diff --git a/packages/core/error.huia b/packages/core/error.huia
new file mode 100644
index 0000000..25a12a2
--- /dev/null
+++ b/packages/core/error.huia
@@ -0,0 +1,7 @@
+deftype Error message: String, backtrace: Array, as: ->
+
+  defstatic <Error> new message: String, backtrace: Array, as: ->
+    Error { message: message, backtrace: backtrace }
+  end
+
+end
diff --git a/packages/core/error/option.huia b/packages/core/error/option.huia
new file mode 100644
index 0000000..c50dc1c
--- /dev/null
+++ b/packages/core/error/option.huia
@@ -0,0 +1,14 @@
+defimpl Option for: Error, as: ->
+
+  def some? as: -> false end
+  def none? as: -> true end
+
+  def <Any> unwrap as: ->
+    Huia.Primitive.panic("Attempt to unwrap Error")
+  end
+
+  def <Any> expect message: String, as: ->
+    Huia.Primitive.panic(message)
+  end
+
+end
diff --git a/packages/core/error/result.huia b/packages/core/error/result.huia
new file mode 100644
index 0000000..5805177
--- /dev/null
+++ b/packages/core/error/result.huia
@@ -0,0 +1,14 @@
+defimpl Result for: Error, as: ->
+
+  def ok? as: -> false end
+  def error? as: -> true end
+
+  def <Any> ok as: ->
+    Huia.Primitive.panic("Attempt to convert error into value")
+  end
+
+  def <Any> error as: ->
+    self
+  end
+
+end
diff --git a/packages/core/float.huia b/packages/core/float.huia
index 12ff589..2247052 100644
--- a/packages/core/float.huia
+++ b/packages/core/float.huia
@@ -1,4 +1,4 @@
-deftrait Integer requires: [
+deftrait Float requires: [
     Addition,
     Division,
     Equality,
diff --git a/packages/core/native/float_64/addition.huia b/packages/core/native/float_64/addition.huia
index 015c853..113a18e 100644
--- a/packages/core/native/float_64/addition.huia
+++ b/packages/core/native/float_64/addition.huia
@@ -1,12 +1,12 @@
 defimpl Addition for: Native.Float64, as: ->
 
   def add other: Native.Integer64, as: ->
-    as_float = Huia.Primitive.i64_to_f64!(value: other)
-    Huia.Primitive.f64_addition(rhs: self, lhs: as_float)
+    as_float = Huia.Primitive.i64_to_f64!(other)
+    Huia.Primitive.f64_addition(self, as_float)
   end
 
   def add other: Native.Float64, as: ->
-    Huia.Primitive.f64_addition(rhs: self, lhs: other)
+    Huia.Primitive.f64_addition(self, other)
   end
 
   def add other: Any, as: ->
diff --git a/packages/core/native/float_64/division.huia b/packages/core/native/float_64/division.huia
index 42a1c30..02c3b3b 100644
--- a/packages/core/native/float_64/division.huia
+++ b/packages/core/native/float_64/division.huia
@@ -1,12 +1,12 @@
 defimpl Division for: Native.Float64, as: ->
 
   def divide_by other: Native.Float64, as: ->
-    Huia.Primitive.f64_division(lhs: self, rhs: other)
+    Huia.Primitive.f64_division(self, other)
   end
 
   def divide_by other: Native.Integer64, as: ->
-    as_float = Huia.Primitive.i64_to_f64!(value: other)
-    Huia.Primitive.f64_division(lhs: self, rhs: as_float)
+    as_float = Huia.Primitive.i64_to_f64!(other)
+    Huia.Primitive.f64_division(self, as_float)
   end
 
   def divide_by other: Any, as: ->
diff --git a/packages/core/native/float_64/equality.huia b/packages/core/native/float_64/equality.huia
index b488c86..e8a55fc 100644
--- a/packages/core/native/float_64/equality.huia
+++ b/packages/core/native/float_64/equality.huia
@@ -1,7 +1,7 @@
 defimpl Equality for: Native.Float64, as: ->
 
   def equals? other: Native.Float64, as: ->
-    Huia.Primitive.f64_equals(lhs: self, rhs: other)
+    Huia.Primitive.f64_equals(self, other)
   end
 
   def equals? other: Any, as: -> false
diff --git a/packages/core/native/float_64/multiplication.huia b/packages/core/native/float_64/multiplication.huia
index 991f651..490b1d9 100644
--- a/packages/core/native/float_64/multiplication.huia
+++ b/packages/core/native/float_64/multiplication.huia
@@ -1,12 +1,12 @@
 defimpl Multiplication for: Native.Float64, as: ->
 
   def multiply_by other: Native.Float64, as: ->
-    Huia.Primitive.f64_multiply_by(lhs: self, rhs: other)
+    Huia.Primitive.f64_multiply_by(self, other)
   end
 
   def multiply_by other: Native.Integer64, as: ->
-    as_float = Huia.Primitive.i64_to_f64!(value: other)
-    Huia.Primitive.f64_multiply_by(lhs: self, rhs: as_float)
+    as_float = Huia.Primitive.i64_to_f64!(other)
+    Huia.Primitive.f64_multiply_by(self, as_float)
   end
 
   def multiply_by other: Any, as: ->
diff --git a/packages/core/native/integer_64/addition.huia b/packages/core/native/integer_64/addition.huia
index bb5e957..fb317d2 100644
--- a/packages/core/native/integer_64/addition.huia
+++ b/packages/core/native/integer_64/addition.huia
@@ -1,12 +1,12 @@
 defimpl Addition for: Native.Integer64, as: ->
 
   def add other: Native.Integer64, as: ->
-    Huia.Primitive.i64_addition(lhs: self, rhs: other)
+    Huia.Primitive.i64_addition(self, other)
   end
 
   def add other: Native.Float64, as: ->
-    as_float = Huia.Primitive.i64_to_f64!(value: self)
-    Huia.Primitive.f64_addition(lhs: as_float, rhs: other)
+    as_float = Huia.Primitive.i64_to_f64!(self)
+    Huia.Primitive.f64_addition(as_float, other)
   end
 
   def add other: Any, as: ->
diff --git a/packages/core/native/integer_64/bitwise_and.huia b/packages/core/native/integer_64/bitwise_and.huia
index ed4ba6c..3183d71 100644
--- a/packages/core/native/integer_64/bitwise_and.huia
+++ b/packages/core/native/integer_64/bitwise_and.huia
@@ -1,7 +1,7 @@
 defimpl BitwiseAnd for: Native.Integer64, as: ->
 
   def bitwise_and other: Native.Integer64, as: ->
-    Huia.Primitive.i64_bitwise_and(lhs: self, rhs: other)
+    Huia.Primitive.i64_bitwise_and(self, other)
   end
 
   def bitwise_and other: Any, as: ->
diff --git a/packages/core/native/integer_64/bitwise_or.huia b/packages/core/native/integer_64/bitwise_or.huia
index 0949033..db9afcd 100644
--- a/packages/core/native/integer_64/bitwise_or.huia
+++ b/packages/core/native/integer_64/bitwise_or.huia
@@ -1,7 +1,7 @@
 defimpl BitwiseOr for: Native.Integer64, as: ->
 
   def bitwise_or other: Native.Integer64, as: ->
-    Huia.Primitive.i64_bitwise_or(lhs: self, rhs: other)
+    Huia.Primitive.i64_bitwise_or(self, other)
   end
 
   def bitwise_or other: Any, as: ->
diff --git a/packages/core/native/integer_64/bitwise_xor.huia b/packages/core/native/integer_64/bitwise_xor.huia
index 48c01e4..7da4acd 100644
--- a/packages/core/native/integer_64/bitwise_xor.huia
+++ b/packages/core/native/integer_64/bitwise_xor.huia
@@ -1,7 +1,7 @@
 defimpl BitwiseXor for: Native.Integer64, as: ->
 
   def bitwise_xor other: Native.Integer64, as: ->
-    Huia.Primitive.i64_bitwise_xor(lhs: self, rhs: other)
+    Huia.Primitive.i64_bitwise_xor(self, other)
   end
 
   def bitwise_xor other: Any, as: ->
diff --git a/packages/core/native/integer_64/division.huia b/packages/core/native/integer_64/division.huia
index 02ab050..78dacf1 100644
--- a/packages/core/native/integer_64/division.huia
+++ b/packages/core/native/integer_64/division.huia
@@ -1,12 +1,12 @@
 defimpl Division for: Native.Integer64, as: ->
 
   def divide_by other: Native.Integer64, as: ->
-    Huia.Primitive.i64_division(lhs: self, rhs: other)
+    Huia.Primitive.i64_division(self, other)
   end
 
   def divide_by other: Native.Float64, as: ->
-    as_float = Huia.Primitive.i64_to_f64!(value: self)
-    Huia.Primitive.f64_division(lhs: as_float, rhs: other)
+    as_float = Huia.Primitive.i64_to_f64!(self)
+    Huia.Primitive.f64_division(as_float, other)
   end
 
   def divide_by other: Any, as: ->
diff --git a/packages/core/native/integer_64/equality.huia b/packages/core/native/integer_64/equality.huia
index bde292b..5b0e01a 100644
--- a/packages/core/native/integer_64/equality.huia
+++ b/packages/core/native/integer_64/equality.huia
@@ -1,7 +1,7 @@
 defimpl Equality for: Native.Integer64, as: ->
 
   def equals? other: Native.Integer64, as: ->
-    Huia.Primitive.i64_equals(lhs: self, rhs: other)
+    Huia.Primitive.i64_equals(self, other)
   end
 
   def equals? other: Any, as: -> false
diff --git a/packages/core/native/integer_64/exponentiation.huia b/packages/core/native/integer_64/exponentiation.huia
index 96ececc..1512c34 100644
--- a/packages/core/native/integer_64/exponentiation.huia
+++ b/packages/core/native/integer_64/exponentiation.huia
@@ -1,12 +1,12 @@
 defimpl Exponentiation for: Native.Integer64, as: ->
 
   def exponent_of other: Native.Integer64, as: ->
-    Huia.Primitive.i64_expo(lhs: self, rhs: other)
+    Huia.Primitive.i64_expo(self, other)
   end
 
   def exponent_of other: Native.Float64, as: ->
-    as_float = Huia.Primitive.i64_to_f64!(value: self)
-    Native.Primitive.f64_expo(lhs: self, rhs: other)
+    as_float = Huia.Primitive.i64_to_f64!(self)
+    Native.Primitive.f64_expo(self, other)
   end
 
   def exponent_of other: Any, as: ->
diff --git a/packages/core/native/integer_64/logical_and.huia b/packages/core/native/integer_64/logical_and.huia
index ecc17c1..249e1d7 100644
--- a/packages/core/native/integer_64/logical_and.huia
+++ b/packages/core/native/integer_64/logical_and.huia
@@ -1,7 +1,7 @@
 defimpl LogicalAnd for: Native.Integer64, as: ->
 
   def logical_and other: Native.Integer64, as: ->
-    Huia.Primitive.i64_logical_and(lhs: self, other: other)
+    Huia.Primitive.i64_logical_and(self, other)
   end
 
   def logical_and other: Any, as: ->
diff --git a/packages/core/native/integer_64/logical_not.huia b/packages/core/native/integer_64/logical_not.huia
index bb01e58..4756ad9 100644
--- a/packages/core/native/integer_64/logical_not.huia
+++ b/packages/core/native/integer_64/logical_not.huia
@@ -1,7 +1,7 @@
 defimpl LogicalNot for: Native.Integer64, as: ->
 
   def logical_and other: Native.Integer64, as: ->
-    Huia.Primitive.i64_logical_and(lhs: self, other: other)
+    Huia.Primitive.i64_logical_and(self, other)
   end
 
   def logical_and other: Any, as: ->
diff --git a/packages/core/native/integer_64/logical_or.huia b/packages/core/native/integer_64/logical_or.huia
index bf4677e..b233849 100644
--- a/packages/core/native/integer_64/logical_or.huia
+++ b/packages/core/native/integer_64/logical_or.huia
@@ -1,7 +1,7 @@
 defimpl LogicalOr for: Native.Integer64, as: ->
 
   def logical_or other: Native.Integer64, as: ->
-    Huia.Primitive.i64_logical_or(lhs: self, rhs: other)
+    Huia.Primitive.i64_logical_or(self, other)
   end
 
   def logical_or other: Any, as: ->
diff --git a/packages/core/native/integer_64/modulus.huia b/packages/core/native/integer_64/modulus.huia
index 92d02c4..48cd5a7 100644
--- a/packages/core/native/integer_64/modulus.huia
+++ b/packages/core/native/integer_64/modulus.huia
@@ -1,7 +1,7 @@
 defimpl Modulus for: Native.Integer64, as: ->
 
   def modulo other: Native.Integer64, as: ->
-    Huia.Primitive.i64_modulo(lhs: self, rhs: other)
+    Huia.Primitive.i64_modulo(self, other)
   end
 
   def modulo other: Any, as: ->
diff --git a/packages/core/native/integer_64/multiplication.huia b/packages/core/native/integer_64/multiplication.huia
index 1f4dd19..865a824 100644
--- a/packages/core/native/integer_64/multiplication.huia
+++ b/packages/core/native/integer_64/multiplication.huia
@@ -1,12 +1,12 @@
 defimpl Multiplication for: Native.Integer64, as: ->
 
   def multiply_by other: Native.Integer64, as: ->
-    Huia.Primitive.i64_multiply_by(lhs: self, rhs: other)
+    Huia.Primitive.i64_multiply_by(self, other)
   end
 
   def multiply_by other: Native.Float64, as: ->
-    as_float = Huia.Primitive.i64_to_f64!(value: self)
-    Huia.Primitive.f64_multiply_by(lhs: as_float, rhs: other)
+    as_float = Huia.Primitive.i64_to_f64!(self)
+    Huia.Primitive.f64_multiply_by(as_float, other)
   end
 
   def multiply_by other: Any, as: ->
diff --git a/packages/core/native/integer_64/ordering.huia b/packages/core/native/integer_64/ordering.huia
index 0cf34b1..df4a478 100644
--- a/packages/core/native/integer_64/ordering.huia
+++ b/packages/core/native/integer_64/ordering.huia
@@ -1,14 +1,14 @@
 defimpl Ordering for: Native.Integer64, as: ->
 
   def <Ordering.Result> compare_with other: Native.Integer64, as: ->
-    match Huia.Primitive.i64_compare(lhs: self, rhs: other),
+    match Huia.Primitive.i64_compare(self, other),
       -1: -> Ordering.Less.new() end,
       0: -> Ordering.Equal.new() end,
       1: -> Ordering.Greater.new() end
   end
 
   def equals? other: Native.Integer64, as: ->
-    match Huia.Primitive.i64_compare(lhs: self, rhs: other),
+    match Huia.Primitive.i64_compare(self, other),
       0: -> true end,
       Any: -> false end
   end
@@ -16,14 +16,14 @@ defimpl Ordering for: Native.Integer64, as: ->
   def equals? other: Any, as: -> false
 
   def greater_than? other: Native.Integer64, as: ->
-    match Huia.Primitive.i64_compare(lhs: self, rhs: other),
+    match Huia.Primitive.i64_compare(self, other),
       1: -> true end,
       Any: -> false end
   end
 
   def greater_than? other: Native.Float64, as: ->
-    as_float = Huia.Primitive.i64_to_f64!(value: self)
-    match Huia.Primitive.f64_compare(lhs: as_float, rhs: other),
+    as_float = Huia.Primitive.i64_to_f64!(self)
+    match Huia.Primitive.f64_compare(as_float, other),
       1: -> true end,
       Any: -> false end
   end
@@ -31,15 +31,15 @@ defimpl Ordering for: Native.Integer64, as: ->
   def greater_than? other: Any, as: -> false
 
   def greater_than_or_equal_to? other: Native.Integer64, as: ->
-    match Huia.Primitive.i64_compare(lhs: self, rhs: other),
+    match Huia.Primitive.i64_compare(self, other),
       1: -> true end,
       0: -> true end,
       Any: -> false end
   end
 
   def greater_than_or_equal_to? other: Native.Float64, as: ->
-    as_float = Huia.Primitive.i64_to_f64!(value: self)
-    match Huia.Primitive.f64_compare(lhs: as_float, rhs: other),
+    as_float = Huia.Primitive.i64_to_f64!(self)
+    match Huia.Primitive.f64_compare(as_float, other),
       1: -> true end,
       Any: -> false end
   end
@@ -47,14 +47,14 @@ defimpl Ordering for: Native.Integer64, as: ->
   def greater_than_or_equal_to? other: Any, as: -> false
 
   def less_than? other: Native.Integer64, as: ->
-    match Huia.Primitive.i64_compare(lhs: self, rhs: other),
+    match Huia.Primitive.i64_compare(self, other),
       -1: -> true end,
       Any: -> false end
   end
 
   def less_than? other: Native.Float64, as: ->
-    as_float = Huia.Primitive.i64_to_f64!(value: self)
-    match Huia.Primitive.f64_compare(lhs: as_float, rhs: other),
+    as_float = Huia.Primitive.i64_to_f64!(self)
+    match Huia.Primitive.f64_compare(as_float, other),
       -1: -> true end,
       Any: -> false end
   end
@@ -62,15 +62,15 @@ defimpl Ordering for: Native.Integer64, as: ->
   def less_than? other: Any, as: -> false
 
   def less_than_or_equal_to? other: Native.Integer64, as: ->
-    match Huia.Primitive.i64_compare(lhs: self, rhs: other),
+    match Huia.Primitive.i64_compare(self, other),
       -1: -> true end,
       0: -> true end,
       Any: -> false end
   end
 
   def less_than_or_equal_to? other: Native.Float64, as: ->
-    as_float = Huia.Primitive.i64_to_f64!(value: self)
-    match Huia.Primitive.f64_compare(lhs: as_float, rhs: other),
+    as_float = Huia.Primitive.i64_to_f64!(self)
+    match Huia.Primitive.f64_compare(as_float, other),
       -1: -> true end,
       Any: -> false end
   end
diff --git a/packages/core/none.huia b/packages/core/none.huia
new file mode 100644
index 0000000..c2ca25c
--- /dev/null
+++ b/packages/core/none.huia
@@ -0,0 +1,7 @@
+deftype None as: ->
+
+  defstatic <None> new as: ->
+    None { }
+  end
+
+end
diff --git a/packages/core/none/option.huia b/packages/core/none/option.huia
new file mode 100644
index 0000000..fb97bfa
--- /dev/null
+++ b/packages/core/none/option.huia
@@ -0,0 +1,14 @@
+defimpl Option for: None, as: ->
+
+  def some? as: -> false end
+  def none? as: -> true end
+
+  def <Any> unwrap as: ->
+    Huia.Primitive.panic("Attempt to unwrap None")
+  end
+
+  def <Any> expect message: String, as: ->
+    Huia.Primitive.panic(message)
+  end
+
+end
diff --git a/packages/core/ok.huia b/packages/core/ok.huia
new file mode 100644
index 0000000..db9129a
--- /dev/null
+++ b/packages/core/ok.huia
@@ -0,0 +1,7 @@
+deftype Ok value: Any, as: ->
+
+  defstatic <Ok> new value: Any, as: ->
+    Ok { value: value }
+  end
+
+end
diff --git a/packages/core/ok/option.huia b/packages/core/ok/option.huia
new file mode 100644
index 0000000..11e69c2
--- /dev/null
+++ b/packages/core/ok/option.huia
@@ -0,0 +1,14 @@
+defimpl Option for: Ok, as: ->
+
+  def some? as: -> true end
+  def none? as: -> false end
+
+  def <Any> unwrap as: ->
+    @value
+  end
+
+  def <Any> expect message: String, as: ->
+    @value
+  end
+
+end
diff --git a/packages/core/ok/result.huia b/packages/core/ok/result.huia
new file mode 100644
index 0000000..a071c49
--- /dev/null
+++ b/packages/core/ok/result.huia
@@ -0,0 +1,14 @@
+defimpl Result for: Ok, as: ->
+
+  def ok? as: -> true end
+  def error? as: -> false end
+
+  def <Any> ok as: ->
+    @value
+  end
+
+  def <Any> error as: ->
+    Huia.Primitive.panic("Attempt to access error from Ok")
+  end
+
+end
diff --git a/packages/core/option.huia b/packages/core/option.huia
new file mode 100644
index 0000000..e4b6232
--- /dev/null
+++ b/packages/core/option.huia
@@ -0,0 +1,9 @@
+deftrait Option as: ->
+
+  def some?
+  def none?
+
+  def <Any> unwrap
+  def <Any> expect message: String
+
+end
diff --git a/packages/core/result.huia b/packages/core/result.huia
index 2e05a2a..f14bfaa 100644
--- a/packages/core/result.huia
+++ b/packages/core/result.huia
@@ -1,13 +1,9 @@
 deftrait Result as: ->
 
-  defstatic ok value: Any, as: -> Result.Ok.new(value)
-  defstatic error error: Error, as: -> Result.Error.new(error)
-  defstatic none as: -> Result.None.new()
-
   def ok?
   def error?
 
-  def <Any> unwrap
-  def <Any> expect message: String
+  def <Any> ok
+  def <Any> error
 
 end
diff --git a/packages/core/result/error.huia b/packages/core/result/error.huia
deleted file mode 100644
index 833b701..0000000
--- a/packages/core/result/error.huia
+++ /dev/null
@@ -1,20 +0,0 @@
-deftype Result.Error error: Error, as: ->
-
-  defstatic <Result.Error> new error: Error, as: ->
-    Result.Error{ error: error }
-  end
-
-end
-
-defimpl Result for: Result.Error, as: ->
-  def ok? as: -> false
-  def error? as: -> true
-
-  def <Any> unwrap as: ->
-    Huia.Primitive.panic_process(@error)
-  end
-
-  def <Any> expect message: String, as: ->
-    Huia.Primitive.panic_process(Error.new(message: message, cause: @error))
-  end
-end
diff --git a/packages/core/result/none.huia b/packages/core/result/none.huia
deleted file mode 100644
index f9d5e68..0000000
--- a/packages/core/result/none.huia
+++ /dev/null
@@ -1,20 +0,0 @@
-deftype Result.None value: Any, as: ->
-
-  defstatic <Result.None> new as: ->
-    Result.None { }
-  end
-
-end
-
-defimpl Result for: Result.None, as: ->
-  def ok? as: -> true
-  def error? as: -> false
-
-  def <Any> unwrap as: ->
-    Huia.Primitive.panic_process("Attempt to unwrap none")
-  end
-
-  def <Any> expect message: String, as: ->
-    Huia.Primitive.panic_process(Error.new(message: message))
-  end
-end
diff --git a/packages/core/result/ok.huia b/packages/core/result/ok.huia
deleted file mode 100644
index 8a043b6..0000000
--- a/packages/core/result/ok.huia
+++ /dev/null
@@ -1,14 +0,0 @@
-deftype Result.Ok value: Any, as: ->
-
-  defstatic <Result.Ok> new value: Any, as: ->
-    Result.Ok { value: value }
-  end
-
-end
-
-defimpl Result, for: Result.Ok, as: ->
-  def ok? as: -> true
-  def error? as: -> false
-  def <Any> unwrap as: -> @value
-  def <Any> expect as: -> @value
-end
diff --git a/packages/core/some.huia b/packages/core/some.huia
new file mode 100644
index 0000000..37a3bf0
--- /dev/null
+++ b/packages/core/some.huia
@@ -0,0 +1,7 @@
+deftype Some value: Any, as: ->
+
+  defstatic <Some> new value: Any, as: ->
+    Some { value: value }
+  end
+
+end
diff --git a/packages/core/some/option.huia b/packages/core/some/option.huia
new file mode 100644
index 0000000..d8d3d30
--- /dev/null
+++ b/packages/core/some/option.huia
@@ -0,0 +1,14 @@
+defimpl Option for: Some, as: ->
+
+  def some? as: -> true end
+  def none? as: -> false end
+
+  def <Any> unwrap as: ->
+    @value
+  end
+
+  def <Any> expect message: String, as: ->
+    @value
+  end
+
+end
diff --git a/parser/src/grammar.pest b/parser/src/grammar.pest
index a81bb3e..a8d8c9d 100644
--- a/parser/src/grammar.pest
+++ b/parser/src/grammar.pest
@@ -21,7 +21,7 @@ file                        = _{ soi ~ def* ~ eoi }
 // ####################################
 
 expression_test             = _{ soi ~ expression ~ eoi }
-expression                  = _{ literal ~ (binary_operator ~ literal)* }
+expression                  = _{ literal ~ (whitespace* ~ binary_operator ~ whitespace* ~ literal)* }
 
 
 // ####################################
@@ -32,7 +32,7 @@ atom                        = ${ ":" ~ identifier }
 boolean                     = _{ boolean_true | boolean_false }
 boolean_true                =  { "true" }
 boolean_false               =  { "false" }
-literal                     = _{ unary | constructor | list | integer | float | string | atom | property | identifier | braced | boolean }
+literal                     = _{ unary | call | constructor | list | integer | float | string | atom | property | variable | braced | boolean }
 braced                      = !{ "(" ~ expression ~ ")" }
 list                        = !{ "[" ~ (expression ~ ("," ~ expression)*)? ~ "]" }
 unary                       = ${ unary_operator ~ literal }
@@ -67,11 +67,10 @@ identifier_tail             = @{ ('a'..'z' | 'A'..'Z' | "_" | '0'..'9')+ }
 // ####################################
 
 block_test                  = _{ soi ~ block ~ eoi }
-block                       = @{ block_stabby ~ space* ~ (block_multi_line | block_single_line) }
+block                       = @{ block_stabby ~ whitespace+ ~ (block_end | block_body) }
 block_stabby                = _{ "->" }
-block_single_line           = _{ block_end | block_single_expression }
-block_single_expression     = _{ expression ~ space+ ~ block_end }
-block_multi_line            = _{ padded_newline+ ~ ((def | expression) ~ padded_newline+)* ~ block_end  }
+block_body                  = _{ block_expression ~ (padded_newline+ ~ block_expression)* ~ whitespace* ~ block_end }
+block_expression            = _{ def | expression }
 block_end                   = _{ "end" ~ !identifier_tail }
 
 
@@ -86,7 +85,7 @@ integer_hexadecimal         =  { ('0'..'9' | 'a'..'f' | 'A'..'F') ~ ('0'..'9' |
 integer_hexadecimal_sigil   = _{ "0x" ~ integer_hexadecimal }
 integer_octal               =  { ('0'..'7') ~ ('0'..'7' | "_" )* }
 integer_octal_sigil         = _{ "0o" ~ integer_octal }
-integer_binary              =  { ("0" | "1") ~ ("0" | "1" | "_")* }
+integer_binary              =  { ('0'..'1') ~ ('0'..'1' | "_")* }
 integer_binary_sigil        = _{ "0b" ~ integer_binary }
 integer_zero                =  { "0" }
 
@@ -119,9 +118,9 @@ string_escape               = _{ "\\" ~ ("\"" | "\\" | "/" | "b" | "f" | "n" | "
 // ####################################
 
 argument_list               = _{ argument_pair ~ ("," ~ argument_pair)* }
-argument_pair               =  { argument_keyword ~ argument_value }
+argument_pair               = !{ argument_keyword ~ argument_value }
 argument_keyword            = ${ identifier ~ ":" }
-argument_value              = _{ block | def_fn | expression }
+argument_value              = _{ block | expression }
 
 
 // ####################################
@@ -138,7 +137,10 @@ def_public                  =  { "def" }
 def_trait                   =  { "deftrait" }
 def_type                    =  { "deftype" }
 def_impl                    =  { "defimpl" }
-def_name                    =  { identifier }
+def_name                    = ${ identifier ~ def_modifier? }
+def_predicate               =  { "?" }
+def_bang                    =  { "!" }
+def_modifier                = _{ def_predicate | def_bang }
 def_return_type             =  { "<" ~ identifier ~ ">" }
 def_fn                      = _{ def_fn_keyword ~ def_return_type? ~ def_name ~ argument_list? }
 def_ty                      = _{ def_type_keyword ~ def_name ~ argument_list? }
@@ -182,3 +184,14 @@ binary_operator             =  {
                                }
 unary_operator              =  { plus | minus | logical_not }
 
+
+// ####################################
+// ## METHOD CALLS
+// ####################################
+
+call_test                   = _{ soi ~ call ~ eoi }
+call                        = ${ call_receiver ~ "." ~ call_name ~ call_arguments }
+call_receiver               =  { identifier }
+call_name                   =  { identifier }
+call_arguments              = !{ "(" ~ (call_argument ~ ("," ~ call_argument)*)? ~ ")" }
+call_argument               =  { expression }
diff --git a/parser/src/grammar/test/acceptance.huia b/parser/src/grammar/test/acceptance.huia
index 358d9ae..b077cec 100644
--- a/parser/src/grammar/test/acceptance.huia
+++ b/parser/src/grammar/test/acceptance.huia
@@ -1,7 +1,9 @@
 deftype Delorean speed: Integer, as: ->
+
   defstatic <Delorean> new as: ->
     Delorean { speed: 0 }
   end
+
 end
 
 deftrait Car as: ->
@@ -19,5 +21,5 @@ defimpl Car for: Delorean, as: ->
 end
 
 defimpl TimeMachine for: Delorean, as: ->
-  def travelling_through_time? as: -> @speed >= 88
+  def travelling_through_time? as: -> @speed >= 88 end
 end
diff --git a/parser/src/grammar/test/block.rs b/parser/src/grammar/test/block.rs
index 29f2a5a..fb009ef 100644
--- a/parser/src/grammar/test/block.rs
+++ b/parser/src/grammar/test/block.rs
@@ -47,7 +47,7 @@ fn multi_expression() {
 }
 
 #[test]
-fn constructor() {
+fn with_constructor() {
     parses_to!(
         parser: Grammar,
         input: r#"->
diff --git a/parser/src/grammar/test/call.rs b/parser/src/grammar/test/call.rs
new file mode 100644
index 0000000..cdd235d
--- /dev/null
+++ b/parser/src/grammar/test/call.rs
@@ -0,0 +1,36 @@
+use grammar::{Grammar, Rule};
+
+#[test]
+fn call_no_args() {
+    parses_to!(
+        parser: Grammar,
+        input: "marty.mcfly( )",
+        rule: Rule::call_test,
+        tokens: [
+            call(0, 14, [
+                call_receiver(0, 5, [identifier(0, 5)]),
+                call_name(6, 11, [identifier(6, 11)]),
+                call_arguments(11, 14)
+            ])
+        ]
+    )
+}
+
+#[test]
+fn call_with_args() {
+    parses_to!(
+        parser: Grammar,
+        input: "marty.mcfly( :hello, 88 )",
+        rule: Rule::call_test,
+        tokens: [
+            call(0, 25, [
+                call_receiver(0, 5, [identifier(0, 5)]),
+                call_name(6, 11, [identifier(6, 11)]),
+                call_arguments(11, 25, [
+                    call_argument(13, 19, [atom(13, 19, [identifier(14, 19)])]),
+                    call_argument(21, 24, [integer(21, 23, [integer_decimal(21, 23)])])
+                ]),
+            ])
+        ]
+    )
+}
diff --git a/parser/src/grammar/test/def.rs b/parser/src/grammar/test/def.rs
index 3fb27a6..1e6b7fb 100644
--- a/parser/src/grammar/test/def.rs
+++ b/parser/src/grammar/test/def.rs
@@ -48,7 +48,7 @@ fn define_return_type_with_args() {
                 def_name(16, 29, [identifier(16, 29)]),
                 argument_pair(30, 42, [
                     argument_keyword(30, 35, [identifier(30, 34)]),
-                    identifier(36, 42)
+                    variable(36, 42, [identifier(36, 42)])
                 ]),
                 argument_pair(44, 51, [
                     argument_keyword(44, 47, [identifier(44, 46)]),
@@ -71,7 +71,7 @@ fn define_with_args() {
                 def_name(4, 17, [identifier(4, 17)]),
                 argument_pair(18, 30, [
                     argument_keyword(18, 23, [identifier(18, 22)]),
-                    identifier(24, 30)
+                    variable(24, 30, [identifier(24, 30)])
                 ]),
                 argument_pair(32, 39, [
                     argument_keyword(32, 35, [identifier(32, 34)]),
@@ -163,8 +163,8 @@ fn def_trait_with_args() {
                         identifier(17, 25)
                     ]),
                     list(27, 49, [
-                        identifier(28, 36),
-                        identifier(38, 48)
+                        variable(28, 36, [identifier(28, 36)]),
+                        variable(38, 48, [identifier(38, 48)])
                     ])
                 ])
             ])
diff --git a/parser/src/grammar/test/mod.rs b/parser/src/grammar/test/mod.rs
index c4602b0..6cd1175 100644
--- a/parser/src/grammar/test/mod.rs
+++ b/parser/src/grammar/test/mod.rs
@@ -1,6 +1,7 @@
 mod acceptance;
 mod binary;
 mod block;
+mod call;
 mod def;
 mod float;
 mod identifier;