diff --git a/src/AsFloat.php b/src/AsFloat.php
index a9a6b54..d0e762c 100644
--- a/src/AsFloat.php
+++ b/src/AsFloat.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace Kiboko\Component\StringExpressionLanguage;
 
@@ -18,7 +20,7 @@ public function __construct($name)
     private function compile(string $value): string
     {
         return <<<PHP
-                ((float) $value)
+                ((float) {$value})
             PHP;
     }
 
diff --git a/src/AsInteger.php b/src/AsInteger.php
index 60f5b8a..2b19457 100644
--- a/src/AsInteger.php
+++ b/src/AsInteger.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace Kiboko\Component\StringExpressionLanguage;
 
@@ -18,7 +20,7 @@ public function __construct($name)
     private function compile(string $value): string
     {
         return <<<PHP
-                ((int) $value)
+                ((int) {$value})
             PHP;
     }
 
diff --git a/src/Capitalize.php b/src/Capitalize.php
new file mode 100644
index 0000000..15795c6
--- /dev/null
+++ b/src/Capitalize.php
@@ -0,0 +1,41 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Kiboko\Component\StringExpressionLanguage;
+
+use Symfony\Component\ExpressionLanguage\ExpressionFunction;
+
+final class Capitalize extends ExpressionFunction
+{
+    public function __construct($name)
+    {
+        parent::__construct(
+            $name,
+            \Closure::fromCallable($this->compile(...))->bindTo($this),
+            \Closure::fromCallable($this->evaluate(...))->bindTo($this)
+        );
+    }
+
+    private function compile(string $input): string
+    {
+        return <<<PHP
+            (
+                !\\is_string({$input}) ?
+                null :
+                (
+                    mb_convert_case(mb_substr({$input}, 0, 1), \\MB_CASE_UPPER) . mb_substr({$input}, 1, -1)
+                )
+            )
+            PHP;
+    }
+
+    private function evaluate(array $context, string $input)
+    {
+        return !\is_string($input) ?
+            null :
+            (
+                mb_convert_case(mb_substr($input, 0, 1), \MB_CASE_UPPER).mb_substr($input, 1, -1)
+            );
+    }
+}
diff --git a/src/CapitalizeWords.php b/src/CapitalizeWords.php
new file mode 100644
index 0000000..1d226c5
--- /dev/null
+++ b/src/CapitalizeWords.php
@@ -0,0 +1,41 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Kiboko\Component\StringExpressionLanguage;
+
+use Symfony\Component\ExpressionLanguage\ExpressionFunction;
+
+final class CapitalizeWords extends ExpressionFunction
+{
+    public function __construct($name)
+    {
+        parent::__construct(
+            $name,
+            \Closure::fromCallable($this->compile(...))->bindTo($this),
+            \Closure::fromCallable($this->evaluate(...))->bindTo($this)
+        );
+    }
+
+    private function compile(string $input): string
+    {
+        return <<<PHP
+            (
+                !\\is_string({$input}) ?
+                null :
+                (
+                    mb_convert_case({$input}, \\MB_CASE_TITLE)
+                )
+            )
+            PHP;
+    }
+
+    private function evaluate(array $context, string $input)
+    {
+        return !\is_string($input) ?
+            null :
+            (
+                mb_convert_case($input, \MB_CASE_TITLE)
+            );
+    }
+}
diff --git a/src/ConvertCharCode.php b/src/ConvertCharCode.php
index 5498464..6bc4078 100644
--- a/src/ConvertCharCode.php
+++ b/src/ConvertCharCode.php
@@ -20,7 +20,7 @@ public function __construct($name)
     private function compile(string $text, string $sourceCharCode, string $destinationCharCode): string
     {
         return <<<"PHP"
-            iconv($sourceCharCode, $destinationCharCode, $text)
+            iconv({$sourceCharCode}, {$destinationCharCode}, {$text})
             PHP;
     }
 
diff --git a/src/StringExpressionLanguageProvider.php b/src/StringExpressionLanguageProvider.php
index e42da97..206f2f7 100644
--- a/src/StringExpressionLanguageProvider.php
+++ b/src/StringExpressionLanguageProvider.php
@@ -14,19 +14,20 @@ public function getFunctions(): array
         return [
             ExpressionFunction::fromPhp('sprintf', 'format'),
             ExpressionFunction::fromPhp('trim', 'trim'),
-            ExpressionFunction::fromPhp('ucfirst', 'capitalize'),
-            ExpressionFunction::fromPhp('strtolower', 'toLowerCase'),
+            new Capitalize('capitalize'),
+            new ToLowerCase('toLowerCase'),
             ExpressionFunction::fromPhp('mb_substr', 'search'),
-            ExpressionFunction::fromPhp('strtoupper', 'toUpperCase'),
+            new ToUpperCase('toUpperCase'),
             ExpressionFunction::fromPhp('number_format', 'formatNumber'),
             ExpressionFunction::fromPhp('strpos', 'indexOf'),
             ExpressionFunction::fromPhp('str_replace', 'replace'),
             ExpressionFunction::fromPhp('strip_tags', 'stripHtml'),
             ExpressionFunction::fromPhp('json_decode', 'decode'),
             ExpressionFunction::fromPhp('preg_replace', 'replaceByExpression'),
-            ExpressionFunction::fromPhp('ucwords', 'capitalizeWords'),
+            new CapitalizeWords('capitalizeWords'),
             ExpressionFunction::fromPhp('rtrim', 'removeWhitespaces'),
             ExpressionFunction::fromPhp('explode', 'splitIntoArray'),
+            new Truncate('truncate'),
             new FileName('fileName'),
             new DateTime('dateTime'),
             new FormatDate('formatDate'),
diff --git a/src/ToLowerCase.php b/src/ToLowerCase.php
new file mode 100644
index 0000000..6845bea
--- /dev/null
+++ b/src/ToLowerCase.php
@@ -0,0 +1,41 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Kiboko\Component\StringExpressionLanguage;
+
+use Symfony\Component\ExpressionLanguage\ExpressionFunction;
+
+final class ToLowerCase extends ExpressionFunction
+{
+    public function __construct($name)
+    {
+        parent::__construct(
+            $name,
+            \Closure::fromCallable($this->compile(...))->bindTo($this),
+            \Closure::fromCallable($this->evaluate(...))->bindTo($this)
+        );
+    }
+
+    private function compile(string $input): string
+    {
+        return <<<PHP
+            (
+                !\\is_string({$input}) ?
+                null :
+                (
+                    mb_convert_case({$input}, \\MB_CASE_LOWER)
+                )
+            )
+            PHP;
+    }
+
+    private function evaluate(array $context, string $input)
+    {
+        return !\is_string($input) ?
+            null :
+            (
+                mb_convert_case($input, \MB_CASE_LOWER)
+            );
+    }
+}
diff --git a/src/ToUpperCase.php b/src/ToUpperCase.php
new file mode 100644
index 0000000..8b42bef
--- /dev/null
+++ b/src/ToUpperCase.php
@@ -0,0 +1,41 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Kiboko\Component\StringExpressionLanguage;
+
+use Symfony\Component\ExpressionLanguage\ExpressionFunction;
+
+final class ToUpperCase extends ExpressionFunction
+{
+    public function __construct($name)
+    {
+        parent::__construct(
+            $name,
+            \Closure::fromCallable($this->compile(...))->bindTo($this),
+            \Closure::fromCallable($this->evaluate(...))->bindTo($this)
+        );
+    }
+
+    private function compile(string $input): string
+    {
+        return <<<PHP
+            (
+                !\\is_string({$input}) ?
+                null :
+                (
+                    mb_convert_case({$input}, \\MB_CASE_UPPER)
+                )
+            )
+            PHP;
+    }
+
+    private function evaluate(array $context, string $input)
+    {
+        return !\is_string($input) ?
+            null :
+            (
+                mb_convert_case($input, \MB_CASE_UPPER)
+            );
+    }
+}
diff --git a/src/Truncate.php b/src/Truncate.php
new file mode 100644
index 0000000..a0c53d9
--- /dev/null
+++ b/src/Truncate.php
@@ -0,0 +1,41 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Kiboko\Component\StringExpressionLanguage;
+
+use Symfony\Component\ExpressionLanguage\ExpressionFunction;
+
+final class Truncate extends ExpressionFunction
+{
+    public function __construct($name)
+    {
+        parent::__construct(
+            $name,
+            \Closure::fromCallable($this->compile(...))->bindTo($this),
+            \Closure::fromCallable($this->evaluate(...))->bindTo($this)
+        );
+    }
+
+    private function compile(string $input, string $limit): string
+    {
+        return <<<PHP
+            (
+                !\\is_string({$input}) ?
+                null :
+                (
+                    rtrim(mb_substr({$input}, 0, {$limit} - 1)) . '…'
+                )
+            )
+            PHP;
+    }
+
+    private function evaluate(array $context, string $input, int $limit)
+    {
+        return !\is_string($input) ?
+            null :
+            (
+                rtrim(mb_substr($input, 0, $limit - 1)).'…'
+            );
+    }
+}