diff --git a/lib/parser/call_site.rb b/lib/parser/call_site.rb
index b1c3f42..6ba7827 100644
--- a/lib/parser/call_site.rb
+++ b/lib/parser/call_site.rb
@@ -2,9 +2,12 @@ module Parser
   module CallSite
     include Parslet
 
-    rule(:field_access) { name.as(:receiver) >> str(".") >> name.as(:field) }
+    rule(:r_value) { operator_value | call_site | field_access | basic_type }
 
-    rule(:r_value) { call_site | field_access | basic_type }
+    rule(:assign) { str('=') >> space?}
+    rule(:assignment){ (field_access|name).as(:l_value) >> assign.as(:assign) >> r_value.as(:r_value) }
+
+    rule(:field_def) { type >> name >> (assign >> r_value.as(:value) ).maybe}
 
     rule(:argument_list) {
       left_parenthesis >>
diff --git a/test/cases/assignment/assignment_instance.tst b/test/cases/assignment/assignment_instance.tst
index 395cd9f..6836f89 100644
--- a/test/cases/assignment/assignment_instance.tst
+++ b/test/cases/assignment/assignment_instance.tst
@@ -1,6 +1,9 @@
-a = 5
+self.a = 5
 -- -- --
-s(:expressions, 
-  s(:assign, 
-    s(:name,  :a), 
-    s(:int,  5)))
+s(:assignment,
+  s(:field_access,
+    s(:receiver,
+      s(:name, :self)),
+    s(:field,
+      s(:name, :a))),
+  s(:int, 5))
diff --git a/test/cases/assignment/name.tst b/test/cases/assignment/name.tst
new file mode 100644
index 0000000..d82f603
--- /dev/null
+++ b/test/cases/assignment/name.tst
@@ -0,0 +1,5 @@
+name = 10
+-- -- --
+s(:assignment,
+  s(:name, :name),
+  s(:int, 10))
diff --git a/test/cases/call_site/call_puts_two.tst b/test/cases/call_site/call_puts_two.tst
index afdf70e..64c408b 100644
--- a/test/cases/call_site/call_puts_two.tst
+++ b/test/cases/call_site/call_puts_two.tst
@@ -1,8 +1,7 @@
 puts(3  , a )
 -- -- --
-s(:expressions, 
-  s(:call, 
-    s(:name,  :puts), 
-    s(:arguments, 
-      s(:int,  3), 
-      s(:name,  :a))))
+s(:call,
+  s(:name, :puts),
+  s(:arguments,
+    s(:int, 3),
+    s(:name, :a)))
diff --git a/test/cases/call_site/call_site_multi.tst b/test/cases/call_site/call_site_multi.tst
index f85986f..55c9c7d 100644
--- a/test/cases/call_site/call_site_multi.tst
+++ b/test/cases/call_site/call_site_multi.tst
@@ -1,8 +1,7 @@
 baz(42, foo)
 -- -- --
-s(:expressions, 
-  s(:call, 
-    s(:name,  :baz), 
-    s(:arguments, 
-      s(:int,  42), 
-      s(:name,  :foo))))
+s(:call,
+  s(:name, :baz),
+  s(:arguments,
+    s(:int, 42),
+    s(:name, :foo)))
diff --git a/test/cases/call_site/call_site_string.tst b/test/cases/call_site/call_site_string.tst
index de1d217..fac14d5 100644
--- a/test/cases/call_site/call_site_string.tst
+++ b/test/cases/call_site/call_site_string.tst
@@ -1,7 +1,6 @@
 puts( "hello")
 -- -- --
-s(:expressions, 
-  s(:call, 
-    s(:name,  :puts), 
-    s(:arguments, 
-      s(:string,  "hello"))))
+s(:call,
+  s(:name, :puts),
+  s(:arguments,
+    s(:string, "hello")))
diff --git a/test/cases/call_site/int_receiver.tst b/test/cases/call_site/int_receiver.tst
index 93ddf0a..ee4f956 100644
--- a/test/cases/call_site/int_receiver.tst
+++ b/test/cases/call_site/int_receiver.tst
@@ -1,8 +1,7 @@
 42.put()
 -- -- --
-s(:expressions, 
-  s(:call, 
-    s(:name,  :put), 
-    s(:arguments), 
-    s(:receiver, 
-      s(:int,  42))))
+s(:call,
+  s(:name, :put),
+  s(:arguments),
+  s(:receiver,
+    s(:int, 42)))
diff --git a/test/cases/call_site/puts_call.tst b/test/cases/call_site/puts_call.tst
index 2b87134..a3d6aa3 100644
--- a/test/cases/call_site/puts_call.tst
+++ b/test/cases/call_site/puts_call.tst
@@ -1,7 +1,6 @@
 puts( 5)
 -- -- --
-s(:expressions, 
-  s(:call, 
-    s(:name,  :puts), 
-    s(:arguments, 
-      s(:int,  5))))
+s(:call,
+  s(:name, :puts),
+  s(:arguments,
+    s(:int, 5)))
diff --git a/test/cases/call_site/single_argument.tst b/test/cases/call_site/single_argument.tst
index 1b9a6a0..9de72ea 100644
--- a/test/cases/call_site/single_argument.tst
+++ b/test/cases/call_site/single_argument.tst
@@ -1,7 +1,6 @@
 foo(42)
 -- -- --
-s(:expressions, 
-  s(:call, 
-    s(:name,  :foo), 
-    s(:arguments, 
-      s(:int,  42))))
+s(:call,
+  s(:name, :foo),
+  s(:arguments,
+    s(:int, 42)))
diff --git a/test/cases/call_site/single_class.tst b/test/cases/call_site/single_class.tst
index 71e0968..9e04134 100644
--- a/test/cases/call_site/single_class.tst
+++ b/test/cases/call_site/single_class.tst
@@ -1,9 +1,8 @@
 Object.foo(42)
 -- -- --
-s(:expressions, 
-  s(:call, 
-    s(:name,  :foo), 
-    s(:arguments, 
-      s(:int,  42)), 
-    s(:receiver, 
-      s(:module,  "Object"))))
+s(:call,
+  s(:name, :foo),
+  s(:arguments,
+    s(:int, 42)),
+  s(:receiver,
+    s(:class_name, :Object)))
diff --git a/test/cases/call_site/single_name.tst b/test/cases/call_site/single_name.tst
index ec24552..a2dee1e 100644
--- a/test/cases/call_site/single_name.tst
+++ b/test/cases/call_site/single_name.tst
@@ -1,9 +1,8 @@
 my_my.foo(42)
 -- -- --
-s(:expressions, 
-  s(:call, 
-    s(:name,  :foo), 
-    s(:arguments, 
-      s(:int,  42)), 
-    s(:receiver, 
-      s(:name,  :my_my))))
+s(:call,
+  s(:name, :foo),
+  s(:arguments,
+    s(:int, 42)),
+  s(:receiver,
+    s(:name, :my_my)))
diff --git a/test/cases/call_site/single_self.tst b/test/cases/call_site/single_self.tst
index 1161e31..6006843 100644
--- a/test/cases/call_site/single_self.tst
+++ b/test/cases/call_site/single_self.tst
@@ -1,9 +1,8 @@
 self.foo(42)
 -- -- --
-s(:expressions, 
-  s(:call, 
-    s(:name,  :foo), 
-    s(:arguments, 
-      s(:int,  42)), 
-    s(:receiver, 
-      s(:name,  :self))))
+s(:call,
+  s(:name, :foo),
+  s(:arguments,
+    s(:int, 42)),
+  s(:receiver,
+    s(:name, :self)))
diff --git a/test/cases/call_site/string_receiver.tst b/test/cases/call_site/string_receiver.tst
index e3bcc23..0b6b860 100644
--- a/test/cases/call_site/string_receiver.tst
+++ b/test/cases/call_site/string_receiver.tst
@@ -1,8 +1,7 @@
 "hello".puts()
 -- -- --
-s(:expressions, 
-  s(:call, 
-    s(:name,  :puts), 
-    s(:arguments), 
-    s(:receiver, 
-      s(:string,  "hello"))))
+s(:call,
+  s(:name, :puts),
+  s(:arguments),
+  s(:receiver,
+    s(:string, "hello")))