlock>{ } </CodeBlock>while <BooleanLiteralExpr>true</BooleanLiteralExpr></RepeatWhileStmt><LabeledStmt>
LABEL: <RepeatWhileStmt>repeat <CodeBlock>{ } </CodeBlock>while <BooleanLiteralExpr>false</BooleanLiteralExpr></RepeatWhileStmt></LabeledStmt><WhileStmt>
while <ConditionElement><BooleanLiteralExpr>true </BooleanLiteralExpr></ConditionElement><CodeBlock>{ }</CodeBlock></WhileStmt><LabeledStmt>
LABEL: <WhileStmt>while <ConditionElement><BooleanLiteralExpr>true </BooleanLiteralExpr></ConditionElement><CodeBlock>{ }</CodeBlock></WhileStmt></LabeledStmt><LabeledStmt>
LABEL: <DoStmt>do <CodeBlock>{}</CodeBlock></DoStmt></LabeledStmt><LabeledStmt>
LABEL: <SwitchStmt>switch <IdentifierExpr>foo </IdentifierExpr>{<SwitchCase><SwitchCaseLabel>
case <CaseItem><ExpressionPattern><IntegerLiteralExpr>1</IntegerLiteralExpr></ExpressionPattern></CaseItem>:</SwitchCaseLabel><FallthroughStmt>
fallthrough</FallthroughStmt></SwitchCase><SwitchCase><SwitchCaseLabel>
case <CaseItem><ExpressionPattern><IntegerLiteralExpr>2</IntegerLiteralExpr></ExpressionPattern></CaseItem>:</SwitchCaseLabel><BreakStmt>
break LABEL</BreakStmt></SwitchCase><SwitchCase><SwitchCaseLabel>
case <CaseItem><ExpressionPattern><IntegerLiteralExpr>3</IntegerLiteralExpr></ExpressionPattern></CaseItem>:</SwitchCaseLabel><BreakStmt>
break</BreakStmt></SwitchCase>
}</SwitchStmt><ForInStmt>
}</SwitchStmt></LabeledStmt><ForInStmt>

for <IdentifierPattern>a </IdentifierPattern>in <IdentifierExpr>b </IdentifierExpr><CodeBlock>{<DeferStmt>
defer <CodeBlock>{ <TupleExpr>() </TupleExpr>}</CodeBlock></DeferStmt><IfStmt>
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1 change: 1 addition & 0 deletions utils/gyb_syntax_support/NodeSerializationCodes.py
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Expand Up @@ -268,6 +268,7 @@
'MissingType': 264,
'MissingPattern': 265,
'GarbageNodes' : 266,
'LabeledStmt': 267,
}


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2 changes: 1 addition & 1 deletion utils/gyb_syntax_support/PatternNodes.py
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Expand Up @@ -73,7 +73,7 @@

# tuple-pattern-element -> identifier? ':' pattern ','?
Node('TuplePatternElement', kind='Syntax',
traits=['WithTrailingComma', 'Labeled'],
traits=['WithTrailingComma'],
children=[
Child('LabelName', kind='IdentifierToken',
is_optional=True),
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44 changes: 14 additions & 30 deletions utils/gyb_syntax_support/StmtNodes.py
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Expand Up @@ -2,6 +2,14 @@
from .Node import Node # noqa: I201

STMT_NODES = [
# labeled-stmt -> label ':' stmt
Node('LabeledStmt', kind='Stmt',
children=[
Child('LabelName', kind='IdentifierToken'),
Child('LabelColon', kind='ColonToken'),
Child('Statement', kind='Stmt'),
]),

# continue-stmt -> 'continue' label? ';'?
Node('ContinueStmt', kind='Stmt',
children=[
Expand All @@ -12,12 +20,8 @@

# while-stmt -> label? ':'? 'while' condition-list code-block ';'?
Node('WhileStmt', kind='Stmt',
traits=['WithCodeBlock', 'Labeled'],
traits=['WithCodeBlock'],
Comment on lines 21 to +23
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Should the specifications be updated as well?

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@CodaFi CodaFi Sep 8, 2022 •
edited
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What specification are you referring to? The "grammar" is still correct - we don't necessarily want the notion of a "labeled statement" in the formal grammar since not all the statements support labels!

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@AnthonyLatsis AnthonyLatsis Sep 8, 2022 •
edited
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I was referring to the comment in the above preview (ditto the other nodes you modified), not the actual grammar in the language reference, although, curiously, it does have a notion of a labeled statement too.

children=[
Child('LabelName', kind='IdentifierToken',
is_optional=True),
Child('LabelColon', kind='ColonToken',
is_optional=True),
Child('WhileKeyword', kind='WhileToken'),
Child('Conditions', kind='ConditionElementList',
collection_element_name='Condition'),
Expand Down Expand Up @@ -46,12 +50,8 @@

# repeat-while-stmt -> label? ':'? 'repeat' code-block 'while' expr ';'?
Node('RepeatWhileStmt', kind='Stmt',
traits=['WithCodeBlock', 'Labeled'],
traits=['WithCodeBlock'],
children=[
Child('LabelName', kind='IdentifierToken',
is_optional=True),
Child('LabelColon', kind='ColonToken',
is_optional=True),
Child('RepeatKeyword', kind='RepeatToken'),
Child('Body', kind='CodeBlock'),
Child('WhileKeyword', kind='WhileToken'),
Expand Down Expand Up @@ -79,12 +79,8 @@
# 'for' 'try'? 'await'? 'case'? pattern 'in' expr 'where'?
# expr code-block ';'?
Node('ForInStmt', kind='Stmt',
traits=['WithCodeBlock', 'Labeled'],
traits=['WithCodeBlock'],
children=[
Child('LabelName', kind='IdentifierToken',
is_optional=True),
Child('LabelColon', kind='ColonToken',
is_optional=True),
Child('ForKeyword', kind='ForToken'),
Child('TryKeyword', kind='TryToken',
is_optional=True),
Expand All @@ -106,12 +102,8 @@
# switch-stmt -> identifier? ':'? 'switch' expr '{'
# switch-case-list '}' ';'?
Node('SwitchStmt', kind='Stmt',
traits=['Braced', 'Labeled'],
traits=['Braced'],
children=[
Child('LabelName', kind='IdentifierToken',
is_optional=True),
Child('LabelColon', kind='ColonToken',
is_optional=True),
Child('SwitchKeyword', kind='SwitchToken'),
Child('Expression', kind='Expr'),
Child('LeftBrace', kind='LeftBraceToken'),
Expand All @@ -127,12 +119,8 @@

# do-stmt -> identifier? ':'? 'do' code-block catch-clause-list ';'?
Node('DoStmt', kind='Stmt',
traits=['WithCodeBlock', 'Labeled'],
traits=['WithCodeBlock'],
children=[
Child('LabelName', kind='IdentifierToken',
is_optional=True),
Child('LabelColon', kind='ColonToken',
is_optional=True),
Child('DoKeyword', kind='DoToken'),
Child('Body', kind='CodeBlock'),
Child('CatchClauses', kind='CatchClauseList',
Expand Down Expand Up @@ -272,12 +260,8 @@
# if-stmt -> identifier? ':'? 'if' condition-list code-block
# else-clause ';'?
Node('IfStmt', kind='Stmt',
traits=['WithCodeBlock', 'Labeled'],
traits=['WithCodeBlock'],
children=[
Child('LabelName', kind='IdentifierToken',
is_optional=True),
Child('LabelColon', kind='ColonToken',
is_optional=True),
Child('IfKeyword', kind='IfToken'),
Child('Conditions', kind='ConditionElementList',
collection_element_name='Condition'),
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6 changes: 0 additions & 6 deletions utils/gyb_syntax_support/Traits.py
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Expand Up @@ -43,12 +43,6 @@ def __init__(self, trait_name, description=None, children=None):
Child('TrailingComma', kind='CommaToken', is_optional=True),
]),

Trait('Labeled',
children=[
Child('LabelName', kind='IdentifierToken', is_optional=True),
Child('LabelColon', kind='ColonToken', is_optional=True),
]),

Trait('WithStatements',
children=[
Child('Statements', kind='CodeBlockItemList'),
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