Replace ANTLR parser with CongoCC

README.md

@@ -420,7 +420,7 @@ Native-image and package behavior must be verified in the consuming application'
 prove Quarkus native-image or package compatibility for every application.
 
 Before using CEL conditions in release-critical authorization paths, run JVM condition tests, the
-consuming project's normal build, dependency tree review for protobuf/ANTLR/Jackson conflicts, and
+consuming project's normal build, dependency tree review for protobuf/Jackson conflicts, and
 package/native-image verification if native execution is part of the release path.
 
 ### Not yet implemented

bom/build.gradle.kts

@@ -24,7 +24,6 @@ plugins {
 dependencies {
   constraints {
     api(project(":cel-core"))
-    api(project(":cel-generated-antlr"))
     api(project(":cel-generated-pb"))
     api(project(":cel-generated-pb3"))
     api(project(":cel-conformance"))

build.gradle.kts

@@ -102,7 +102,6 @@ idea.project.settings {
     afterSync(
       ":cel-generated-pb:jar",
       ":cel-generated-pb:testJar",
-      ":cel-generated-antlr:shadowJar",
     )
   }
 }

core/build.gradle.kts

@@ -24,14 +24,17 @@ plugins {
   `java-test-fixtures`
 }
 
+val congocc = configurations.create("congocc")
+
 configurations.named("jmhImplementation") { extendsFrom(configurations.testFixturesApi.get()) }
 
 dependencies {
-  implementation(project(":cel-generated-antlr"))
   compileOnly(project(":cel-generated-pb"))
 
   implementation(libs.agrona)
 
+  congocc(libs.congocc)
+
   testImplementation(project(":cel-generated-pb"))
   testFixturesApi(platform(libs.junit.bom))
   testFixturesApi(libs.bundles.junit.testing)
@@ -46,13 +49,59 @@ dependencies {
   jmhAnnotationProcessor(libs.jmh.generator.annprocess)
 }
 
+abstract class Generate : JavaExec() {
+  init {
+    outputs.cacheIf { true }
+  }
+
+  @get:InputDirectory
+  @get:PathSensitive(PathSensitivity.RELATIVE)
+  abstract val sourceDir: DirectoryProperty
+
+  @get:OutputDirectory abstract val outputDir: DirectoryProperty
+}
+
+val generateCelGrammar =
+  tasks.register<Generate>("generateCelGrammar") {
+    val generatedDir = layout.buildDirectory.dir("generated/sources/congocc/cel")
+    val projectDir = layout.projectDirectory
+
+    sourceDir = projectDir.dir("src/main/congocc/cel")
+    outputDir = generatedDir
+
+    classpath(congocc)
+    mainClass = "org.congocc.app.Main"
+    workingDir(projectDir)
+
+    doFirst { generatedDir.get().asFile.deleteRecursively() }
+
+    argumentProviders.add(
+      CommandLineArgumentProvider {
+        val sourceFile = sourceDir.file("cel-java.ccc").get().asFile.relativeTo(projectDir.asFile)
+        val base =
+          listOf(
+            "-d",
+            generatedDir.get().asFile.toString(),
+            "-jdk17",
+            "-n",
+            sourceFile.toString(),
+          )
+        if (logger.isInfoEnabled) base else base + "-q"
+      }
+    )
+  }
+
 jmh { jmhVersion.set(libs.versions.jmh.get()) }
 
+sourceSets.main { java.srcDir(generateCelGrammar) }
+
 sourceSets.test {
   java.srcDir(layout.buildDirectory.dir("generated/source/proto/test/java"))
   java.destinationDirectory.set(layout.buildDirectory.dir("classes/java/generatedTest"))
 }
 
+tasks.named("compileJava") { dependsOn(generateCelGrammar) }
+
 tasks.named("check") { dependsOn(tasks.named("jmh")) }
 
 tasks.named("assemble") { dependsOn(tasks.named("jmhJar")) }

core/src/main/congocc/cel/cel-java.ccc

@@ -0,0 +1,151 @@
+/*
+ * Copyright (C) 2026 The Authors of CEL-Java
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+PARSER_PACKAGE="org.projectnessie.cel.parser";
+PARSER_CLASS=CelGrammarParser;
+LEXER_CLASS=CelGrammarLexer;
+NODE_PACKAGE="org.projectnessie.cel.parser.ast";
+
+INCLUDE "cel.ccc"
+
+INJECT PARSER_CLASS :
+{
+  private boolean nextTokenStartsExpression() {
+    TokenType type = getToken(1).getType();
+    return switch (type) {
+      case LBRACKET, LBRACE, LPAREN, DOT, MINUS, EXCLAM, TRUE, FALSE, NULL, NUM_UINT, NUM_FLOAT,
+          NUM_INT, STRING, BYTES, IDENTIFIER -> true;
+      default -> false;
+    };
+  }
+}
+
+INJECT ParseException :
+{
+  @SuppressWarnings("unchecked")
+  public java.util.Set<Token.TokenType> getExpectedTokenTypes() {
+    java.util.Set x = expectedTypes;
+    return x;
+  }
+}
+
+INJECT Expr : implements CelExprNode;
+INJECT Expr :
+{
+  @Override
+  public com.google.api.expr.v1alpha1.Expr toCelExpr(CelExprBuilder builder) {
+    return builder.visitExpr(this);
+  }
+}
+
+INJECT ConditionalOr : implements CelExprNode;
+INJECT ConditionalOr :
+{
+  @Override
+  public com.google.api.expr.v1alpha1.Expr toCelExpr(CelExprBuilder builder) {
+    return builder.visitBalanced(this, org.projectnessie.cel.common.operators.Operator.LogicalOr);
+  }
+}
+
+INJECT ConditionalAnd : implements CelExprNode;
+INJECT ConditionalAnd :
+{
+  @Override
+  public com.google.api.expr.v1alpha1.Expr toCelExpr(CelExprBuilder builder) {
+    return builder.visitBalanced(this, org.projectnessie.cel.common.operators.Operator.LogicalAnd);
+  }
+}
+
+INJECT Relation : implements CelExprNode;
+INJECT Relation :
+{
+  @Override
+  public com.google.api.expr.v1alpha1.Expr toCelExpr(CelExprBuilder builder) {
+    return builder.visitBinary(this);
+  }
+}
+
+INJECT Calc : implements CelExprNode;
+INJECT Calc :
+{
+  @Override
+  public com.google.api.expr.v1alpha1.Expr toCelExpr(CelExprBuilder builder) {
+    return builder.visitBinary(this);
+  }
+}
+
+INJECT Multiplicative : implements CelExprNode;
+INJECT Multiplicative :
+{
+  @Override
+  public com.google.api.expr.v1alpha1.Expr toCelExpr(CelExprBuilder builder) {
+    return builder.visitBinary(this);
+  }
+}
+
+INJECT Unary : implements CelExprNode;
+INJECT Unary :
+{
+  @Override
+  public com.google.api.expr.v1alpha1.Expr toCelExpr(CelExprBuilder builder) {
+    return builder.visitUnary(this);
+  }
+}
+
+INJECT Member : implements CelExprNode;
+INJECT Member :
+{
+  @Override
+  public com.google.api.expr.v1alpha1.Expr toCelExpr(CelExprBuilder builder) {
+    return builder.visitMember(this);
+  }
+}
+
+INJECT Primary : implements CelExprNode;
+INJECT Primary :
+{
+  @Override
+  public com.google.api.expr.v1alpha1.Expr toCelExpr(CelExprBuilder builder) {
+    return builder.visitPrimary(this);
+  }
+}
+
+INJECT ConstantLiteral : implements CelExprNode;
+INJECT ConstantLiteral :
+{
+  @Override
+  public com.google.api.expr.v1alpha1.Expr toCelExpr(CelExprBuilder builder) {
+    return builder.visitLiteral(this);
+  }
+}
+
+INJECT Literal : implements CelExprNode;
+INJECT Literal :
+{
+  @Override
+  public com.google.api.expr.v1alpha1.Expr toCelExpr(CelExprBuilder builder) {
+    return builder.visitLiteral(this);
+  }
+}
+
+INJECT Identifier : implements CelExprNode;
+INJECT Identifier :
+{
+  @Override
+  public com.google.api.expr.v1alpha1.Expr toCelExpr(CelExprBuilder builder) {
+    return builder.visitIdentifier(this);
+  }
+}

core/src/main/congocc/cel/cel-lexer.ccc

@@ -0,0 +1,84 @@
+/*
+ * Copyright (C) 2026 The Authors of CEL-Java
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+SKIP : <WHITESPACE : (" " | "\t" | "\r" | "\n" | "\f")+> #Whitespace;
+
+UNPARSED : <COMMENT : "//" (~["\n"])*> #Comment;
+
+TOKEN #Operator :
+    <EQUALS : "==">
+  | <NOT_EQUALS : "!=">
+  | <LESS_EQUALS : "<=">
+  | <GREATER_EQUALS : ">=">
+  | <LOGICAL_AND : "&&">
+  | <LOGICAL_OR : "||">
+  | <IN : "in">
+  | <LESS : "<">
+  | <GREATER : ">">
+  | <LBRACKET : "[">
+  | <RBRACKET : "]">
+  | <LBRACE : "{">
+  | <RBRACE : "}">
+  | <LPAREN : "(">
+  | <RPAREN : ")">
+  | <DOT : ".">
+  | <COMMA : ",">
+  | <MINUS : "-">
+  | <EXCLAM : "!">
+  | <QUESTIONMARK : "?">
+  | <COLON : ":">
+  | <PLUS : "+">
+  | <STAR : "*">
+  | <SLASH : "/">
+  | <PERCENT : "%">
+  ;
+
+TOKEN #Literal :
+    <TRUE : "true">
+  | <FALSE : "false">
+  | <NULL : "null">
+  | <#HEXDIGIT : ["0"-"9", "a"-"f", "A"-"F"]>
+  | <#DIGIT : ["0"-"9"]>
+  | <#EXPONENT : ["e", "E"] (["+", "-"])? (<DIGIT>)+>
+  | <NUM_UINT : ((<DIGIT>)+ | "0x" (<HEXDIGIT>)+) ["u", "U"]>
+  | <NUM_FLOAT : ((<DIGIT>)+ "." (<DIGIT>)+ (<EXPONENT>)? | (<DIGIT>)+ <EXPONENT> | "." (<DIGIT>)+ (<EXPONENT>)?)>
+  | <NUM_INT : (<DIGIT>)+ | "0x" (<HEXDIGIT>)+>
+  | <#ESC_CHAR_SEQ : "\\" ["a", "b", "f", "n", "r", "t", "v", "\"", "'", "\\", "?", "`"]>
+  | <#ESC_OCT_SEQ : "\\" ["0"-"3"] ["0"-"7"] ["0"-"7"]>
+  | <#ESC_BYTE_SEQ : "\\" ["x", "X"] <HEXDIGIT> <HEXDIGIT>>
+  | <#ESC_UNI_SEQ : "\\" "u" <HEXDIGIT> <HEXDIGIT> <HEXDIGIT> <HEXDIGIT> | "\\" "U" <HEXDIGIT> <HEXDIGIT> <HEXDIGIT> <HEXDIGIT> <HEXDIGIT> <HEXDIGIT> <HEXDIGIT> <HEXDIGIT>>
+  | <#ESC_SEQ : <ESC_CHAR_SEQ> | <ESC_BYTE_SEQ> | <ESC_UNI_SEQ> | <ESC_OCT_SEQ>>
+  | <#DQ_CHAR : <ESC_SEQ> | ~["\\", "\"", "\n", "\r"]>
+  | <#SQ_CHAR : <ESC_SEQ> | ~["\\", "'", "\n", "\r"]>
+  | <#TDQ_CHAR : <ESC_SEQ> | ~["\\"]>
+  | <#TSQ_CHAR : <ESC_SEQ> | ~["\\"]>
+  | <STRING :
+        "\"" (<DQ_CHAR>)* "\""
+      | "'" (<SQ_CHAR>)* "'"
+      | "\"\"\"" (<TDQ_CHAR>)* "\"\"\""
+      | "'''" (<TSQ_CHAR>)* "'''"
+      | ["r", "R"] "\"" (~["\"", "\n", "\r"])* "\""
+      | ["r", "R"] "'" (~["'", "\n", "\r"])* "'"
+      | ["r", "R"] "\"\"\"" (~[])* "\"\"\""
+      | ["r", "R"] "'''" (~[])* "'''"
+    >
+  | <BYTES : ["b", "B"] <STRING>>
+  ;
+
+TOKEN #Identifier :
+    <IDENTIFIER : ["A"-"Z", "a"-"z", "_"] (["A"-"Z", "a"-"z", "0"-"9", "_"])*>
+  | <ESC_IDENTIFIER : "`" (<ESC_SEQ> | ~["\\", "`", "\n", "\r"])* "`">
+  ;