diff --git a/Cargo.toml b/Cargo.toml
index 4f35267..26adae4 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "php_codegen"
-version = "0.1.0"
+version = "0.2.0"
 edition = "2021"
 description = "Generate PHP code from Rust using a fluent API 🐘 🦀"
 readme = "README.md"
@@ -15,3 +15,6 @@ keywords = ["php", "codegen", "code-generation", "php-rust-tools"]
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
+
+[dev-dependencies]
+pretty_assertions = "1.4.0"
diff --git a/src/body.rs b/src/body.rs
index ad2e288..9f4a78e 100644
--- a/src/body.rs
+++ b/src/body.rs
@@ -60,11 +60,7 @@ impl Generator for Body {
                 if self.semicolon_for_empty {
                     code.push(';');
                 } else {
-                    code.push_str(" {");
-                    code.push('\n');
-                    code.push_str(&indentation.indent("// empty body", level + 1));
-                    code.push('\n');
-                    code.push_str(&indentation.indent("}", level));
+                    code.push_str(" {}");
                 }
 
                 code.push('\n');
@@ -87,7 +83,7 @@ impl<T: ToString> From<Vec<T>> for Body {
                 let body = body.clone();
 
                 body.iter()
-                    .map(|line| indentation.indent(&line.to_string(), level))
+                    .map(|line| indentation.indent(line.to_string(), level))
                     .collect::<Vec<String>>()
                     .join("\n")
             })),
diff --git a/src/constant.rs b/src/constant.rs
index 73ebc5e..655aafa 100644
--- a/src/constant.rs
+++ b/src/constant.rs
@@ -1,5 +1,6 @@
 use crate::attribute::AttributeGroup;
 use crate::comment::Document;
+use crate::data_type::DataType;
 use crate::literal::Value;
 use crate::modifiers::Modifier;
 use crate::modifiers::VisibilityModifier;
@@ -85,6 +86,7 @@ pub struct ClassConstant {
     pub attributes: Vec<AttributeGroup>,
     pub visibility: Option<VisibilityModifier>,
     pub modifiers: Vec<Modifier>,
+    pub data_type: Option<DataType>,
     pub name: String,
     pub value: Value,
 }
@@ -96,6 +98,7 @@ impl ClassConstant {
             attributes: vec![],
             visibility: None,
             modifiers: vec![],
+            data_type: None,
             name: name.to_string(),
             value: Value::Null,
         }
@@ -143,6 +146,12 @@ impl ClassConstant {
         self
     }
 
+    pub fn typed<T: Into<DataType>>(mut self, data_type: T) -> Self {
+        self.data_type = Some(data_type.into());
+
+        self
+    }
+
     pub fn valued<T: Into<Value>>(mut self, value: T) -> Self {
         self.value = value.into();
 
@@ -172,11 +181,20 @@ impl Generator for ClassConstant {
             code.push_str(&format!("{} ", modifier.generate(indentation, level)));
         }
 
-        code.push_str(&format!(
-            "const {} = {};\n",
-            self.name,
-            self.value.generate(indentation, level)
-        ));
+        if let Some(data_type) = &self.data_type {
+            code.push_str(&format!(
+                "const {} {} = {};\n",
+                data_type.generate(indentation, level),
+                self.name,
+                self.value.generate(indentation, level)
+            ));
+        } else {
+            code.push_str(&format!(
+                "const {} = {};\n",
+                self.name,
+                self.value.generate(indentation, level)
+            ));
+        }
 
         code
     }
@@ -205,6 +223,7 @@ impl<T: ToString, Tv: Into<Value>> From<(T, Tv)> for ClassConstant {
             attributes: vec![],
             visibility: None,
             modifiers: vec![],
+            data_type: None,
             name: name.to_string(),
             value: value.into(),
         }
diff --git a/tests/complete.php b/tests/complete.php
index 509fed6..8f92caa 100644
--- a/tests/complete.php
+++ b/tests/complete.php
@@ -49,9 +49,7 @@ function hello(
     return 'Hello ' . $firstname . ' ' . $lastname . '!';
 }
 
-function nothing(): void {
-    // empty body
-}
+function nothing(): void {}
 
 function format(
     string $template,
@@ -91,6 +89,8 @@ abstract class Example extends Foo\Bar\Baz implements Foo\Bar\BazInterface
 
     public const D = false;
 
+    public const bool E = false;
+
     private string $foo;
 
     protected string $bar;
diff --git a/tests/complete.rs b/tests/complete.rs
index 9f88ee4..47a5df6 100644
--- a/tests/complete.rs
+++ b/tests/complete.rs
@@ -1,3 +1,5 @@
+use pretty_assertions::assert_eq;
+
 use php_codegen::attribute::AttributeGroup;
 use php_codegen::class::Class;
 use php_codegen::comment::Document;
@@ -129,6 +131,12 @@ fn test_code_generation() {
                 .constant(ClassConstant::new("B").valued(()).protected())
                 .constant(ClassConstant::new("C").valued(1).private())
                 .constant(ClassConstant::new("D").valued(false).public())
+                .constant(
+                    ClassConstant::new("E")
+                        .typed(DataType::Boolean)
+                        .valued(false)
+                        .public(),
+                )
                 .property(Property::new("foo").typed(DataType::String).private())
                 .property(Property::new("bar").typed(DataType::String).protected())
                 .property(