compiler, runtime: Begin Runtime Refactor

Ultimately, the goal is to completely separate the compilation from
the runtime to make it possible to have the interpreter/evaluator
be "just another" entity that can perform meaningful work when
given a parsed GP4 program.

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

Sources/P4Lang/Statement.swift

@@ -20,28 +20,28 @@ import Common
 public struct Statement {}
 
 public struct VariableDeclarationStatement {
-  public var initializer: EvaluatableExpression
-  public var identifier: Identifier
-  public init(identifier: Identifier, withInitializer initializer: EvaluatableExpression) {
+  public var initializer: P4Expression
+  public var identifier: TypedIdentifier
+  public init(identifier: TypedIdentifier, withInitializer initializer: P4Expression) {
     self.identifier = identifier
     self.initializer = initializer
   }
 }
 
 public struct ConditionalStatement {
-  public var condition: EvaluatableExpression
-  public var thenn: EvaluatableStatement
-  public var elss: EvaluatableStatement?
+  public var condition: P4Expression
+  public var thenn: P4Statement
+  public var elss: P4Statement?
 
-  public init(condition: EvaluatableExpression, withThen thenn: EvaluatableStatement) {
+  public init(condition: P4Expression, withThen thenn: P4Statement) {
     self.condition = condition
     self.thenn = thenn
     self.elss = .none
   }
 
   public init(
-    condition: EvaluatableExpression, withThen thenn: EvaluatableStatement,
-    andElse elss: EvaluatableStatement
+    condition: P4Expression, withThen thenn: P4Statement,
+    andElse elss: P4Statement
   ) {
     self.condition = condition
     self.thenn = thenn
@@ -50,18 +50,18 @@ public struct ConditionalStatement {
 }
 
 public struct BlockStatement {
-  public var statements: [EvaluatableStatement]
+  public var statements: [P4Statement]
 
-  public init(_ statements: [EvaluatableStatement]) {
+  public init(_ statements: [P4Statement]) {
     self.statements = statements
   }
 
 }
 
 public struct ReturnStatement {
-  public let value: EvaluatableExpression
+  public let value: P4Expression
 
-  public init(_ value: EvaluatableExpression) {
+  public init(_ value: P4Expression) {
     self.value = value
   }
 }