sqlparser: Add explicit nodes for aliases

Author: simolus3

drift_dev/lib/src/analysis/resolver/queries/explicit_alias_transformer.dart

@@ -75,7 +75,7 @@ class ExplicitAliasTransformer extends Transformer<bool> {
       final name = '_c${_aliasCounter++}';
       _renamed[expr] = name;
       return super.visitExpressionResultColumn(
-        ExpressionResultColumn(expression: expr, as: name),
+        ExpressionResultColumn(expression: expr, as: AliasClause(name)),
         arg,
       );
     } else {
@@ -152,7 +152,7 @@ class ExplicitAliasTransformer extends Transformer<bool> {
   @override
   AstNode? visitTableReference(TableReference e, bool arg) {
     if (_renamedResultSets[e.availableResultSet] case final newName?) {
-      e.as = newName;
+      e.as = AliasClause(newName);
     }
 
     return super.visitTableReference(e, arg);
@@ -161,7 +161,7 @@ class ExplicitAliasTransformer extends Transformer<bool> {
   @override
   AstNode? visitTableValuedFunction(TableValuedFunction e, bool arg) {
     if (_renamedResultSets[e.availableResultSet] case final newName?) {
-      e.as = newName;
+      e.as = AliasClause(newName);
     }
 
     return super.visitTableValuedFunction(e, arg);
@@ -170,7 +170,7 @@ class ExplicitAliasTransformer extends Transformer<bool> {
   @override
   AstNode? visitSelectStatementAsSource(SelectStatementAsSource e, bool arg) {
     if (_renamedResultSets[e.availableResultSet] case final newName?) {
-      e.as = newName;
+      e.as = AliasClause(newName);
     }
 
     return super.visitSelectStatementAsSource(e, arg);

drift_dev/lib/src/analysis/resolver/queries/nested_queries.dart

@@ -132,7 +132,7 @@ class _AnalyzerState {
             entityName: variable.reference.entityName,
             columnName: variable.reference.columnName,
           ),
-          as: variable.helperColumn,
+          as: AliasClause(variable.helperColumn),
         ),
       );
     }

drift_dev/lib/src/analysis/resolver/queries/query_analyzer.dart

@@ -482,7 +482,7 @@ class QueryAnalyzer {
 
     return NestedResultTable(
       from: column,
-      name: column.as ?? column.tableName,
+      name: column.as?.name ?? column.tableName,
       innerResultSet: driftResultSet,
       nameForGeneratedRowClass: resultClassName,
       isNullable: isNullable,
@@ -512,8 +512,8 @@ class QueryAnalyzer {
     column.queryName = name;
 
     var resultClassName = ReCase(queryContext.queryName).pascalCase;
-    if (column.as != null) {
-      resultClassName += ReCase(column.as!).pascalCase;
+    if (column.as case final alias?) {
+      resultClassName += ReCase(alias.name).pascalCase;
     } else {
       resultClassName += 'NestedQuery$queryIndex';
     }

drift_dev/lib/src/analysis/results/query.dart

@@ -918,8 +918,8 @@ final class NestedResultQuery extends NestedResult {
   }
 
   String filedName() {
-    if (from.as != null) {
-      return from.as!;
+    if (from.as case final alias?) {
+      return alias.name;
     }
 
     return ReCase(query.name).camelCase;

sqlparser/CHANGELOG.md

@@ -5,6 +5,7 @@
 - In drift files, allow reading imports and statement metadata from comments.
 - Make `Queryable` and `TableOrSubquery` sealed classes, remove `Queryable.when`.
 - Expose tokens making up `Reference`s and `TableReference`s.
+- Turn `AS` clauses into an explicit AST node with better spans.
 
 ## 0.43.1
 

sqlparser/lib/src/analysis/steps/column_resolver.dart

@@ -51,7 +51,7 @@ class ColumnResolver extends RecursiveVisitor<ColumnResolverContext, void> {
 
     if (e.target case final UpdateTarget onUpdate) {
       onUpdate.scope = SingleTableReferenceScope(scope, e.onTable.tableName,
-          ResultSetAvailableInStatement(e.onTable, table, e.onTable.as));
+          ResultSetAvailableInStatement(e.onTable, table, e.onTable.as?.name));
     }
 
     visitChildren(e, arg);
@@ -164,7 +164,7 @@ class ColumnResolver extends RecursiveVisitor<ColumnResolverContext, void> {
       e.foreignTable.tableName,
       resolved != null
           ? ResultSetAvailableInStatement(
-              e.foreignTable, resolved, e.foreignTable.as)
+              e.foreignTable, resolved, e.foreignTable.as?.name)
           : null,
     );
     e.scope = scope;
@@ -303,7 +303,7 @@ class ColumnResolver extends RecursiveVisitor<ColumnResolverContext, void> {
           source,
           resultSet,
           switch (source) {
-            Renamable(as: final alias) => alias,
+            Renamable(as: final alias?) => alias.name,
             _ => null,
           });
 
@@ -318,13 +318,13 @@ class ColumnResolver extends RecursiveVisitor<ColumnResolverContext, void> {
       case final TableReference table:
         final resolved = _resolveTableReference(table, state);
         markAvailableResultSet(
-            table, resolved ?? table, table.as ?? table.tableName);
+            table, resolved ?? table, table.as?.name ?? table.tableName);
 
         if (resolved != null) {
           addColumns(table.resultSet!.resolvedColumns!);
         }
       case final SelectStatementAsSource select:
-        markAvailableResultSet(select, select.statement, select.as);
+        markAvailableResultSet(select, select.statement, select.as?.name);
 
         // Inside subqueries, references don't take the name of the referenced
         // column.
@@ -356,13 +356,14 @@ class ColumnResolver extends RecursiveVisitor<ColumnResolverContext, void> {
         if (resolved == null) {
           final table = scope.resolveResultSetToAdd(function.name);
           if (table is Table && table.isVirtual) {
-            resolved =
-                function.as != null ? TableAlias(table, function.as!) : table;
+            resolved = function.as != null
+                ? TableAlias(table, function.as!.name)
+                : table;
           }
         }
 
         markAvailableResultSet(
-            function, resolved ?? function, function.as ?? function.name);
+            function, resolved ?? function, function.as?.name ?? function.name);
 
         if (resolved == null) {
           context.reportError(AnalysisError(
@@ -445,7 +446,7 @@ class ColumnResolver extends RecursiveVisitor<ColumnResolverContext, void> {
         Column column;
 
         if (expression is Reference) {
-          var fixedName = resultColumn.as;
+          var fixedName = resultColumn.as?.name;
           if (!state.referencesUseNameOfReferencedColumn) {
             fixedName = _nameOfResultColumn(resultColumn);
           }
@@ -561,7 +562,7 @@ class ColumnResolver extends RecursiveVisitor<ColumnResolverContext, void> {
   }
 
   String? _nameOfResultColumn(ExpressionResultColumn c) {
-    if (c.as != null) return c.as;
+    if (c.as case final alias?) return alias.name;
 
     if (c.expression is Reference) {
       return (c.expression as Reference).columnName;
@@ -596,7 +597,7 @@ class ColumnResolver extends RecursiveVisitor<ColumnResolverContext, void> {
 
     if (resolvedInSchema != null) {
       return r.resolved = createdName != null
-          ? TableAlias(resolvedInSchema, createdName)
+          ? TableAlias(resolvedInSchema, createdName.name)
           : resolvedInSchema;
     } else {
       Iterable<String>? available;

sqlparser/lib/src/ast/common/queryables.dart

@@ -28,20 +28,22 @@ class TableReference extends TableOrSubquery
   Token? tableNameToken;
 
   @override
-  String? as;
+  AliasClause? as;
 
   TableReference(this.tableName, {this.as, this.schemaName});
 
   @override
-  Iterable<AstNode> get childNodes => const [];
+  Iterable<AstNode> get childNodes => [if (as case final alias?) alias];
 
   @override
   R accept<A, R>(AstVisitor<A, R> visitor, A arg) {
     return visitor.visitTableReference(this, arg);
   }
 
   @override
-  void transformChildren<A>(Transformer<A> transformer, A arg) {}
+  void transformChildren<A>(Transformer<A> transformer, A arg) {
+    as = transformer.transformNullableChild(as, this, arg);
+  }
 
   @override
   ResultSet? get resultSet {
@@ -56,7 +58,7 @@ class TableReference extends TableOrSubquery
 /// different from nested select expressions, which can only return one value.
 class SelectStatementAsSource extends TableOrSubquery implements Renamable {
   @override
-  String? as;
+  AliasClause? as;
   BaseSelectStatement statement;
 
   SelectStatementAsSource({required this.statement, this.as});
@@ -67,11 +69,13 @@ class SelectStatementAsSource extends TableOrSubquery implements Renamable {
   }
 
   @override
-  Iterable<AstNode> get childNodes => [statement];
+  Iterable<AstNode> get childNodes =>
+      [statement, if (as case final alias?) alias];
 
   @override
   void transformChildren<A>(Transformer<A> transformer, A arg) {
     statement = transformer.transformChild(statement, this, arg);
+    as = transformer.transformNullableChild(as, this, arg);
   }
 }
 
@@ -212,7 +216,7 @@ class TableValuedFunction extends Queryable
   Token? nameToken;
 
   @override
-  String? as;
+  AliasClause? as;
 
   @override
   FunctionParameters parameters;
@@ -228,11 +232,13 @@ class TableValuedFunction extends Queryable
   }
 
   @override
-  Iterable<AstNode> get childNodes => [parameters];
+  Iterable<AstNode> get childNodes =>
+      [parameters, if (as case final alias?) alias];
 
   @override
   void transformChildren<A>(Transformer<A> transformer, A arg) {
     parameters = transformer.transformChild(parameters, this, arg);
+    as = transformer.transformNullableChild(as, this, arg);
   }
 
   @override

sqlparser/lib/src/ast/common/renamable.dart

@@ -1,5 +1,29 @@
 part of '../ast.dart';
 
 abstract class Renamable {
-  String? get as;
+  AliasClause? get as;
+}
+
+/// An alias clause (e.g. `AS foo`) in SQL.
+final class AliasClause extends AstNode {
+  /// The `AS` token of this clause.
+  Token? as;
+
+  /// The name this entity has been renamed to.
+  String name;
+
+  IdentifierToken? nameToken;
+
+  AliasClause(this.name);
+
+  @override
+  R accept<A, R>(AstVisitor<A, R> visitor, A arg) {
+    return visitor.visitAliasClause(this, arg);
+  }
+
+  @override
+  Iterable<AstNode> get childNodes => const Iterable.empty();
+
+  @override
+  void transformChildren<A>(Transformer<A> transformer, A arg) {}
 }

sqlparser/lib/src/ast/drift/nested_query_column.dart

@@ -1,4 +1,4 @@
-import '../ast.dart' show ResultColumn, Renamable, SelectStatement;
+import '../ast.dart' show ResultColumn, Renamable, SelectStatement, AliasClause;
 import '../node.dart';
 import '../visitor.dart';
 import 'drift_file.dart';
@@ -20,18 +20,19 @@ class _NestedColumnNameMetadata {
 class NestedQueryColumn extends ResultColumn
     implements DriftSpecificNode, Renamable {
   @override
-  final String? as;
+  AliasClause? as;
 
   SelectStatement select;
 
   NestedQueryColumn({required this.select, this.as});
 
   @override
-  Iterable<AstNode> get childNodes => [select];
+  Iterable<AstNode> get childNodes => [select, if (as case final alias?) alias];
 
   @override
   void transformChildren<A>(Transformer<A> transformer, A arg) {
     select = transformer.transformChild(select, this, arg);
+    as = transformer.transformNullableChild(as, this, arg);
   }
 
   @override

sqlparser/lib/src/ast/drift/nested_star_result_column.dart

@@ -1,5 +1,6 @@
 import '../../analysis/analysis.dart';
-import '../ast.dart' show StarResultColumn, ResultColumn, Renamable;
+import '../ast.dart'
+    show StarResultColumn, ResultColumn, Renamable, AliasClause;
 import '../node.dart';
 import '../visitor.dart';
 import 'drift_file.dart';
@@ -15,15 +16,19 @@ class NestedStarResultColumn extends ResultColumn
   ResultSet? resultSet;
 
   @override
-  final String? as;
+  AliasClause? as;
 
   NestedStarResultColumn({required this.tableName, this.as});
 
   @override
-  Iterable<AstNode> get childNodes => const [];
+  Iterable<AstNode> get childNodes => [
+        if (as case final alias?) alias,
+      ];
 
   @override
-  void transformChildren<A>(Transformer<A> transformer, A arg) {}
+  void transformChildren<A>(Transformer<A> transformer, A arg) {
+    as = transformer.transformNullableChild(as, this, arg);
+  }
 
   @override
   R accept<A, R>(AstVisitor<A, R> visitor, A arg) {