diff --git a/dm_lib/std/core/array.dm b/dm_lib/std/core/array.dm
new file mode 100644
index 0000000..5236e08
--- /dev/null
+++ b/dm_lib/std/core/array.dm
@@ -0,0 +1,5 @@
+ns std::core
+
+decl pub int Array {
+    length: Int
+}
diff --git a/dm_lib/std/core/print.dm b/dm_lib/std/core/print.dm
new file mode 100644
index 0000000..0b5c401
--- /dev/null
+++ b/dm_lib/std/core/print.dm
@@ -0,0 +1,5 @@
+ns std::core
+
+decl pub fn print(message: Any)
+
+decl pub fn println(message: Any)
diff --git a/src/vm/mod.rs b/src/vm/mod.rs
index 902411d..c9a3e23 100644
--- a/src/vm/mod.rs
+++ b/src/vm/mod.rs
@@ -2,7 +2,8 @@ pub mod module;
 pub mod op_codes;
 pub mod platform;
 pub mod types;
-mod util;
+pub mod util;
+pub mod values;
 
 use crate::vm::module::DmFunction;
 use crate::vm::platform::init_platform_functions;
@@ -12,20 +13,11 @@ use std::collections::HashMap;
 use std::ops::Index;
 use types::DmType;
 use util::{get_32_le, get_64_le};
-use crate::vm::DmValue::{DmInt, DmLong, DmPointer, DmUnit};
+use values::DmValue;
+use values::DmValue::*;
 
 pub type PlatformFunction = fn(args: Vec<DmValue>, &mut DmVirtualMachine) -> DmValue;
 
-#[derive(Debug, Clone, Copy, PartialEq)]
-pub enum DmValue {
-    DmInt(i32),
-    DmLong(i64),
-    DmDouble(f64),
-    DmPointer(*mut DmObject),
-    DmUnit,
-    DmException(*mut DmObject)
-}
-
 enum CallFrame {
     PlatformCall(PlatformCallFrame),
     DeimosCall(DeimosCallFrame)
diff --git a/src/vm/platform/std_lib/core.rs b/src/vm/platform/std_lib/core.rs
index 4847092..fa516a6 100644
--- a/src/vm/platform/std_lib/core.rs
+++ b/src/vm/platform/std_lib/core.rs
@@ -1,8 +1,6 @@
-use crate::vm::types::DmType;
+use crate::vm::module::DmFunction;
 use crate::vm::DmValue::*;
 use crate::vm::{DmObject, DmValue, DmVirtualMachine};
-use DmType::*;
-use crate::vm::module::DmFunction;
 
 fn get_method<'a>(ptr: *mut DmObject, name: String) -> Option<&'a DmFunction> {
     unsafe {
@@ -10,9 +8,9 @@ fn get_method<'a>(ptr: *mut DmObject, name: String) -> Option<&'a DmFunction> {
     }
 }
 
-fn get_rust_string_from_dm_object(ptr: *mut DmObject) -> String {
+fn get_rust_string_from_dm_object(ptr: &*mut DmObject) -> String {
     unsafe {
-        let dm_object = Box::from_raw(ptr);
+        let dm_object = Box::from_raw(*ptr);
         format!("{}@{:?}", dm_object.object_type.name, dm_object.data)
     }
 }
@@ -26,20 +24,26 @@ fn get_rust_string_from_dm_string(ptr: *mut DmObject) -> String {
 
 pub fn dm_print(args: Vec<DmValue>, vm: &mut DmVirtualMachine) -> DmValue {
     if args.len() != 1 {
-        return DmException(todo!("make an Exception object."))
+        return DmUnit // TODO: make exception
     }
-    match args[0] {
+    match &args[0] {
+        DmByte(b) => {
+            print!("{}", *b);
+        }
         DmInt(i) => {
-            print!("{}", i);
+            print!("{}", *i);
         }
         DmLong(l) => {
-            print!("{}", l);
+            print!("{}", *l);
         }
         DmDouble(d) => {
-            print!("{}", d);
+            print!("{}", *d);
+        }
+        DmBoolean(b) => {
+            print!("{}", *b);
         }
         DmPointer(ptr) => {
-            if let Some(to_string) = get_method(ptr, String::from("to_string")) {
+            if let Some(to_string) = get_method(*ptr, String::from("to_string")) {
                 let call_result = vm.call(&to_string, vec![args[0]]);
                 match call_result {
                     DmPointer(dm_string_ptr) => {
@@ -54,12 +58,19 @@ pub fn dm_print(args: Vec<DmValue>, vm: &mut DmVirtualMachine) -> DmValue {
                 print!("{}", get_rust_string_from_dm_object(ptr));
             }
         },
+        DmByteArray(bs) => {
+
+        }
+        DmIntArray(is) => {
+
+        }
+        DmLongArray(ls) => {}
+        DmDoubleArray(ds) => {}
+        DmBooleanArray(bs) => {}
+        DmPointerArray(ptrs) => {}
         DmUnit => {
             print!("Unit")
         },
-        DmException(e) => {
-            print!("Exception")
-        }
     }
     DmUnit
 }
diff --git a/src/vm/types.rs b/src/vm/types.rs
index ecd8fc7..36ebf99 100644
--- a/src/vm/types.rs
+++ b/src/vm/types.rs
@@ -3,7 +3,12 @@ pub enum DmType {
     Int,
     Long,
     Double,
+    Boolean,
     Pointer,
+    IntArray,
+    LongArray,
+    DoubleArray,
+    BooleanArray,
+    PointerArray,
     Unit,
-    Exception
 }
diff --git a/src/vm/values.rs b/src/vm/values.rs
new file mode 100644
index 0000000..2d92c31
--- /dev/null
+++ b/src/vm/values.rs
@@ -0,0 +1,18 @@
+use crate::vm::DmObject;
+
+#[derive(Debug, Clone, PartialEq)]
+pub enum DmValue {
+    DmByte(u8),
+    DmInt(i32),
+    DmLong(i64),
+    DmDouble(f64),
+    DmBoolean(bool),
+    DmPointer(*mut DmObject),
+    DmByteArray(Vec<u8>),
+    DmIntArray(Vec<i32>),
+    DmLongArray(Vec<i64>),
+    DmDoubleArray(Vec<f64>),
+    DmBooleanArray(Vec<bool>),
+    DmPointerArray(Vec<*mut DmObject>),
+    DmUnit,
+}
\ No newline at end of file