Start Handling Control Blocks

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

README.md

@@ -9,9 +9,20 @@ Very, very alpha:
 1. Limited parts of the language can be parsed.
 2. Limited programs can be evaluated.
 
-As an example of what can be parsed and evaluated, here is a fairly complex P4 program from our unit tests:
+As an example of what can be parsed and evaluated, here is a fairly complex P4 program cobbled together from our unit tests:
 
 ```P4
+control simple(bool x, bool y) {
+  action a(int z) {
+    z = false;
+  }
+  table t {
+    key = {
+      x: exact;
+      y: exact;
+    }
+  }
+};
 struct Testing {
   bool yesno;
   int count;

Sources/Common/ProgramTypes.swift

@@ -39,6 +39,10 @@ public class Identifier: CustomStringConvertible, Comparable, Hashable {
     return lhs.name == rhs.name
   }
 
+  public static func == (lhs: Identifier, rhs: String) -> Bool {
+    return Identifier(name: rhs) == lhs
+  }
+
   public static func < (lhs: Identifier, rhs: Identifier) -> Bool {
     return lhs.name < rhs.name
   }

Sources/P4Compiler/Declarations.swift

@@ -29,6 +29,7 @@ extension Declaration: CompilableDeclaration {
 
     let declaration_compilers: [String: CompilableDeclaration.Type] = [
       "function_declaration": FunctionDeclaration.self,
+      "control_declaration": Control.self,
       "type_declaration": StructDeclaration.self,  // Assume that type declarations are struct declarations.
     ]
 
@@ -556,3 +557,404 @@ extension Parameter: Compilable {
       ))
   }
 }
+
+extension Control: CompilableDeclaration {
+  public static func Compile(
+    node: SwiftTreeSitter.Node, withContext context: CompilerContext
+  ) -> Common.Result<(any Common.P4Type, CompilerContext)?> {
+
+    #SkipUnlessNodeType<Node, (P4Type, CompilerContext)?>(
+      node: node, type: "control_declaration")
+
+    var currentChildIdx = 0
+    var currentChildIdxSafe = 1
+    var currentChild: Node? = .none
+
+    var local_context = context
+
+    // Skip control keyword
+    if node.childCount < currentChildIdxSafe {
+      return .Error(
+        ErrorOnNode(node: node, withError: "Missing control declaration component"))
+    }
+
+    currentChildIdx += 1
+    currentChildIdxSafe += 1
+    if node.childCount < currentChildIdxSafe {
+      return .Error(
+        ErrorOnNode(node: node, withError: "Missing control declaration component"))
+    }
+    currentChild = node.child(at: currentChildIdx)
+
+    guard
+      case .Ok(let control_name) = Identifier.Compile(
+        node: currentChild!, withContext: local_context)
+    else {
+      return Result.Error(
+        Error(withMessage: "Could not parse a parameter name from \(currentChild!.text!)"))
+    }
+
+    currentChildIdx += 1
+    currentChildIdxSafe += 1
+    if node.childCount < currentChildIdxSafe {
+      return .Error(
+        ErrorOnNode(node: node, withError: "Missing control declaration component"))
+    }
+    currentChild = node.child(at: currentChildIdx)
+
+    let maybe_control_parameters = ParameterList.Compile(
+      node: currentChild!, withContext: local_context)
+    guard case .Ok((let control_parameters, let updated_context)) = maybe_control_parameters
+    else {
+      return .Error(maybe_control_parameters.error()!)
+    }
+    local_context = updated_context
+
+    // Before continuing, make sure to put the parameters into context.
+    var control_scope = local_context.instances.enter()
+    for parameter in control_parameters.parameters {
+      control_scope = control_scope.declare(identifier: parameter.name, withValue: parameter.type)
+    }
+    local_context = local_context.update(newInstances: control_scope)
+
+    // Skip the '{'
+    currentChildIdx += 2
+    currentChildIdxSafe += 2
+    if node.childCount < currentChildIdxSafe {
+      return .Error(
+        ErrorOnNode(node: node, withError: "Missing control declaration component"))
+    }
+
+    var actions: [Action] = Array()
+    var tables: [Table] = Array()
+
+    //                                                       Because the final child
+    //                                                       is the '}'.
+    //                                                        \/\/
+    for currentChildIdx in currentChildIdx..<(node.childCount - 1) {
+      let currentChild = node.child(at: currentChildIdx)!
+      if currentChild.nodeType == "action_declaration" {
+        let maybe_action_declaration = Action.Compile(
+          node: currentChild, withContext: local_context)
+        guard
+          case .Ok((let action_declaration, let updated_context)) = maybe_action_declaration
+        else {
+          return .Error(maybe_action_declaration.error()!)
+        }
+        actions.append(action_declaration)
+        local_context = updated_context
+      } else if currentChild.nodeType == "table_declaration" {
+        let maybe_table_declaration = Table.Compile(
+          node: currentChild, withContext: local_context)
+        guard
+          case .Ok((let table_declaration, let updated_context)) = maybe_table_declaration
+        else {
+          return .Error(maybe_table_declaration.error()!)
+        }
+        tables.append(table_declaration)
+        local_context = updated_context
+      } else {
+        return .Error(
+          ErrorOnNode(node: currentChild, withError: "Uknown node type in control declaration"))
+      }
+    }
+
+    // There should only be a single table!
+    // TODO: Check the semantics here.
+    if tables.count > 1 {
+      // TODO: Make this error message better.
+      // IDEA: Add a "compilation context" for the error message into the `CompilationContext`
+      // that can be retrieved to make the error messages nicer.
+      return .Error(ErrorOnNode(node: node, withError: "More than one table in control declaration"))
+    }
+
+    let declared_control =
+      (Control(
+        named: control_name, withParameters: control_parameters, withTable: tables[0],
+        withActions: Actions(withActions: actions))
+        as P4Type)
+
+    // Don't forget to add the newly declared Control to the instance that we were given
+    // (and not the one that we entered to do the parsing of this Control).
+    return .Ok(
+      (
+        declared_control,
+        context.update(
+          newInstances: context.instances.declare(
+            identifier: control_name, withValue: declared_control))
+      ))
+  }
+}
+
+extension Action: Compilable {
+  public typealias T = Action
+  public static func Compile(
+    node: SwiftTreeSitter.Node, withContext context: CompilerContext
+  ) -> Common.Result<(P4Lang.Action, CompilerContext)> {
+    #RequireNodeType<Node, (P4Type, CompilerContext)>(
+      node: node, type: "action_declaration", nice_type_name: "Action Declaration")
+
+    var currentChildIdx = 1
+    var currentChildIdxSafe = 2
+    var currentChild: Node? = .none
+    var current_context = context
+
+    // Skip action keyword
+    if node.childCount < currentChildIdxSafe {
+      return .Error(
+        ErrorOnNode(node: node, withError: "Missing action declaration component"))
+    }
+    currentChild = node.child(at: currentChildIdx)
+
+    guard
+      case .Ok(let action_name) = Identifier.Compile(
+        node: currentChild!, withContext: current_context)
+    else {
+      return Result.Error(
+        Error(withMessage: "Could not parse an action name from \(currentChild!.text!)"))
+    }
+
+    currentChildIdx += 1
+    currentChildIdxSafe += 1
+    if node.childCount < currentChildIdxSafe {
+      return .Error(
+        ErrorOnNode(node: node, withError: "Missing action declaration component"))
+    }
+    currentChild = node.child(at: currentChildIdx)
+
+    let maybe_action_parameters = ParameterList.Compile(
+      node: currentChild!, withContext: current_context)
+    guard case .Ok((let action_parameters, let updated_context)) = maybe_action_parameters
+    else {
+      return .Error(maybe_action_parameters.error()!)
+    }
+    current_context = updated_context
+
+    currentChildIdx += 1
+    currentChildIdxSafe += 1
+    if node.childCount < currentChildIdxSafe {
+      return Result.Error(
+        ErrorOnNode(
+          node: node, withError: "Missing action declaration component"))
+    }
+    currentChild = node.child(at: currentChildIdx)
+
+    // Add the parameters into scope.
+    var function_scope = context.instances.enter()
+    for parameter in action_parameters.parameters {
+      function_scope = function_scope.declare(identifier: parameter.name, withValue: parameter.type)
+    }
+
+    let maybe_action_body = Parser.Statement.Compile(
+      node: currentChild!, withContext: context.update(newInstances: function_scope))
+    guard case .Ok((let action_body, _)) = maybe_action_body else {
+      return .Error(maybe_action_body.error()!)
+    }
+
+    return .Ok(
+      (
+        Action(named: action_name, withParameters: action_parameters, withBody: action_body),
+        current_context
+      ))
+  }
+}
+
+extension TableKeyEntry: Compilable {
+    public typealias T = TableKeyEntry
+    public static func Compile(node: SwiftTreeSitter.Node, withContext context: CompilerContext) -> Common.Result<(P4Lang.TableKeyEntry, CompilerContext)> {
+
+    #RequireNodeType<Node, (P4Type, CompilerContext)>(node: node, type: "table_key_entry", nice_type_name: "Table Key Entry")
+
+    var currentChildIdx = 0
+    var currentChildIdxSafe = 1
+    var currentChild: Node? = .none
+
+    let current_context = context
+
+    if node.childCount < currentChildIdxSafe {
+      return .Error(
+        ErrorOnNode(node: node, withError: "Missing table key entry declaration component"))
+    }
+    currentChild = node.child(at: currentChildIdx)
+
+    let maybe_keyset_expression = KeysetExpression.compile(node: currentChild!, withContext: current_context)
+    guard case .Ok(let keyset_expression) = maybe_keyset_expression else {
+      return Result.Error(maybe_keyset_expression.error()!)
+    }
+
+    // Skip the ':'
+    currentChildIdx += 2
+    currentChildIdxSafe += 2
+    if node.childCount < currentChildIdxSafe {
+      return .Error(
+        ErrorOnNode(node: node, withError: "Missing table key entry declaration component"))
+    }
+    currentChild = node.child(at: currentChildIdx)
+
+    let maybe_match_type = TableKeyMatchType.Compile(node: currentChild!, withContext: current_context)
+    guard case .Ok((let match_type, _)) = maybe_match_type else {
+      return .Error(maybe_match_type.error()!)
+    }
+
+    return .Ok((TableKeyEntry(keyset_expression as! KeysetExpression, match_type), current_context))
+  }
+}
+
+extension TableKeyMatchType: Compilable {
+    public typealias T = TableKeyMatchType
+    public static func Compile(node: SwiftTreeSitter.Node, withContext context: CompilerContext) -> Common.Result<(P4Lang.TableKeyMatchType, CompilerContext)> {
+      #RequireNodeType<Node, (TableKeyMatchType, CompilerContext)>(node: node, type: "table_key_match_type", nice_type_name: "Table Key Match Type")
+
+      if node.text! == "exact" {
+        return .Ok((TableKeyMatchType.Exact, context))
+      }
+      return .Error(ErrorOnNode(node: node, withError: "\(node.text!) is not a valid match type)"))
+    }
+}
+
+extension TableKeys: Compilable {
+    public typealias T = TableKeys
+    public static func Compile(node: SwiftTreeSitter.Node, withContext context: CompilerContext) -> Common.Result<(P4Lang.TableKeys, CompilerContext)> {
+      #RequireNodeType<Node, (TableKeyMatchType, CompilerContext)>(node: node, type: "table_keys", nice_type_name: "Table Keys")
+
+    // Skip the 
+    // keys = {
+    // 0    1 2
+    let currentChildIdx = 3
+    let currentChildIdxSafe = 4
+    var currentChild: Node? = .none
+    var current_context = context
+
+    if node.childCount < currentChildIdxSafe {
+      return .Error(
+        ErrorOnNode(node: node, withError: "Missing table keys declaration component in control declaration"))
+    }
+    currentChild = node.child(at: currentChildIdx)
+
+    var entries: [TableKeyEntry] = Array()
+    var errors: [Error] = Array()
+
+    currentChild!.enumerateNamedChildren() { entry in
+      switch TableKeyEntry.Compile(node: currentChild!, withContext: current_context) {
+      case .Ok((let keyset_expression, let updated_context)):
+        entries.append(keyset_expression)
+        current_context = updated_context
+      case .Error(let e): errors.append(e)
+      }
+    }
+
+    if !errors.isEmpty {
+      return .Error(
+        Error(
+          withMessage: "Error(s) parsing table key: "
+            + (errors.map { error in
+              return "\(error.msg)"
+            }.joined(separator: ";"))))
+    }
+
+    return .Ok((TableKeys(withEntries: entries), current_context))
+  }
+}
+
+extension TablePropertyList: Compilable {
+    public typealias T = TablePropertyList
+  public static func Compile(
+    node: SwiftTreeSitter.Node, withContext context: CompilerContext
+  ) -> Common.Result<(P4Lang.TablePropertyList, CompilerContext)> {
+
+    #RequireNodeType<Node, (P4Type, CompilerContext)>(
+      node: node, type: "table_property_list", nice_type_name: "Table Property List")
+
+    var current_context = context
+
+    var keys: [TableKeys] = Array()
+    var _: [Action] = Array()  // Actions are not yet supported
+    var errors: [Error] = Array()
+
+    node.enumerateNamedChildren() { child in
+      if child.nodeType == "table_keys" {
+        switch TableKeys.Compile(node: child, withContext: current_context) {
+        case .Ok((let table_key, let updated_context)):
+          current_context = updated_context
+          keys.append(table_key)
+        case .Error(let e): errors.append(e)
+        }
+      } else if child.nodeType == "table_actions" {
+        errors.append(
+          ErrorOnNode(
+            node: child, withError: "Actions in table property lists are not yet supported"))
+      } else {
+        errors.append(
+          ErrorOnNode(node: child, withError: "Uknown node type in control declaration"))
+      }
+    }
+
+    if !errors.isEmpty {
+      return .Error(
+        Error(
+          withMessage: "Error(s) parsing property list: "
+            + (errors.map { error in
+              return "\(error.msg)"
+            }.joined(separator: ";"))))
+    }
+
+    // There should be only one table keys!
+    if keys.count > 1 {
+      // Todo: Make this error message better.
+      return .Error(
+        ErrorOnNode(node: node, withError: "More than one key set in table property list"))
+    }
+
+    return .Ok((TablePropertyList(withActions: TableActions(), withKeys: keys[0]), current_context))
+
+  }
+}
+
+extension Table: Compilable {
+    public typealias T = Table
+  public static func Compile(
+    node: SwiftTreeSitter.Node, withContext context: CompilerContext
+  ) -> Common.Result<(P4Lang.Table, CompilerContext)> {
+
+    let table_declaration_node = node
+    #RequireNodeType<Node, (P4Type, CompilerContext)>(
+      node: table_declaration_node, type: "table_declaration", nice_type_name: "Table Declaration")
+
+    var currentChildIdx = 1
+    var currentChildIdxSafe = 2
+    var currentChild: Node? = .none
+
+    let current_context = context
+
+    if table_declaration_node.childCount < currentChildIdxSafe {
+      return .Error(
+        ErrorOnNode(node: table_declaration_node, withError: "Missing table declaration component"))
+    }
+    currentChild = table_declaration_node.child(at: currentChildIdx)
+
+    guard
+      case .Ok(let table_name) = Identifier.Compile(
+        node: currentChild!, withContext: current_context)
+    else {
+      return Result.Error(
+        Error(withMessage: "Could not parse a table name from \(currentChild!.text!)"))
+    }
+
+    // Skip the '{'
+    currentChildIdx += 2
+    currentChildIdxSafe += 2
+    if table_declaration_node.childCount < currentChildIdxSafe {
+      return .Error(
+        ErrorOnNode(node: table_declaration_node, withError: "Missing table declaration component"))
+    }
+    currentChild = table_declaration_node.child(at: currentChildIdx)
+
+    let maybe_table_property_list = TablePropertyList.Compile(
+      node: currentChild!, withContext: current_context)
+    guard case .Ok((let table_property_list, _)) = maybe_table_property_list else {
+      return Result.Error(maybe_table_property_list.error()!)
+    }
+
+    return .Ok((Table(withName: table_name, withPropertyList: table_property_list), current_context))
+  }
+}

Sources/P4Lang/Control.swift

@@ -0,0 +1,211 @@
+// 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 struct Action: CustomStringConvertible {
+  public var description: String {
+    return "Action: " + "\(self.name) with parameters \(self.params) and body \(String(describing: self.body))"
+  }
+
+  public var body: EvaluatableStatement?
+  public var params: ParameterList
+  public var name: Identifier
+
+  public init(
+    named name: Identifier, withParameters parameters: ParameterList,
+    withBody body: EvaluatableStatement?
+  ) {
+    self.name = name
+    self.params = parameters
+    self.body = body
+  }
+
+}
+
+public struct Actions: CustomStringConvertible {
+  let actions: [Action]
+  public init(withActions actions: [Action]) {
+    self.actions = actions
+  }
+
+  public var description: String {
+    return "Actions: " + actions.map() {action in 
+      return "\(action)"
+    }.joined(separator: ";")
+  }
+}
+
+public enum TableKeyMatchType {
+  case Exact
+}
+
+public struct TableKeyEntry: CustomStringConvertible  {
+  let key: KeysetExpression
+  let match_type: TableKeyMatchType
+
+  public init(_ key: KeysetExpression, _ match: TableKeyMatchType) {
+    self.key = key
+    self.match_type = match
+  }
+
+  public var description: String {
+    return "Table Key Entry: " + "\(self.key): \(self.match_type)"
+  }
+}
+
+public struct TableKeys: CustomStringConvertible  {
+  let entries: [TableKeyEntry]
+
+  public init(withEntries entries: [TableKeyEntry]) {
+    self.entries = entries
+  }
+  public init() {
+    self.entries = []
+  }
+
+  public var description: String {
+    return "Table Keys: " + self.entries.map() { entry in 
+      return "\(entry)"
+    }.joined(separator: ";")
+  }
+}
+
+/// TODO
+public struct TableActions {
+  public init() {}
+}
+
+public struct TablePropertyList: CustomStringConvertible  {
+  let actions: TableActions
+  let keys: TableKeys
+  public init(withActions actions: TableActions, withKeys keys: TableKeys) {
+    self.actions = actions
+    self.keys = keys
+  }
+
+  public var description: String {
+    return "Table Property List: \(self.actions) \(self.keys)"
+  }
+}
+
+public struct Table: CustomStringConvertible  {
+  let properties: TablePropertyList
+  let name: Identifier
+
+  public init(withName name: Identifier, withPropertyList property_list: TablePropertyList) {
+    self.name = name
+    self.properties = property_list
+  }
+
+  public var description: String {
+    return "Table named: \(self.name) \(self.properties)"
+  }
+}
+
+public struct Control: P4Type, P4Value, Equatable, CustomStringConvertible {
+  public static func == (lhs: Control, rhs: Control) -> Bool {
+    // Two "bare" controls are always equal.
+    return true
+  }
+
+  public func eq(rhs: any Common.P4Type) -> Bool {
+    return switch rhs {
+    case is Control: true
+    default: false
+    }
+  }
+
+  public func type() -> any Common.P4Type {
+    return self
+  }
+
+  // Any operation between two "bare" parser states is always true.
+  public func eq(rhs: any Common.P4Value) -> Bool {
+    return switch rhs {
+    case is Control: true
+    default: false
+    }
+  }
+
+  public func lt(rhs: any Common.P4Value) -> Bool {
+    return switch rhs {
+    case is Control: true
+    default: false
+    }
+  }
+
+  public func lte(rhs: any Common.P4Value) -> Bool {
+    return switch rhs {
+    case is Control: true
+    default: false
+    }
+  }
+
+  public func gt(rhs: any Common.P4Value) -> Bool {
+    return switch rhs {
+    case is Control: true
+    default: false
+    }
+  }
+
+  public func gte(rhs: any Common.P4Value) -> Bool {
+    return switch rhs {
+    case is Control: true
+    default: false
+    }
+  }
+
+  public var description: String {
+    return "Control named \(self._name) \(self.parameters) \(self.actions) \(self.table)"
+  }
+
+  let actions: Actions
+  let table: Table
+  let _parameters: ParameterList
+  let _name: Identifier
+
+  public var parameters: ParameterList {
+    get {
+      _parameters
+    }
+  }
+
+  public var name: Identifier {
+    get {
+      _name
+    }
+  }
+
+  public init(named: Identifier, withParameters parameters: ParameterList, withTable table: Table, withActions actions: Actions) {
+    self._name = named
+    self._parameters = parameters
+    self.actions = actions
+    self.table = table
+  }
+
+  public func def() -> any P4Value {
+    return Control(
+      named: Identifier(name: ""),
+      withParameters: ParameterList(),
+      withTable: Table(
+        withName: Identifier(name: "empty"),
+        withPropertyList: TablePropertyList(withActions: TableActions(), withKeys: TableKeys())),
+      withActions: Actions(withActions: []))
+  }
+
+}

Tests/p4rseTests/ControlCompilerTests.swift

@@ -0,0 +1,141 @@
+// 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
+import Foundation
+import Macros
+import Runtime
+import SwiftTreeSitter
+import Testing
+import TreeSitter
+import TreeSitterP4
+import P4Lang
+
+@testable import P4Compiler
+
+@Test func test_simple_control_declaration() async throws {
+  let simple_parser_declaration = """
+    control simple() {
+      action a() {
+      }
+      table t {
+        key = {
+          true: exact;
+        }
+      }
+    };
+    """
+  let x = { (tipe: P4Type) -> Bool in
+    switch tipe {
+    case let c as Control: c.name == "simple"
+    default: false
+    }
+  }
+  let program = try! #UseOkResult(Program.Compile(simple_parser_declaration))
+  #expect(program.InstancesWithTypes(x).count == 1)
+}
+
+@Test func test_simple_control_declaration2() async throws {
+  let simple_parser_declaration = """
+    struct Testing {
+    };
+    control simple() {
+      action a() {
+      }
+      table t {
+        key = {
+          true: exact;
+        }
+      }
+    };
+    control complex() {
+      action b() {
+      }
+      table t {
+        key = {
+          true: exact;
+        }
+      }
+    };
+    """
+
+  let filter = { (tipe: P4Type) -> Bool in
+    switch tipe {
+    case let c as Control: c.name == "simple" || c.name == "complex"
+    default: false
+    }
+  }
+  let program = try! #UseOkResult(Program.Compile(simple_parser_declaration))
+  #expect(program.InstancesWithTypes(filter).count == 2)
+}
+
+@Test func test_simple_control_declaration_with_parameters() async throws {
+  let simple_parser_declaration = """
+    control simple(bool x, bool y) {
+      action a() {
+      }
+      table t {
+        key = {
+          x: exact;
+          y: exact;
+        }
+      }
+    };
+    """
+  #expect(#RequireOkResult(Program.Compile(simple_parser_declaration)))
+}
+
+@Test func test_simple_control_declaration_with_action_using_parameter() async throws {
+  let simple_parser_declaration = """
+    control simple(bool x, bool y) {
+      action a(int z) {
+        z = 5;
+      }
+      table t {
+        key = {
+          x: exact;
+          y: exact;
+        }
+      }
+    };
+    """
+  #expect(#RequireOkResult(Program.Compile(simple_parser_declaration)))
+}
+
+@Test func test_simple_control_declaration_with_action_using_parameter_wrong_type() async throws {
+  let simple_parser_declaration = """
+    control simple(bool x, bool y) {
+      action a(int z) {
+        z = false;
+      }
+      table t {
+        key = {
+          x: exact;
+          y: exact;
+        }
+      }
+    };
+    """
+  #expect(
+    #RequireErrorResult(
+      Error(
+        withMessage:
+          "{51, 20}: Failed to parse a statement element: {57, 10}: Failed to parse a statement element: {57, 1}: Cannot assign value with type Boolean to identifier z with type Int"
+      ),
+      Program.Compile(simple_parser_declaration))
+  )
+}

tree-sitter-p4/grammar.js

@@ -64,7 +64,7 @@ export default grammar({
         instantiation: $ => seq($.typeRef, '(', optional($.parameter_list), ')', $.identifier),
 
         // Declarations
-        declaration: $ => seq(choice($.parserDeclaration, $.parserTypeDeclaration, $.type_declaration, $.function_declaration)),
+        declaration: $ => seq(choice($.parserDeclaration, $.parserTypeDeclaration, $.type_declaration, $.function_declaration, $.control_declaration)),
 
         type_declaration: $=> choice($.struct_declaration),
         struct_declaration: $ => seq($.struct, $.identifier, '{', optional($.struct_declaration_fields), '}'),
@@ -78,6 +78,20 @@ export default grammar({
 
         variableDeclaration: $ => seq(optional($.annotations), $.typeRef, field('variable_name', $.identifier), optional(seq($.assignment, $.expression)), $._semicolon),
 
+        // Control declarations
+        control_declaration: $ => seq($.control, $.identifier, $.parameters, '{', repeat(choice($.table_declaration, $.action_declaration)), '}'),
+        action_declaration: $ => seq($.action, $.identifier, $.parameters, $.statement),
+        table_declaration: $ => seq($.table, $.identifier, '{', optional($.table_property_list), '}'),
+
+        // Table property list
+        table_property_list: $ => repeat1(choice($.table_keys, $.table_actions)),
+        table_keys: $=> seq($.key, '=', '{', repeat($.table_key_entry), '}'),
+        table_key_entry: $=> seq($.keysetExpression, ':', $.table_key_match_type, $._semicolon),
+        table_actions: $=> seq($.actions, '=', '{', optional(repeat1($.identifier)), '}'),
+
+        // match types
+        table_key_match_type: $ => choice($.exact), // support exact only for now.
+
         // Statements
 
         // General statements
@@ -150,6 +164,7 @@ export default grammar({
         enum: $ => "enum",
         error: $ => "error",
         exit: $ => "exit",
+        exact: $ => "exact",
         extern: $ => "extern",
         false: $ => "false",
         header: $ => "header",

tree-sitter-p4/test/corpus/control.txt

@@ -0,0 +1,53 @@
+=========================
+Simple Control Declaration
+=========================
+control simple() {
+  action a() {
+  }
+  table t {
+    key = {
+      x: exact;
+    }
+  }
+};
+
+---
+(p4program
+ (declaration
+  (control_declaration
+   (control)
+   (identifier)
+   (parameters)
+   (action_declaration
+    (action)
+    (identifier)
+    (parameters)
+    (statement
+     (blockStatement)
+    )
+   )
+   (table_declaration
+    (table)
+    (identifier)
+    (table_property_list
+     (table_keys
+      (key)
+      (table_key_entry
+       (keysetExpression
+        (expression
+         (simple_expression
+          (identifier)
+         )
+        )
+       )
+       (table_key_match_type
+        (exact) 
+       )
+      )  
+     )
+    )
+   )
+  )
+ )
+)
+