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/Common.swift

@@ -1,95 +0,0 @@
-// p4rse, Copyright 2026, Will Hawkins
-//
-// This file is part of p4rse.
-//
-// This file is free software: you can redistribute it and/or modify
-// it under the terms of the GNU General Public License as published by
-// the Free Software Foundation, either version 3 of the License, or
-// (at your option) any later version.
-//
-// This program is distributed in the hope that it will be useful,
-// but WITHOUT ANY WARRANTY; without even the implied warranty of
-// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-// GNU General Public License for more details.
-//
-// You should have received a copy of the GNU General Public License
-// along with this program. If not, see <https://www.gnu.org/licenses/>.
-
-import Common
-
-public protocol Visitable {
-
-}
-
-public protocol LanguageVisitor<Context> {
-  associatedtype Context
-
-  // Program
-  func visit(_ program: Program, _ c: VisitorContext<Context>) -> Result<VisitorContext<Context>>
-
-  // Parser
-  func visit(_ parser: Parser, _ c: VisitorContext<Context>) -> Result<VisitorContext<Context>>
-  func visit(
-    _ parser_state: InstantiatedParserState, _ c: VisitorContext<Context>
-  ) -> Result<VisitorContext<Context>>
-
-  // Statements
-  func visit(
-    _ variable_declaration: VariableDeclarationStatement, _ c: VisitorContext<Context>
-  ) -> Result<VisitorContext<Context>>
-  func visit(
-    _ conditional: ConditionalStatement, _ c: VisitorContext<Context>
-  ) -> Result<VisitorContext<Context>>
-  func visit(
-    _ block: BlockStatement, _ c: VisitorContext<Context>
-  ) -> Result<VisitorContext<Context>>
-  func visit(
-    _ rtn: ReturnStatement, _ c: VisitorContext<Context>
-  ) -> Result<VisitorContext<Context>>
-  func visit(
-    _ apply: ApplyStatement, _ c: VisitorContext<Context>
-  ) -> Result<VisitorContext<Context>>
-
-  // Expressions
-  func visit(
-    _ keyset: KeysetExpression, _ c: VisitorContext<Context>
-  ) -> Result<VisitorContext<Context>>
-  func visit(
-    _ select_case: SelectCaseExpression, _ c: VisitorContext<Context>
-  ) -> Result<VisitorContext<Context>>
-  func visit(
-    _ select: SelectExpression, _ c: VisitorContext<Context>
-  ) -> Result<VisitorContext<Context>>
-  func visit(
-    _ array_access: ArrayAccessExpression, _ c: VisitorContext<Context>
-  ) -> Result<VisitorContext<Context>>
-  func visit(
-    _ field_access: FieldAccessExpression, _ c: VisitorContext<Context>
-  ) -> Result<VisitorContext<Context>>
-  func visit(
-    _ function_call: FunctionCall, _ c: VisitorContext<Context>
-  ) -> Result<VisitorContext<Context>>
-  func visit(
-    _ binary_operator: BinaryOperatorExpression, _ c: VisitorContext<Context>
-  ) -> Result<VisitorContext<Context>>
-
-  // Declarations
-  func visit(_ decl: Declaration, _ c: VisitorContext<Context>) -> Result<VisitorContext<Context>>
-  func visit(
-    _ extern_decl: ExternDeclaration, _ c: VisitorContext<Context>
-  ) -> Result<VisitorContext<Context>>
-  func visit(
-    _ func_decl: FunctionDeclaration, _ c: VisitorContext<Context>
-  ) -> Result<VisitorContext<Context>>
-
-  // Control
-  func visit(_ action: Action, _ c: VisitorContext<Context>) -> Result<VisitorContext<Context>>
-  func visit(
-    _ table_key_entry: TableKeyEntry, _ c: VisitorContext<Context>
-  ) -> Result<VisitorContext<Context>>
-  func visit(
-    _ table_property_list: TablePropertyList, _ c: VisitorContext<Context>
-  ) -> Result<VisitorContext<Context>>
-  func visit(_ table: Table, _ c: VisitorContext<Context>) -> Result<VisitorContext<Context>>
-  func visit(_ control: Control, _ c: VisitorContext<Context>) -> Result<VisitorContext<Context>>
-}

Sources/P4Lang/Declarations.swift

@@ -52,7 +52,7 @@ public struct Declaration: P4Type {
     return self
   }
   public var description: String {
-    return "Extern \(self.identifier)"
+    return self.extern ? "Extern " : "" + "\(self.identifier)"
   }
 }
 
@@ -130,3 +130,15 @@ public struct FunctionDeclaration: P4Type, P4DataValue {
     self.body = body
   }
 }
+
+public struct Instantiation {
+  public let name: Identifier
+  public let tipe: P4Type
+  public let arguments: ArgumentList
+
+  public init(named name: Identifier, ofType tipe: P4Type, withArguments arguments: ArgumentList) {
+    self.name = name
+    self.tipe = tipe
+    self.arguments = arguments
+  }
+}

Sources/P4Lang/Expressions.swift

@@ -18,9 +18,9 @@
 import Common
 
 public struct KeysetExpression {
-  public let key: EvaluatableExpression
+  public let key: P4Expression
 
-  public init(_ key: EvaluatableExpression) {
+  public init(_ key: P4Expression) {
     self.key = key
   }
 
@@ -65,11 +65,11 @@ public struct SelectCaseExpression {
 }
 
 public struct SelectExpression {
-  public let selector: EvaluatableExpression
+  public let selector: P4Expression
   public let case_expressions: [SelectCaseExpression]
 
   public init(
-    withSelector selector: EvaluatableExpression,
+    withSelector selector: P4Expression,
     withSelectCaseExpressions sces: [SelectCaseExpression]
   ) {
     self.selector = selector
@@ -105,13 +105,13 @@ public struct BinaryOperatorExpression {
 }
 
 public struct ArrayAccessExpression {
-  public let indexor: EvaluatableExpression
-  public let name: EvaluatableExpression
+  public let indexor: P4Expression
+  public let name: P4Expression
   public let type: P4Array
 
   public init(
-    withName name: EvaluatableExpression, withType type: P4Array,
-    withIndexor indexor: EvaluatableExpression
+    withName name: P4Expression, withType type: P4Array,
+    withIndexor indexor: P4Expression
   ) {
     self.name = name
     self.type = type
@@ -121,9 +121,9 @@ public struct ArrayAccessExpression {
 
 public struct FieldAccessExpression {
   public let field: P4StructFieldIdentifier
-  public let strct: EvaluatableExpression
+  public let strct: P4Expression
 
-  public init(withStruct strct: EvaluatableExpression, withField field: P4StructFieldIdentifier) {
+  public init(withStruct strct: P4Expression, withField field: P4StructFieldIdentifier) {
     self.strct = strct
     self.field = field
   }

Sources/P4Lang/Parser.swift

@@ -22,11 +22,11 @@ public struct LocalElements {}
 public struct LocalElement {}
 
 public struct ParserAssignmentStatement {
-  public let lvalue: EvaluatableLValueExpression
-  public let value: EvaluatableExpression
+  public let lvalue: P4LValueExpression
+  public let value: P4Expression
 
   public init(
-    withLValue lvalue: EvaluatableLValueExpression, withValue value: EvaluatableExpression
+    withLValue lvalue: P4LValueExpression, withValue value: P4Expression
   ) {
     self.lvalue = lvalue
     self.value = value
@@ -34,12 +34,9 @@ public struct ParserAssignmentStatement {
 }
 
 /// A P4 Parser State
-///
-/// Note: A P4 Parser State is both a type and a value.
-/// This "bare" parser state represents the state more as a type than a value.
 public class ParserState: P4Type, Equatable, CustomStringConvertible {
   let name: Identifier
-  public let statements: [EvaluatableStatement]
+  public let statements: [P4Statement]
 
   public static func == (lhs: ParserState, rhs: ParserState) -> Bool {
     return lhs.eq(rhs: rhs)
@@ -60,12 +57,12 @@ public class ParserState: P4Type, Equatable, CustomStringConvertible {
     return self.name
   }
 
-  public func getStatements() -> [EvaluatableStatement] {
+  public func getStatements() -> [P4Statement] {
     return self.statements
   }
 
   /// Construct a ParserState
-  public init(_ name: Identifier, _ statements: [EvaluatableStatement] = Array()) {
+  public init(_ name: Identifier, _ statements: [P4Statement] = Array()) {
     self.name = name
     self.statements = statements
   }
@@ -100,7 +97,7 @@ public class ParserStateDirectTransition: ParserState {
   /// Construct a ParserState
   public init(
     name: Identifier, withNextState next_state: InstantiatedParserState,
-    withStatements stmts: [EvaluatableStatement] = Array(),
+    withStatements stmts: [P4Statement] = Array(),
   ) {
     self.next_state = next_state
     self.next_state_identifier = .none
@@ -109,7 +106,7 @@ public class ParserStateDirectTransition: ParserState {
 
   public init(
     name: Identifier, withNextStateIdentifier next_state_id: Identifier,
-    withStatements stmts: [EvaluatableStatement] = Array(),
+    withStatements stmts: [P4Statement] = Array(),
   ) {
     self.next_state = .none
     self.next_state_identifier = next_state_id
@@ -129,7 +126,7 @@ public class ParserStateDirectTransition: ParserState {
 public class ParserStateNoTransition: ParserState {
   /// Construct a ParserState
   public init(
-    name: Identifier, withStatements stmts: [EvaluatableStatement] = Array(),
+    name: Identifier, withStatements stmts: [P4Statement] = Array(),
   ) {
     super.init(name, stmts)
   }
@@ -145,7 +142,7 @@ public class ParserStateSelectTransition: ParserState {
 
   public init(
     name: Identifier, withTransitionExpression te: SelectExpression,
-    withStatements stmts: [EvaluatableStatement] = Array()
+    withStatements stmts: [P4Statement] = Array()
   ) {
     self.te = te
     super.init(name, stmts)

Sources/P4Lang/Program.swift

@@ -18,9 +18,9 @@
 import Common
 
 public struct ExpressionStatement {
-  public let expression: EvaluatableExpression
+  public let expression: P4Expression
 
-  public init(_ expr: EvaluatableExpression) {
+  public init(_ expr: P4Expression) {
     self.expression = expr
   }
 }

Sources/P4Lang/Protocols.swift

@@ -0,0 +1,95 @@
+// p4rse, Copyright 2026, Will Hawkins
+//
+// This file is part of p4rse.
+//
+// This file is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see <https://www.gnu.org/licenses/>.
+
+import Common
+
+public protocol Visitable {
+
+}
+
+public protocol LanguageVisitor<Context> {
+  associatedtype Context
+
+  // Program
+  func visit(_ program: Program, _ c: VisitorContext<Context>) -> Result<VisitorContext<Context>>
+
+  // Parser
+  func visit(_ parser: Parser, _ c: VisitorContext<Context>) -> Result<VisitorContext<Context>>
+  func visit(
+    _ parser_state: InstantiatedParserState, _ c: VisitorContext<Context>
+  ) -> Result<VisitorContext<Context>>
+
+  // Statements
+  func visit(
+    _ variable_declaration: VariableDeclarationStatement, _ c: VisitorContext<Context>
+  ) -> Result<VisitorContext<Context>>
+  func visit(
+    _ conditional: ConditionalStatement, _ c: VisitorContext<Context>
+  ) -> Result<VisitorContext<Context>>
+  func visit(
+    _ block: BlockStatement, _ c: VisitorContext<Context>
+  ) -> Result<VisitorContext<Context>>
+  func visit(
+    _ rtn: ReturnStatement, _ c: VisitorContext<Context>
+  ) -> Result<VisitorContext<Context>>
+  func visit(
+    _ apply: ApplyStatement, _ c: VisitorContext<Context>
+  ) -> Result<VisitorContext<Context>>
+
+  // Expressions
+  func visit(
+    _ keyset: KeysetExpression, _ c: VisitorContext<Context>
+  ) -> Result<VisitorContext<Context>>
+  func visit(
+    _ select_case: SelectCaseExpression, _ c: VisitorContext<Context>
+  ) -> Result<VisitorContext<Context>>
+  func visit(
+    _ select: SelectExpression, _ c: VisitorContext<Context>
+  ) -> Result<VisitorContext<Context>>
+  func visit(
+    _ array_access: ArrayAccessExpression, _ c: VisitorContext<Context>
+  ) -> Result<VisitorContext<Context>>
+  func visit(
+    _ field_access: FieldAccessExpression, _ c: VisitorContext<Context>
+  ) -> Result<VisitorContext<Context>>
+  func visit(
+    _ function_call: FunctionCall, _ c: VisitorContext<Context>
+  ) -> Result<VisitorContext<Context>>
+  func visit(
+    _ binary_operator: BinaryOperatorExpression, _ c: VisitorContext<Context>
+  ) -> Result<VisitorContext<Context>>
+
+  // Declarations
+  func visit(_ decl: Declaration, _ c: VisitorContext<Context>) -> Result<VisitorContext<Context>>
+  func visit(
+    _ extern_decl: ExternDeclaration, _ c: VisitorContext<Context>
+  ) -> Result<VisitorContext<Context>>
+  func visit(
+    _ func_decl: FunctionDeclaration, _ c: VisitorContext<Context>
+  ) -> Result<VisitorContext<Context>>
+
+  // Control
+  func visit(_ action: Action, _ c: VisitorContext<Context>) -> Result<VisitorContext<Context>>
+  func visit(
+    _ table_key_entry: TableKeyEntry, _ c: VisitorContext<Context>
+  ) -> Result<VisitorContext<Context>>
+  func visit(
+    _ table_property_list: TablePropertyList, _ c: VisitorContext<Context>
+  ) -> Result<VisitorContext<Context>>
+  func visit(_ table: Table, _ c: VisitorContext<Context>) -> Result<VisitorContext<Context>>
+  func visit(_ control: Control, _ c: VisitorContext<Context>) -> Result<VisitorContext<Context>>
+}

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
   }
 }