Rename to computed() & $expression, throw exceptions when not supported

src/Illuminate/Database/Schema/Blueprint.php

@@ -823,15 +823,15 @@ public function unsignedDecimal($column, $total = 8, $places = 2)
     }
 
     /**
-     * Create a new generated virtual column on the table.
+     * Create a new generated computed column on the table.
      *
      * @param  string  $column
-     * @param  string  $formula
+     * @param  string  $expression
      * @return \Illuminate\Database\Schema\ColumnDefinition
      */
-    public function virtual($column, $formula)
+    public function computed($column, $expression)
     {
-        return $this->addColumn('virtual', $column, compact('formula'));
+        return $this->addColumn('computed', $column, compact('expression'));
     }
 
     /**

src/Illuminate/Database/Schema/ColumnDefinition.php

@@ -24,7 +24,7 @@
  * @method ColumnDefinition unsigned() Set the INTEGER column as UNSIGNED (MySQL)
  * @method ColumnDefinition useCurrent() Set the TIMESTAMP column to use CURRENT_TIMESTAMP as default value
  * @method ColumnDefinition virtualAs(string $expression) Create a virtual generated column (MySQL)
- * @method ColumnDefinition persisted() Mark the virtual generated column as persistent (SQL Server)
+ * @method ColumnDefinition persisted() Mark the computed generated column as persistent (SQL Server)
  */
 class ColumnDefinition extends Fluent
 {

src/Illuminate/Database/Schema/Grammars/Grammar.php

@@ -2,6 +2,7 @@
 
 namespace Illuminate\Database\Schema\Grammars;
 
+use RuntimeException;
 use Illuminate\Support\Fluent;
 use Doctrine\DBAL\Schema\TableDiff;
 use Illuminate\Database\Connection;
@@ -190,6 +191,18 @@ public function prefixArray($prefix, array $values)
         }, $values);
     }
 
+    /**
+     * Create the column definition for a generated computed column type.
+     *
+     * @param  \Illuminate\Support\Fluent  $column
+     *
+     * @throws \RuntimeException
+     */
+    protected function typeComputed(Fluent $column)
+    {
+        throw new RuntimeException('The database driver in use does not support the computed type.');
+    }
+
     /**
      * Wrap a table in keyword identifiers.
      *

src/Illuminate/Database/Schema/Grammars/MySqlGrammar.php

@@ -2,6 +2,7 @@
 
 namespace Illuminate\Database\Schema\Grammars;
 
+use RuntimeException;
 use Illuminate\Support\Fluent;
 use Illuminate\Database\Connection;
 use Illuminate\Database\Schema\Blueprint;
@@ -833,6 +834,18 @@ public function typeMultiPolygon(Fluent $column)
         return 'multipolygon';
     }
 
+    /**
+     * Create the column definition for a generated computed column type.
+     *
+     * @param  \Illuminate\Support\Fluent  $column
+     *
+     * @throws \RuntimeException
+     */
+    protected function typeComputed(Fluent $column)
+    {
+        throw new RuntimeException('The database driver in use requires a type, see virtualAs/storedAs modifiers.');
+    }
+
     /**
      * Get the SQL for a generated virtual column modifier.
      *

src/Illuminate/Database/Schema/Grammars/SqlServerGrammar.php

@@ -734,14 +734,14 @@ public function typeMultiPolygon(Fluent $column)
     }
 
     /**
-     * Create the column definition for a generated virtual column type.
+     * Create the column definition for a generated computed column type.
      *
      * @param  \Illuminate\Support\Fluent  $column
      * @return string|null
      */
-    protected function typeVirtual(Fluent $column)
+    protected function typeComputed(Fluent $column)
     {
-        return "as ({$column->formula})";
+        return "as ({$column->expression})";
     }
 
     /**
@@ -767,7 +767,7 @@ protected function modifyCollate(Blueprint $blueprint, Fluent $column)
      */
     protected function modifyNullable(Blueprint $blueprint, Fluent $column)
     {
-        if ($column->type !== 'virtual') {
+        if ($column->type !== 'computed') {
             return $column->nullable ? ' null' : ' not null';
         }
     }

tests/Database/DatabaseSqlServerSchemaGrammarTest.php

@@ -774,8 +774,8 @@ public function testAddingGeneratedColumn()
     {
         $blueprint = new Blueprint('products');
         $blueprint->integer('price');
-        $blueprint->virtual('discounted_virtual', 'price - 5');
-        $blueprint->virtual('discounted_stored', 'price - 5')->persisted();
+        $blueprint->computed('discounted_virtual', 'price - 5');
+        $blueprint->computed('discounted_stored', 'price - 5')->persisted();
         $statements = $blueprint->toSql($this->getConnection(), $this->getGrammar());
         $this->assertCount(1, $statements);
         $this->assertEquals('alter table "products" add "price" int not null, "discounted_virtual" as (price - 5), "discounted_stored" as (price - 5) persisted', $statements[0]);