Fix Bug In Struct Field Initialization

Fields were not given default values when a struct was declared
without initializers.

Also, cleanup code in the helper function for binary operations
on struct instances.

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

Sources/Common/ProgramTypes.swift

@@ -186,23 +186,25 @@ public class P4StructValue: P4Value {
     // Note: Because the number of values _always_ matches the number of fields, there
     // is no need to check there!
 
-    for xx in zip(zip(lhs.stype.fields, lhs.values), zip(rhs.stype.fields, rhs.values)) {
-      let left = xx.0
-      let right = xx.1
+    for fields_to_compare in zip(
+      zip(lhs.stype.fields, lhs.values), zip(rhs.stype.fields, rhs.values))
+    {
+      let left_field_and_value = fields_to_compare.0
+      let right_field_and_value = fields_to_compare.1
 
-      let left_field = left.0
-      let left_value = left.1
+      let left_field_name = left_field_and_value.0
+      let left_field_value = left_field_and_value.1
 
-      let right_field = right.0
-      let right_value = right.1
+      let right_field_name = right_field_and_value.0
+      let right_field_value = right_field_and_value.1
 
       // If the field names do not match, then there is a problem.
-      if left_field != right_field {
+      if left_field_name != right_field_name {
         return false
       }
 
       // Now that we know that the field names match, do the values match?
-      if !op(left_value, right_value) {
+      if !op(left_field_value, right_field_value) {
         return false
       }
     }
@@ -296,17 +298,21 @@ public class P4StructValue: P4Value {
   }
 
   public let stype: P4Struct
-  public let values: [P4Value?]
+  public let values: [P4Value]
 
   public convenience init(withType type: P4Struct) {
     self.init(withType: type, andInitializers: [])
   }
 
   public init(withType type: P4Struct, andInitializers initializers: [P4Value?]) {
-    var values: [P4Value?] = Array(repeating: .none, count: type.fields.count())
-
-    for i in 0..<initializers.count {
-      values[i] = initializers[i]
+    let values = zip(0..<type.fields.count(), type.fields.fields).map { (index, field) in
+      // If there is an initializer for the field, then use it.
+      if index < initializers.count, let initializer = initializers[index] {
+        initializer
+      } else {
+        // Otherwise, set a default!
+        field.type.def()
+      }
     }
 
     self.values = values

Sources/P4Compiler/Declarations.swift

@@ -106,7 +106,6 @@ struct StructDeclaration {
 
     if currentChild!.nodeType == "struct_declaration_fields" {
       currentChild!.enumerateNamedChildren { declaration_field in
-        print("declaration field: \(declaration_field)")
         switch VariableDeclarationStatement.Compile(
           node: declaration_field, withContext: current_context)
         {

Sources/P4Compiler/Expression.swift

@@ -255,33 +255,33 @@ extension SelectExpression: CompilableExpression {
         ))
     }
 
-    var kses: [SelectCaseExpression] = Array()
-    var kses_errors: [Error] = Array()
+    var sces: [SelectCaseExpression] = Array()
+    var sces_errors: [Error] = Array()
 
     select_body_node.enumerateNamedChildren { current_node in
-      let maybe_parsed_kse = SelectCaseExpression.compile(
+      let maybe_parsed_cse = SelectCaseExpression.compile(
         node: current_node, withContext: context)
-      if case .Ok(let parsed_kse) = maybe_parsed_kse {
-        let parsed_cse = parsed_kse as! SelectCaseExpression
+      if case .Ok(let parsed_cse) = maybe_parsed_cse {
+        let parsed_cse = parsed_cse as! SelectCaseExpression
         switch parsed_cse.update_type(to: selector.type()) {
-        case .Ok(let updated_cse): kses.append(updated_cse)
-        case .Error(let e): kses_errors.append(ErrorOnNode(node: current_node, withError: e.msg))
+        case .Ok(let updated_cse): sces.append(updated_cse)
+        case .Error(let e): sces_errors.append(ErrorOnNode(node: current_node, withError: e.msg))
         }
       } else {
-        kses_errors.append(Error(withMessage: "\(maybe_parsed_kse.error()!)"))
+        sces_errors.append(Error(withMessage: "\(maybe_parsed_cse.error()!)"))
       }
     }
 
-    if !kses_errors.isEmpty {
+    if !sces_errors.isEmpty {
       return .Error(
         Error(
           withMessage: "Error(s) parsing select cases: "
-            + (kses_errors.map { error in
+            + (sces_errors.map { error in
               return "\(error.msg)"
             }.joined(separator: ";"))))
     }
     return .Ok(
-      SelectExpression(withSelector: selector, withSelectCaseExpressions: kses),
+      SelectExpression(withSelector: selector, withSelectCaseExpressions: sces),
     )
   }
 }

Sources/P4Compiler/Types.swift

@@ -56,8 +56,6 @@ extension P4Struct: CompilableType {
       return .Error(maybe_parsed_type_id.error()!)
     }
 
-    print("Looking up \(parsed_type_id) in \(context.types)")
-
     if case .Ok(let found_type) = context.types.lookup(identifier: parsed_type_id),
       let found_struct_type = found_type as? P4Struct
     {

Sources/P4Lang/Expressions.swift

@@ -145,10 +145,10 @@ public struct SelectExpression {
 
   public init(
     withSelector selector: EvaluatableExpression,
-    withSelectCaseExpressions kses: [SelectCaseExpression]
+    withSelectCaseExpressions sces: [SelectCaseExpression]
   ) {
     self.selector = selector
-    self.select_expressions = kses
+    self.select_expressions = sces
   }
 
   public func append_checked_sce(sce: SelectCaseExpression) -> SelectExpression {

Sources/P4Runtime/Expressions.swift

@@ -33,11 +33,11 @@ extension SelectExpression: EvaluatableExpression {
   public func evaluate(execution: Common.ProgramExecution) -> Common.Result<any Common.P4Value> {
     switch self.selector.evaluate(execution: execution) {
     case .Ok(let selector_value):
-      for kse in self.select_expressions {
-        if case .Ok(let kse_key) = kse.key.evaluate(execution: execution),
-          kse_key.eq(rhs: selector_value)
+      for sce in self.select_expressions {
+        if case .Ok(let kse) = sce.key.evaluate(execution: execution),
+          kse.eq(rhs: selector_value)
         {
-          let result = kse.evaluate(execution: execution)
+          let result = sce.evaluate(execution: execution)
           return result
         }
       }