Generate code to match default values for CREATE TABLE

moor/lib/src/runtime/expressions/user_api.dart

@@ -1,4 +1,5 @@
 export 'bools.dart' show and, or, not;
+export 'custom.dart';
 export 'datetimes.dart';
 export 'in.dart';
 export 'null_check.dart';

moor/test/data/tables/custom_tables.g.dart

@@ -201,7 +201,9 @@ class WithDefaults extends Table with TableInfo<WithDefaults, WithDefault> {
   GeneratedTextColumn get a => _a ??= _constructA();
   GeneratedTextColumn _constructA() {
     return GeneratedTextColumn('a', $tableName, true,
-        $customConstraints: 'DEFAULT \'something\'');
+        $customConstraints: 'DEFAULT \'something\'',
+        defaultValue:
+            const CustomExpression<String, StringType>('\'something\''));
   }
 
   final VerificationMeta _bMeta = const VerificationMeta('b');

moor_generator/lib/src/model/specified_column.dart

@@ -1,4 +1,3 @@
-import 'package:analyzer/dart/ast/ast.dart';
 import 'package:built_value/built_value.dart';
 import 'package:moor_generator/src/model/used_type_converter.dart';
 
@@ -61,6 +60,15 @@ const Map<ColumnType, String> createVariable = {
   ColumnType.real: 'Variable.withReal',
 };
 
+const Map<ColumnType, String> sqlTypes = {
+  ColumnType.boolean: 'BoolType',
+  ColumnType.text: 'StringType',
+  ColumnType.integer: 'IntType',
+  ColumnType.datetime: 'DateTimeType',
+  ColumnType.blob: 'BlobType',
+  ColumnType.real: 'RealType',
+};
+
 /// A column, as specified by a getter in a table.
 class SpecifiedColumn {
   /// The getter name of this column in the table class. It will also be used
@@ -95,10 +103,9 @@ class SpecifiedColumn {
   /// default ones.
   final String customConstraints;
 
-  /// If a default expression has been provided as the argument of
-  /// ColumnBuilder.withDefault, contains the Dart code that references that
-  /// expression.
-  final Expression defaultArgument;
+  /// Dart code that generates the default expression for this column, or null
+  /// if there is no default expression.
+  final String defaultArgument;
 
   /// The [UsedTypeConverter], if one has been set on this column.
   final UsedTypeConverter typeConverter;
@@ -142,14 +149,7 @@ class SpecifiedColumn {
 
   /// The class inside the moor library that represents the same sql type as
   /// this column.
-  String get sqlTypeName => const {
-        ColumnType.boolean: 'BoolType',
-        ColumnType.text: 'StringType',
-        ColumnType.integer: 'IntType',
-        ColumnType.datetime: 'DateTimeType',
-        ColumnType.blob: 'BlobType',
-        ColumnType.real: 'RealType',
-      }[type];
+  String get sqlTypeName => sqlTypes[type];
 
   const SpecifiedColumn({
     this.type,

moor_generator/lib/src/parser/column_parser.dart

@@ -199,7 +199,7 @@ class ColumnParser extends ParserBase {
         customConstraints: foundCustomConstraint,
         nullable: nullable,
         features: foundFeatures,
-        defaultArgument: foundDefaultExpression,
+        defaultArgument: foundDefaultExpression?.toSource(),
         typeConverter: converter);
   }
 

moor_generator/lib/src/parser/moor/parsed_moor_file.dart

@@ -2,6 +2,7 @@ import 'package:moor_generator/src/model/specified_column.dart';
 import 'package:moor_generator/src/model/specified_table.dart';
 import 'package:moor_generator/src/parser/sql/type_mapping.dart';
 import 'package:moor_generator/src/utils/names.dart';
+import 'package:moor_generator/src/utils/string_escaper.dart';
 import 'package:recase/recase.dart';
 import 'package:sqlparser/sqlparser.dart';
 
@@ -45,6 +46,8 @@ class CreateTable {
       final sqlName = column.name;
       final dartName = ReCase(sqlName).camelCase;
       final constraintWriter = StringBuffer();
+      final moorType = mapper.resolvedToMoor(column.type);
+      String defaultValue;
 
       for (var constraint in column.constraints) {
         if (constraint is PrimaryKeyColumn) {
@@ -53,6 +56,13 @@ class CreateTable {
             features.add(AutoIncrement());
           }
         }
+        if (constraint is Default) {
+          final dartType = dartTypeNames[moorType];
+          final sqlType = sqlTypes[moorType];
+          final expressionName = 'const CustomExpression<$dartType, $sqlType>';
+          final sqlDefault = constraint.expression.span.text;
+          defaultValue = '$expressionName(${asDartLiteral(sqlDefault)})';
+        }
 
         if (constraintWriter.isNotEmpty) {
           constraintWriter.write(' ');
@@ -61,13 +71,14 @@ class CreateTable {
       }
 
       final parsed = SpecifiedColumn(
-        type: mapper.resolvedToMoor(column.type),
+        type: moorType,
         nullable: column.type.nullable,
         dartGetterName: dartName,
         name: ColumnName.implicitly(sqlName),
         declaredAsPrimaryKey: isPrimaryKey,
         features: features,
         customConstraints: constraintWriter.toString(),
+        defaultArgument: defaultValue,
       );
 
       foundColumns[column.name] = parsed;

moor_generator/lib/src/writer/table_writer.dart

@@ -149,7 +149,7 @@ class TableWriter {
     }
 
     if (column.defaultArgument != null) {
-      additionalParams['defaultValue'] = column.defaultArgument.toSource();
+      additionalParams['defaultValue'] = column.defaultArgument;
     }
 
     expressionBuffer