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GROOVY-12173: Left-factor parser rules to reduce lookahead on hot parse paths #2720

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Merged
daniellansun merged 1 commit into from
Jul 18, 2026
+412 −39
Merged

GROOVY-12173: Left-factor parser rules to reduce lookahead on hot parse paths #2720

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50 changes: 31 additions & 19 deletions src/antlr/GroovyParser.g4
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Original file line number Diff line number Diff line change
Expand Up @@ -118,8 +118,10 @@ packageDeclaration
;

importDeclaration
: annotationsOpt IMPORT STATIC? qualifiedName (DOT MUL | AS alias=identifier)?
| annotationsOpt IMPORT MODULE qualifiedName
: annotationsOpt IMPORT
( MODULE qualifiedName
| STATIC? qualifiedName (DOT MUL | AS alias=identifier)?
)
;


Expand Down Expand Up @@ -557,8 +559,7 @@ block
;

blockStatement
: localVariableDeclaration
| statement
: statement
;

localVariableDeclaration
Expand All @@ -579,8 +580,11 @@ variableDeclaration[int t]
;

typeNamePairs
: LPAREN typeNamePair (COMMA typeNamePair)* RPAREN
| LPAREN keyedPair (COMMA keyedPair)* RPAREN
: LPAREN
( typeNamePair (COMMA typeNamePair)*
| keyedPair (COMMA keyedPair)*
)
RPAREN
;

typeNamePair
Expand Down Expand Up @@ -978,21 +982,29 @@ pathExpression returns [int t]
pathElement returns [int t]
: nls
(
DOT nls NEW creator[1]
{ $t = 6; }
|
// AT: foo.@bar selects the field (or attribute), not property
(
( DOT // The all-powerful dot.
| SPREAD_DOT // Spread operator: x*.y === x?.collect{it.y}
| SAFE_DOT // Optional-null operator: x?.y === (x==null)?null:x.y
| SAFE_CHAIN_DOT // Optional-null chain operator: x??.y.z === x?.y?.z
) nls (AT | nonWildcardTypeArguments)?
|
METHOD_POINTER nls // Method pointer operator: foo.&y == foo.metaClass.getMethodPointer(foo, "y")
DOT nls
( NEW creator[1]
{ $t = 6; }
|
METHOD_REFERENCE nls (nonWildcardTypeArguments)? // Method reference: System.out::println
// AT: foo.@bar selects the field (or attribute), not property
(AT | nonWildcardTypeArguments)?
namePart
{ $t = 1; }
)
|
// Non-DOT member selection operators (still share namePart tail)
( SPREAD_DOT // Spread operator: x*.y === x?.collect{it.y}
| SAFE_DOT // Optional-null operator: x?.y === (x==null)?null:x.y
| SAFE_CHAIN_DOT // Optional-null chain operator: x??.y.z === x?.y?.z
) nls (AT | nonWildcardTypeArguments)?
namePart
{ $t = 1; }
|
METHOD_POINTER nls // Method pointer operator: foo.&y == foo.metaClass.getMethodPointer(foo, "y")
namePart
{ $t = 1; }
|
METHOD_REFERENCE nls (nonWildcardTypeArguments)? // Method reference: System.out::println
namePart
{ $t = 1; }

Expand Down
32 changes: 12 additions & 20 deletions src/main/java/org/apache/groovy/parser/antlr4/AstBuilder.java
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Expand Up @@ -3440,7 +3440,7 @@
// } primary ---------------------------------------------------------------

@Override
public Expression visitCreator(final CreatorContext ctx) {

Check warning on line 3443 in src/main/java/org/apache/groovy/parser/antlr4/AstBuilder.java

View check run for this annotation

SonarQubeCloud / SonarCloud Code Analysis

A "Brain Method" was detected. Refactor it to reduce at least one of the following metrics: LOC from 70 to 64, Complexity from 17 to 14, Nesting Level from 3 to 2, Number of Variables from 24 to 6. 


See more on https://sonarcloud.io/project/issues?id=apache_groovy&issues=AZ9045NDGPmZJSHOvOgU&open=AZ9045NDGPmZJSHOvOgU&pullRequest=2720
ClassNode classNode = this.visitCreatedName(ctx.createdName());

if (asBoolean(ctx.arguments())) { // create instance of class
Expand Down Expand Up @@ -4351,29 +4351,21 @@

@Override
public Statement visitBlockStatement(final BlockStatementContext ctx) {
if (asBoolean(ctx.localVariableDeclaration())) {
return configureAST(this.visitLocalVariableDeclaration(ctx.localVariableDeclaration()), ctx);
}

if (asBoolean(ctx.statement())) {
Object astNode = this.visit(ctx.statement()); //this.configureAST((Statement) this.visit(ctx.statement()), ctx);

if (null == astNode) {
return null;
}
Object astNode = this.visit(ctx.statement());

if (astNode instanceof Statement) {
return (Statement) astNode;
} else if (astNode instanceof MethodNode) {
throw createParsingFailedException("Method definition not expected here", ctx);
} else if (astNode instanceof ImportNode) {
throw createParsingFailedException("Import statement not expected here", ctx);
} else {
throw createParsingFailedException("The statement(" + astNode.getClass() + ") not expected here", ctx);
}
if (null == astNode) {
return null;
}

throw createParsingFailedException("Unsupported block statement: " + ctx.getText(), ctx);
if (astNode instanceof Statement) {
return (Statement) astNode;
} else if (astNode instanceof MethodNode) {
throw createParsingFailedException("Method definition not expected here", ctx);
} else if (astNode instanceof ImportNode) {
throw createParsingFailedException("Import statement not expected here", ctx);
} else {
throw createParsingFailedException("The statement(" + astNode.getClass() + ") not expected here", ctx);
}
}

@Override
Expand Down
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