feat: support actions in CEL expr (#5529)

wolf4ood · web-flow · commit 76548ceb8a47 · 2026-03-03T15:40:11.000+01:00
diff --git a/core/common/cel-core/src/main/java/org/eclipse/edc/policy/cel/engine/CelExpressionEngineImpl.java b/core/common/cel-core/src/main/java/org/eclipse/edc/policy/cel/engine/CelExpressionEngineImpl.java
@@ -39,6 +39,7 @@
 import java.util.Map;
 import java.util.Set;
 import java.util.stream.Collectors;
+import java.util.stream.Stream;
 
 public class CelExpressionEngineImpl implements CelExpressionEngine {
 
@@ -77,8 +78,7 @@ public boolean canEvaluate(String leftOperand) {
 
     @Override
     public Set<String> evaluationScopes(String leftOperand) {
-        return fetch(leftOperand)
-                .stream()
+        return Stream.concat(fetch(leftOperand).stream(), fetchByAction(leftOperand).stream())
                 .flatMap(expr -> expr.getScopes().stream())
                 .collect(Collectors.toSet());
     }
@@ -147,6 +147,13 @@ private List<CelExpression> fetch(String leftOperand) {
 
     }
 
+    private List<CelExpression> fetchByAction(String action) {
+        return ctx.execute(() -> store.query(QuerySpec.Builder.newInstance()
+                .filter(Criterion.criterion("actions", "contains", action))
+                .build()));
+
+    }
+
     private Result<CelAbstractSyntaxTree> compile(String expression) {
         CelAbstractSyntaxTree ast;
         try {
diff --git a/core/common/cel-core/src/test/java/org/eclipse/edc/policy/cel/engine/CelExpressionEngineImplTest.java b/core/common/cel-core/src/test/java/org/eclipse/edc/policy/cel/engine/CelExpressionEngineImplTest.java
@@ -29,6 +29,7 @@
 
 import java.util.List;
 import java.util.Map;
+import java.util.Set;
 import java.util.stream.Stream;
 
 import static org.assertj.core.api.Assertions.assertThat;
@@ -228,12 +229,25 @@ void canEvaluate_noMatching() {
         assertThat(result).isFalse();
     }
 
+    @Test
+    void evaluationScopes() {
+        var expr = expressionBuilder("empty").scopes(Set.of("scope1", "scope2")).build();
+        when(store.query(any())).thenReturn(List.of(expr));
+
+        var result = registry.evaluationScopes("leftOperand");
+
+        assertThat(result).containsAll(expr.getScopes());
+    }
+
     private CelExpression expression(String expr) {
+        return expressionBuilder(expr).build();
+    }
+
+    private CelExpression.Builder expressionBuilder(String expr) {
         return CelExpression.Builder.newInstance().id("id")
                 .leftOperand("test")
                 .expression(expr)
-                .description("description")
-                .build();
+                .description("description");
     }
 
     private @NotNull Map<String, Object> credential() {
diff --git a/core/common/lib/json-ld-lib/src/main/resources/document/management-context-v2.jsonld b/core/common/lib/json-ld-lib/src/main/resources/document/management-context-v2.jsonld
@@ -497,6 +497,10 @@
           "@id": "edc:scopes",
           "@container": "@set"
         },
+        "actions": {
+          "@id": "edc:actions",
+          "@container": "@set"
+        },
         "expression": "edc:expression",
         "description": "edc:description"
       }
diff --git a/core/control-plane/control-plane-transform/src/main/java/org/eclipse/edc/connector/controlplane/transform/edc/cel/from/JsonObjectFromCelExpressionTransformer.java b/core/control-plane/control-plane-transform/src/main/java/org/eclipse/edc/connector/controlplane/transform/edc/cel/from/JsonObjectFromCelExpressionTransformer.java
@@ -25,6 +25,7 @@
 
 import static org.eclipse.edc.jsonld.spi.JsonLdKeywords.ID;
 import static org.eclipse.edc.jsonld.spi.JsonLdKeywords.TYPE;
+import static org.eclipse.edc.policy.cel.model.CelExpression.CEL_EXPRESSION_ACTIONS_IRI;
 import static org.eclipse.edc.policy.cel.model.CelExpression.CEL_EXPRESSION_DESCRIPTION_IRI;
 import static org.eclipse.edc.policy.cel.model.CelExpression.CEL_EXPRESSION_EXPRESSION_IRI;
 import static org.eclipse.edc.policy.cel.model.CelExpression.CEL_EXPRESSION_LEFT_OPERAND_IRI;
@@ -49,6 +50,7 @@ public JsonObjectFromCelExpressionTransformer(JsonBuilderFactory factory) {
                 .add(CEL_EXPRESSION_EXPRESSION_IRI, celExpression.getExpression())
                 .add(CEL_EXPRESSION_DESCRIPTION_IRI, celExpression.getDescription())
                 .add(CEL_EXPRESSION_SCOPES_IRI, Json.createArrayBuilder(celExpression.getScopes()))
+                .add(CEL_EXPRESSION_ACTIONS_IRI, Json.createArrayBuilder(celExpression.getActions()))
                 .build();
     }
 }
diff --git a/core/control-plane/control-plane-transform/src/main/java/org/eclipse/edc/connector/controlplane/transform/edc/cel/to/JsonObjectToCelExpressionTransformer.java b/core/control-plane/control-plane-transform/src/main/java/org/eclipse/edc/connector/controlplane/transform/edc/cel/to/JsonObjectToCelExpressionTransformer.java
@@ -25,6 +25,7 @@
 import java.util.UUID;
 
 import static java.util.Optional.ofNullable;
+import static org.eclipse.edc.policy.cel.model.CelExpression.CEL_EXPRESSION_ACTIONS_IRI;
 import static org.eclipse.edc.policy.cel.model.CelExpression.CEL_EXPRESSION_DESCRIPTION_IRI;
 import static org.eclipse.edc.policy.cel.model.CelExpression.CEL_EXPRESSION_EXPRESSION_IRI;
 import static org.eclipse.edc.policy.cel.model.CelExpression.CEL_EXPRESSION_LEFT_OPERAND_IRI;
@@ -45,6 +46,7 @@ public JsonObjectToCelExpressionTransformer() {
             id = UUID.randomUUID().toString();
         }
         var scopes = new HashSet<String>();
+        var actions = new HashSet<String>();
 
         var operandLeft = transformString(object.get(CEL_EXPRESSION_LEFT_OPERAND_IRI), context);
         var expression = transformString(object.get(CEL_EXPRESSION_EXPRESSION_IRI), context);
@@ -53,12 +55,16 @@ public JsonObjectToCelExpressionTransformer() {
         ofNullable(object.getJsonArray(CEL_EXPRESSION_SCOPES_IRI))
                 .ifPresent(ja -> scopes.addAll(ja.stream().map(this::nodeValue).toList()));
 
+        ofNullable(object.getJsonArray(CEL_EXPRESSION_ACTIONS_IRI))
+                .ifPresent(ja -> actions.addAll(ja.stream().map(this::nodeValue).toList()));
+
         return CelExpression.Builder.newInstance()
                 .id(id)
                 .scopes(scopes)
                 .leftOperand(operandLeft)
                 .expression(expression)
                 .description(description)
+                .actions(actions)
                 .build();
     }
 }
diff --git a/core/control-plane/control-plane-transform/src/test/java/org/eclipse/edc/connector/controlplane/transform/edc/cel/from/JsonObjectFromCelExpressionTransformerTest.java b/core/control-plane/control-plane-transform/src/test/java/org/eclipse/edc/connector/controlplane/transform/edc/cel/from/JsonObjectFromCelExpressionTransformerTest.java
@@ -25,6 +25,7 @@
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.eclipse.edc.jsonld.spi.JsonLdKeywords.ID;
 import static org.eclipse.edc.jsonld.spi.JsonLdKeywords.TYPE;
+import static org.eclipse.edc.policy.cel.model.CelExpression.CEL_EXPRESSION_ACTIONS_IRI;
 import static org.eclipse.edc.policy.cel.model.CelExpression.CEL_EXPRESSION_DESCRIPTION_IRI;
 import static org.eclipse.edc.policy.cel.model.CelExpression.CEL_EXPRESSION_EXPRESSION_IRI;
 import static org.eclipse.edc.policy.cel.model.CelExpression.CEL_EXPRESSION_LEFT_OPERAND_IRI;
@@ -52,6 +53,7 @@ void transform_shouldConvertCelExpressionToJsonObject() {
                 .expression("== 'admin'")
                 .description("Check if user is admin")
                 .scopes(Set.of("read", "write"))
+                .actions(Set.of("use", "access"))
                 .build();
 
         var result = transformer.transform(celExpression, context);
@@ -65,6 +67,10 @@ void transform_shouldConvertCelExpressionToJsonObject() {
         assertThat(result.getJsonArray(CEL_EXPRESSION_SCOPES_IRI))
                 .hasSize(2)
                 .containsExactlyInAnyOrder(Json.createValue("read"), Json.createValue("write"));
+
+        assertThat(result.getJsonArray(CEL_EXPRESSION_ACTIONS_IRI))
+                .hasSize(2)
+                .containsExactlyInAnyOrder(Json.createValue("use"), Json.createValue("access"));
     }
 
     @Test
diff --git a/core/control-plane/control-plane-transform/src/test/java/org/eclipse/edc/connector/controlplane/transform/edc/cel/to/JsonObjectToCelExpressionTransformerTest.java b/core/control-plane/control-plane-transform/src/test/java/org/eclipse/edc/connector/controlplane/transform/edc/cel/to/JsonObjectToCelExpressionTransformerTest.java
@@ -22,6 +22,7 @@
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.eclipse.edc.jsonld.spi.JsonLdKeywords.ID;
 import static org.eclipse.edc.jsonld.spi.JsonLdKeywords.VALUE;
+import static org.eclipse.edc.policy.cel.model.CelExpression.CEL_EXPRESSION_ACTIONS_IRI;
 import static org.eclipse.edc.policy.cel.model.CelExpression.CEL_EXPRESSION_DESCRIPTION_IRI;
 import static org.eclipse.edc.policy.cel.model.CelExpression.CEL_EXPRESSION_EXPRESSION_IRI;
 import static org.eclipse.edc.policy.cel.model.CelExpression.CEL_EXPRESSION_LEFT_OPERAND_IRI;
@@ -50,6 +51,9 @@ void transform_shouldConvertJsonObjectToCelExpression() {
                 .add(CEL_EXPRESSION_SCOPES_IRI, Json.createArrayBuilder()
                         .add(Json.createObjectBuilder().add(VALUE, "read"))
                         .add(Json.createObjectBuilder().add(VALUE, "write")))
+                .add(CEL_EXPRESSION_ACTIONS_IRI, Json.createArrayBuilder()
+                        .add(Json.createObjectBuilder().add(VALUE, "use"))
+                        .add(Json.createObjectBuilder().add(VALUE, "access")))
                 .build();
 
         var result = transformer.transform(json, context);
@@ -60,6 +64,7 @@ void transform_shouldConvertJsonObjectToCelExpression() {
         assertThat(result.getExpression()).isEqualTo("== 'admin'");
         assertThat(result.getDescription()).isEqualTo("Check if user is admin");
         assertThat(result.getScopes()).containsExactlyInAnyOrder("read", "write");
+        assertThat(result.getActions()).containsExactlyInAnyOrder("use", "access");
     }
 
     @Test
diff --git a/extensions/common/api/management-api-schema-validator/src/main/resources/schema/management/v4/cel-expression-schema.json b/extensions/common/api/management-api-schema-validator/src/main/resources/schema/management/v4/cel-expression-schema.json
@@ -37,6 +37,13 @@
             "type": "string"
           },
           "uniqueItems": true
+        },
+        "actions": {
+          "type": "array",
+          "items": {
+            "type": "string"
+          },
+          "uniqueItems": true
         }
       },
       "required": [
diff --git a/extensions/common/store/sql/cel-store-sql/src/main/java/org/eclipse/edc/policy/cel/store/sql/BaseSqlDialectStatementsConfig.java b/extensions/common/store/sql/cel-store-sql/src/main/java/org/eclipse/edc/policy/cel/store/sql/BaseSqlDialectStatementsConfig.java
@@ -31,6 +31,7 @@ public String getInsertTemplate() {
                 .column(getExpressionColumn())
                 .column(getDescriptionColumn())
                 .jsonColumn(getScopesColumn())
+                .jsonColumn(getActionsColumn())
                 .column(getCreateTimestampColumn())
                 .column(getLastModifiedTimestampColumn())
                 .insertInto(getCelExpressionTable());
@@ -43,6 +44,7 @@ public String getUpdateTemplate() {
                 .column(getExpressionColumn())
                 .column(getDescriptionColumn())
                 .jsonColumn(getScopesColumn())
+                .jsonColumn(getActionsColumn())
                 .column(getCreateTimestampColumn())
                 .column(getLastModifiedTimestampColumn())
                 .update(getCelExpressionTable(), getIdColumn());
diff --git a/extensions/common/store/sql/cel-store-sql/src/main/java/org/eclipse/edc/policy/cel/store/sql/CelExpressionStoreStatements.java b/extensions/common/store/sql/cel-store-sql/src/main/java/org/eclipse/edc/policy/cel/store/sql/CelExpressionStoreStatements.java
@@ -44,6 +44,10 @@ default String getScopesColumn() {
         return "scopes";
     }
 
+    default String getActionsColumn() {
+        return "actions";
+    }
+
     default String getLeftOperandColumn() {
         return "left_operand";
     }
diff --git a/extensions/common/store/sql/cel-store-sql/src/main/java/org/eclipse/edc/policy/cel/store/sql/SqlCelExpressionStore.java b/extensions/common/store/sql/cel-store-sql/src/main/java/org/eclipse/edc/policy/cel/store/sql/SqlCelExpressionStore.java
@@ -57,6 +57,7 @@ public SqlCelExpressionStore(DataSourceRegistry dataSourceRegistry,
     private CelExpression mapResultSet(ResultSet resultSet) throws Exception {
         var id = resultSet.getString(statements.getIdColumn());
         List<String> scopes = fromJson(resultSet.getString(statements.getScopesColumn()), getTypeRef());
+        List<String> actions = fromJson(resultSet.getString(statements.getActionsColumn()), getTypeRef());
         var leftOperand = resultSet.getString(statements.getLeftOperandColumn());
         var expression = resultSet.getString(statements.getExpressionColumn());
         var description = resultSet.getString(statements.getDescriptionColumn());
@@ -71,6 +72,7 @@ private CelExpression mapResultSet(ResultSet resultSet) throws Exception {
                 .description(description)
                 .createdAt(created)
                 .updatedAt(lastModified)
+                .actions(new HashSet<>(actions))
                 .build();
     }
 
@@ -89,6 +91,7 @@ public StoreResult<Void> create(CelExpression expression) {
                         expression.getExpression(),
                         expression.getDescription(),
                         toJson(expression.getScopes()),
+                        toJson(expression.getActions()),
                         expression.getCreatedAt(),
                         expression.getUpdatedAt()
                 );
@@ -111,6 +114,7 @@ public StoreResult<Void> update(CelExpression expression) {
                             expression.getExpression(),
                             expression.getDescription(),
                             toJson(expression.getScopes()),
+                            toJson(expression.getActions()),
                             expression.getCreatedAt(),
                             expression.getUpdatedAt(),
                             expression.getId());
diff --git a/extensions/common/store/sql/cel-store-sql/src/main/java/org/eclipse/edc/policy/cel/store/sql/postgres/CelExpressionMapping.java b/extensions/common/store/sql/cel-store-sql/src/main/java/org/eclipse/edc/policy/cel/store/sql/postgres/CelExpressionMapping.java
@@ -15,6 +15,7 @@
 package org.eclipse.edc.policy.cel.store.sql.postgres;
 
 import org.eclipse.edc.policy.cel.store.sql.CelExpressionStoreStatements;
+import org.eclipse.edc.sql.translation.JsonArrayTranslator;
 import org.eclipse.edc.sql.translation.TranslationMapping;
 
 
@@ -28,6 +29,7 @@ public class CelExpressionMapping extends TranslationMapping {
     public static final String FIELD_LEFT_OPERAND = "leftOperand";
     public static final String FIELD_DESCRIPTION = "description";
     public static final String FIELD_EXPRESSION = "expression";
+    public static final String FIELD_ACTIONS = "actions";
     public static final String FIELD_LASTMODIFIED_TIMESTAMP = "lastModified";
 
     public CelExpressionMapping(CelExpressionStoreStatements statements) {
@@ -36,6 +38,7 @@ public CelExpressionMapping(CelExpressionStoreStatements statements) {
         add(FIELD_DESCRIPTION, statements.getDescriptionColumn());
         add(FIELD_EXPRESSION, statements.getExpressionColumn());
         add(FIELD_CREATE_TIMESTAMP, statements.getCreateTimestampColumn());
+        add(FIELD_ACTIONS, new JsonArrayTranslator(statements.getActionsColumn()));
         add(FIELD_LASTMODIFIED_TIMESTAMP, statements.getLastModifiedTimestampColumn());
     }
 }
diff --git a/extensions/common/store/sql/cel-store-sql/src/main/resources/cel-expression-schema.sql b/extensions/common/store/sql/cel-store-sql/src/main/resources/cel-expression-schema.sql
@@ -16,10 +16,11 @@
 CREATE TABLE IF NOT EXISTS edc_cel_expression
 (
     id VARCHAR PRIMARY KEY NOT NULL, -- ID
-    scopes                 JSON DEFAULT '{}',
+    scopes                 JSON DEFAULT '[]',
     left_operand           TEXT NOT NULL,
     expression             TEXT NOT NULL,
     description            TEXT NOT NULL,
+    actions                JSON DEFAULT '[]',
     created_date           BIGINT              NOT NULL, -- POSIX timestamp of the creation of the PC
     last_modified_date     BIGINT              NOT NULL       -- POSIX timestamp of the last modified date
 );
diff --git a/spi/common/cel-spi/src/main/java/org/eclipse/edc/policy/cel/model/CelExpression.java b/spi/common/cel-spi/src/main/java/org/eclipse/edc/policy/cel/model/CelExpression.java
@@ -38,12 +38,16 @@ public class CelExpression extends Entity {
     public static final String CEL_EXPRESSION_EXPRESSION_IRI = EDC_NAMESPACE + CEL_EXPRESSION_EXPRESSION_TERM;
     public static final String CEL_EXPRESSION_DESCRIPTION_TERM = "description";
     public static final String CEL_EXPRESSION_DESCRIPTION_IRI = EDC_NAMESPACE + CEL_EXPRESSION_DESCRIPTION_TERM;
+    public static final String CEL_EXPRESSION_ACTIONS_TERM = "actions";
+    public static final String CEL_EXPRESSION_ACTIONS_IRI = EDC_NAMESPACE + CEL_EXPRESSION_ACTIONS_TERM;
     public static final String MATCH_ALL_SCOPE = "*.";
 
     private Set<String> scopes = new HashSet<>();
     private String leftOperand;
     private String expression;
     private String description;
+    private Set<String> actions = new HashSet<>();
+
     private long updatedAt;
 
 
@@ -54,6 +58,10 @@ public Set<String> getScopes() {
         return scopes;
     }
 
+    public Set<String> getActions() {
+        return actions;
+    }
+
     public String getDescription() {
         return description;
     }
@@ -90,6 +98,11 @@ public Builder scopes(Set<String> scopes) {
             return this;
         }
 
+        public Builder actions(Set<String> actions) {
+            entity.actions = actions;
+            return this;
+        }
+
         public Builder leftOperand(String leftOperand) {
             entity.leftOperand = leftOperand;
             return this;
diff --git a/spi/common/cel-spi/src/testFixtures/java/org/eclipse/edc/policy/cel/store/CelExpressionStoreTestBase.java b/spi/common/cel-spi/src/testFixtures/java/org/eclipse/edc/policy/cel/store/CelExpressionStoreTestBase.java
@@ -19,6 +19,8 @@
 import org.eclipse.edc.spi.query.QuerySpec;
 import org.junit.jupiter.api.Test;
 
+import java.util.Set;
+
 import static java.util.stream.IntStream.range;
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.eclipse.edc.junit.assertions.AbstractResultAssert.assertThat;
@@ -75,6 +77,21 @@ void query_leftOperand() {
                 });
     }
 
+    @Test
+    void query_action() {
+        var resources = range(0, 5)
+                .mapToObj(i -> celExpression("id" + i, "leftOperand" + i, "action" + i))
+                .toList();
+
+        resources.forEach(getStore()::create);
+
+        var res = getStore().query(QuerySpec.Builder.newInstance().filter(Criterion.criterion("actions", "contains", "action3")).build());
+        assertThat(res).hasSize(1)
+                .first().satisfies(celExpression -> {
+                    assertThat(celExpression).usingRecursiveComparison().isEqualTo(resources.get(3));
+                });
+    }
+
     @Test
     void query_whenNotFound() {
         var resources = range(0, 5)
@@ -147,11 +164,16 @@ private CelExpression celExpression(String id) {
         return celExpression(id, "leftOperand");
     }
 
-    private CelExpression celExpression(String id, String leftOperand) {
+    private CelExpression celExpression(String id, String leftOperand, String action) {
         return CelExpression.Builder.newInstance().id(id)
                 .leftOperand(leftOperand)
                 .expression("expression")
                 .description("description")
+                .actions(Set.of(action))
                 .build();
     }
+
+    private CelExpression celExpression(String id, String leftOperand) {
+        return celExpression(id, leftOperand, "action");
+    }
 }
diff --git a/system-tests/e2e-transfer-test/runner/build.gradle.kts b/system-tests/e2e-transfer-test/runner/build.gradle.kts
@@ -18,6 +18,7 @@ plugins {
 
 dependencies {
     testImplementation(project(":spi:control-plane:transfer-spi"))
+    testImplementation(project(":spi:common:cel-spi"))
     testImplementation(project(":spi:data-plane:data-plane-spi"))
     testImplementation(project(":extensions:common:sql:sql-core"))
     testImplementation(project(":extensions:common:transaction:transaction-local"))
diff --git a/system-tests/e2e-transfer-test/runner/src/test/java/org/eclipse/edc/test/e2e/negotiation/ContractNegotiationEndToEndTest.java b/system-tests/e2e-transfer-test/runner/src/test/java/org/eclipse/edc/test/e2e/negotiation/ContractNegotiationEndToEndTest.java
diff --git a/system-tests/management-api/management-api-test-runner/src/test/java/org/eclipse/edc/test/e2e/managementapi/TestFunctions.java b/system-tests/management-api/management-api-test-runner/src/test/java/org/eclipse/edc/test/e2e/managementapi/TestFunctions.java

Original file line number	Diff line number	Diff line change
`@@ -25,6 +25,7 @@`
`25`	`25`
`26`	`26`	`import static org.eclipse.edc.jsonld.spi.JsonLdKeywords.ID;`
`27`	`27`	`import static org.eclipse.edc.jsonld.spi.JsonLdKeywords.TYPE;`
	`28`	`+import static org.eclipse.edc.policy.cel.model.CelExpression.CEL_EXPRESSION_ACTIONS_IRI;`
`28`	`29`	`import static org.eclipse.edc.policy.cel.model.CelExpression.CEL_EXPRESSION_DESCRIPTION_IRI;`
`29`	`30`	`import static org.eclipse.edc.policy.cel.model.CelExpression.CEL_EXPRESSION_EXPRESSION_IRI;`
`30`	`31`	`import static org.eclipse.edc.policy.cel.model.CelExpression.CEL_EXPRESSION_LEFT_OPERAND_IRI;`
`@@ -49,6 +50,7 @@ public JsonObjectFromCelExpressionTransformer(JsonBuilderFactory factory) {`
`49`	`50`	`.add(CEL_EXPRESSION_EXPRESSION_IRI, celExpression.getExpression())`
`50`	`51`	`.add(CEL_EXPRESSION_DESCRIPTION_IRI, celExpression.getDescription())`
`51`	`52`	`.add(CEL_EXPRESSION_SCOPES_IRI, Json.createArrayBuilder(celExpression.getScopes()))`
	`53`	`+ .add(CEL_EXPRESSION_ACTIONS_IRI, Json.createArrayBuilder(celExpression.getActions()))`
`52`	`54`	`.build();`
`53`	`55`	`}`
`54`	`56`	`}`
Original file line number	Diff line number	Diff line change
`@@ -44,6 +44,10 @@ default String getScopesColumn() {`
`44`	`44`	`return "scopes";`
`45`	`45`	`}`
`46`	`46`
	`47`	`+ default String getActionsColumn() {`
	`48`	`+ return "actions";`
	`49`	`+ }`
	`50`	`+`
`47`	`51`	`default String getLeftOperandColumn() {`
`48`	`52`	`return "left_operand";`
`49`	`53`	`}`