diff --git a/chapi-domain/src/main/kotlin/chapi/domain/expr/Expression.kt b/chapi-domain/src/main/kotlin/chapi/domain/expr/Expression.kt
index a65303d0..7d82e899 100644
--- a/chapi-domain/src/main/kotlin/chapi/domain/expr/Expression.kt
+++ b/chapi-domain/src/main/kotlin/chapi/domain/expr/Expression.kt
@@ -15,6 +15,10 @@ sealed class Expression {
         override fun toString(): String = "$lhs $op $rhs"
     }
 
+    class AssignOp(val lhs: ExpressionNode, val op: AssignOpKind, val rhs: ExpressionNode) : ExpressionNode {
+        override fun toString(): String = "$lhs $op $rhs"
+    }
+
     class IntValue(val value: Int) : ExpressionNode {
         override fun toString() = value.toString()
     }
@@ -69,6 +73,53 @@ sealed class Expression {
     }
 }
 
+sealed class AssignOpKind {
+    object Assign : AssignOpKind() {
+        override fun toString() = "="
+    }
+
+    object PlusAssign : AssignOpKind() {
+        override fun toString() = "+="
+    }
+
+    object MinusAssign : AssignOpKind() {
+        override fun toString() = "-="
+    }
+
+    object MultiplyAssign : AssignOpKind() {
+        override fun toString() = "*="
+    }
+
+    object DivideAssign : AssignOpKind() {
+        override fun toString() = "/="
+    }
+
+    object ModuloAssign : AssignOpKind() {
+        override fun toString() = "%="
+    }
+
+    object BitwiseAndAssign : AssignOpKind() {
+        override fun toString() = "&="
+    }
+
+    object BitwiseOrAssign : AssignOpKind() {
+        override fun toString() = "|="
+    }
+
+    object BitwiseXorAssign : AssignOpKind() {
+        override fun toString() = "^="
+    }
+
+    object LeftShiftAssign : AssignOpKind() {
+        override fun toString() = "<<="
+    }
+
+    object RightShiftAssign : AssignOpKind() {
+        override fun toString() = ">>="
+    }
+
+}
+
 
 sealed class ComparisonOpKind {
     object Equal : ComparisonOpKind() {
diff --git a/chapi-domain/src/test/kotlin/chapi/domain/expr/ExpressionTest.kt b/chapi-domain/src/test/kotlin/chapi/domain/expr/ExpressionTest.kt
index 0be53910..40f79978 100644
--- a/chapi-domain/src/test/kotlin/chapi/domain/expr/ExpressionTest.kt
+++ b/chapi-domain/src/test/kotlin/chapi/domain/expr/ExpressionTest.kt
@@ -110,4 +110,29 @@ class ExpressionTest {
             ).toString(), "1 > 2"
         )
     }
+
+    @Test
+    fun shouldPresentationIdentSubWithParen() {
+        val binOp = Expression.BinOp(
+            lhs = Expression.Variable("a"),
+            op = BinOpKind.Add,
+            rhs = Expression.BinOp(
+                lhs = Expression.Variable("b"),
+                op = BinOpKind.Sub,
+                rhs = Expression.Variable("c")
+            )
+        )
+
+        assertEquals("a + (b - c)", binOp.toString())
+    }
+
+    @Test
+    fun assignment() {
+        assertEquals(Expression.AssignOp(
+                lhs = Expression.Variable("a"),
+                op = AssignOpKind.Assign,
+                rhs = Expression.IntValue(1)
+            ).toString(), "a = 1"
+        )
+    }
 }