Add first sketch of the interpreter

msm/src/serialization/interpreter.rs

@@ -0,0 +1,23 @@
+pub trait InterpreterEnv {
+    type Position;
+
+    type Variable;
+
+    /// Check that the value is in the range [0, 2^15-1]
+    fn range_check15(&mut self, _value: &Self::Variable) {
+        // TODO
+    }
+
+    /// Check that the value is in the range [0, 2^4-1]
+    fn range_check4(&mut self, _value: &Self::Variable) {
+        // TODO
+    }
+
+    /// Deserialize the next field element given as input
+    fn deserialize_field_element(&mut self);
+
+    /// Copy the value `value` in the column `position`
+    fn copy(&mut self, _position: Self::Position, _value: Self::Variable) {
+        // TODO
+    }
+}

msm/src/serialization/mod.rs

@@ -1 +1,2 @@
 pub mod columns;
+pub mod interpreter;