added Dibi\Expression [Closes #264]

src/Dibi/Expression.php

@@ -0,0 +1,34 @@
+<?php
+
+/**
+ * This file is part of the "dibi" - smart database abstraction layer.
+ * Copyright (c) 2005 David Grudl (https://davidgrudl.com)
+ */
+
+declare(strict_types=1);
+
+namespace Dibi;
+
+
+/**
+ * SQL expression.
+ */
+class Expression
+{
+	use Strict;
+
+	/** @var array */
+	private $values;
+
+
+	public function __construct(...$values)
+	{
+		$this->values = $values;
+	}
+
+
+	public function getValues(): array
+	{
+		return $this->values;
+	}
+}

src/Dibi/Translator.php

@@ -450,6 +450,9 @@ public function formatValue($value, ?string $modifier): string
 		} elseif ($value instanceof Literal) {
 			return (string) $value;
 
+		} elseif ($value instanceof Expression) {
+			return $this->connection->translate(...$value->getValues());
+
 		} else {
 			$type = is_object($value) ? get_class($value) : gettype($value);
 			return $this->errors[] = "**Unexpected $type**";

tests/dibi/Translator.phpt

@@ -478,7 +478,7 @@ Assert::same(
 		'title' => ['SHA1(%s)', 'Test product'],
 	], [
 		'product_id' => 1,
-		'title' => ['SHA1(%s)', 'Test product'],
+		'title' => new Dibi\Expression('SHA1(%s)', 'Test product'),
 	])
 );
 
@@ -490,6 +490,22 @@ Assert::same(
 	])
 );
 
+Assert::same(
+	reformat('UPDATE [products] [product_id]=1, [title]=SHA1(\'Test product\')'),
+	$conn->translate('UPDATE [products]', [
+		'product_id' => 1,
+		'title' => new Dibi\Expression('SHA1(%s)', 'Test product'),
+	])
+);
+
+Assert::same(
+	reformat('SELECT * FROM [products] WHERE [product_id]=1, [title]=SHA1(\'Test product\')'),
+	$conn->translate('SELECT * FROM [products] WHERE', [
+		'product_id' => 1,
+		'title' => new Dibi\Expression('SHA1(%s)', 'Test product'),
+	])
+);
+
 
 $e = Assert::exception(function () use ($conn) {
 	$array6 = [