compiler, runtime, common, documentation: Refactor Type System

The type system (and the value system) now include attributes
for each type (things like direction, const-ness).

Signed-off-by: Will Hawkins <hawkinsw@obs.cr>

Sources/P4Lang/Common.swift

@@ -19,36 +19,29 @@ import Common
 
 public struct Parameter: CustomStringConvertible, Equatable {
   public static func == (lhs: Parameter, rhs: Parameter) -> Bool {
-    return lhs.name == rhs.name && lhs.type.eq(rhs: rhs.type) && lhs.direction == rhs.direction
+    return lhs.name == rhs.name && lhs.type.eq(rhs.type)
   }
 
   public var name: Identifier
   public var type: P4Type
-  public var direction: Direction?
 
   public init(
-    identifier: Identifier, withType type: P4Type, withDirection direction: Direction? = .none
+    identifier: Identifier, withType type: P4Type
   ) {
     self.name = identifier
     self.type = type
-    self.direction = direction
   }
 
   public var description: String {
-    let direction = self.direction != .none ? self.direction!.description : "no"
-    return "Parameter: \(self.name) with type \(self.type) with \(direction) direction"
+    return "Parameter: \(self.name) with type \(self.type)"
   }
 
   /// Calculate whether the `argument` is compatible with this parameter.
   public func compatible(_ argument: Argument) -> Bool {
     let arg_type = argument.argument.type()
-    return arg_type.eq(rhs: self.type)
+    return arg_type.eq(self.type)
   }
 
-  public func attributedType() -> P4TypeAttributed {
-    return P4TypeAttributed(
-      self.type, self.direction == .none ? [] : [P4TypeAttribute.Direction(self.direction!)])
-  }
 }
 
 public struct ParameterList: CustomStringConvertible, Equatable {