Improve Parsing of P4 Parsers And Continue Runtime Implementation

1. Parsing of P4 Parsers was broken: Multiple local elements and
statements were not allowed.
2. Support more functionality on scopes.
3. Refactor variable/identifier.
4. Add more tests.

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

Package.swift

@@ -31,8 +31,6 @@ let package = Package(
                 .product(name: "SwiftSyntaxMacros", package: "swift-syntax"),
                 .product(name: "SwiftCompilerPlugin", package: "swift-syntax"),
             ]),
-        // Targets are the basic building blocks of a package, defining a module or a test suite.
-        // Targets can depend on other targets in this package and products from dependencies.
         .target(
             name: "Parser",
             dependencies: [
@@ -52,11 +50,11 @@ let package = Package(
         ),
         .target(
             name: "P4",
-            dependencies: ["P4Macros"]
+            dependencies: ["Macros", "TreeSitterExtensions"]
         ),
         .testTarget(
             name: "ParserTests",
-            dependencies: ["Parser", "P4", "P4Macros"]
+            dependencies: ["Parser", "P4", "Macros", "TreeSitterExtensions"]
         ),
     ]
 )

Sources/P4/Parser.swift

@@ -65,15 +65,13 @@ public struct ParserTransitionStatement: ParserStatement {
 }
 
 public struct VariableDeclarationStatement: ParserStatement {
-    public var id: Identifier
+    public var variable: Variable
-    public init(withIdentifier id: Identifier) {
+    public init(withVariable variable: Variable) {
-        self.id = id
+        self.variable = variable
     }
 
     public func evaluate(execution: ParserExecution) -> ParserExecution {
-        print("Evaluating!")
+        execution.scopes.scopes[0].variables.append(self.variable)
-        execution.scopes.scopes[0].variables.append(Variable(name: id.name, withValue: id.value, isConstant: false))
-        print("Execution: \(execution)")
         return execution
     }
 }

Sources/P4/Program.swift

@@ -15,30 +15,40 @@
 // You should have received a copy of the GNU General Public License
 // along with this program. If not, see <https://www.gnu.org/licenses/>.
 
-public class Identifier: CustomStringConvertible {
+public class Identifier: CustomStringConvertible, Equatable {
     var name: String
-    var value: Value
 
-    public init(name: String, withValue value: Value) {
+    public init(name: String) {
         self.name = name
-        self.value = value
     }
 
     public var description: String {
-        return "\(name) = \(value)"
+        return "\(name)"
+    }
+
+    public static func ==(lhs: Identifier, rhs: Identifier) -> Bool {
+        return lhs.name == rhs.name
     }
 }
 
 public class Variable: Identifier {
     var constant: Bool
+    var value: ValueType
 
-    public init(name: String, withValue value: Value, isConstant constant: Bool) {
+    public init(name: String, withValue value: ValueType, isConstant constant: Bool) {
         self.constant = constant
-        super.init(name: name, withValue: value)
+        self.value = value
+        super.init(name: name)
     }
 
     public override var description: String {
-        return "\(super.description) \(constant ? "(constant)" : "")"
+        return "\(super.description) = \(value) \(constant ? "(constant)" : "")"
+    }
+
+    public var value_type: ValueType {
+        get {
+            value
+        }
     }
 }
 
@@ -49,10 +59,25 @@ public struct Scope: CustomStringConvertible{
     public var description: String {
         var result = String()
         for v in variables {
-            result += "\(v)"
+            result += "\(v)\n"
         }
         return result
     }
+
+    public var count: Int {
+        get {
+            variables.count
+        }
+    }
+
+    public func lookup(identifier: Identifier) -> Variable? {
+        for v in variables {
+            if v == identifier {
+                return v
+            }
+        }
+        return .none
+    }
 }
 
 public struct Scopes: CustomStringConvertible {
@@ -71,11 +96,23 @@ public struct Scopes: CustomStringConvertible {
     public var description: String {
         var result = String()
         for s in scopes {
-            result += "Scope: \(s)\n"
+            result += "Scope:\n\(s)\n"
         }
 
         return result
     }
+
+    public var current: Scope? {
+        get {
+            scopes.last
+        }
+    }
+
+    public var count: Int {
+        get {
+            scopes.count
+        }
+    }
 }
 
 public struct Program {

Sources/P4/Runtime.swift

@@ -41,14 +41,12 @@ public class ParserRuntime: CustomStringConvertible {
         return Result.Ok(P4.ParserRuntime(execution: P4.ParserExecution(start_state)))
     }
 
-    public func run(input: P4.Packet) -> Result<Nothing> {
+    public func run(input: P4.Packet) -> Result<ParserExecution> {
         execution.scopes.enter()
-        print("Execution: \(execution)")
         while execution.state != P4.accept && execution.state != P4.reject {
             execution = execution.state.evaluate(execution: execution)
-            print("Execution: \(execution)")
         }
-        return .Ok(Nothing())
+        return .Ok(execution)
     }
 
     public var description: String {

Sources/P4/Types.swift

@@ -15,15 +15,34 @@
 // You should have received a copy of the GNU General Public License
 // along with this program. If not, see <https://www.gnu.org/licenses/>.
 
-public enum ValueType: CustomStringConvertible {
+public enum ValueType: CustomStringConvertible, Equatable {
     case Boolean(Bool)
+    case Int(Int)
+    case String(String)
 
     public var description: String {
         switch self {
             case ValueType.Boolean(let b):
                 return "\(b) of Boolean"
+            case ValueType.Int(let i):
+                return "\(i) of Int"
+            case ValueType.String(let s):
+                return "\(s) of String"
         }
     }
+
+    public static func==(lhs: ValueType, rhs: ValueType) -> Bool {
+        switch (lhs,rhs) {
+            case (ValueType.Boolean(let lhsb), ValueType.Boolean(let rhsb)):
+                return lhsb == rhsb
+            case (ValueType.String(let lhsb), ValueType.String(let rhsb)):
+                return lhsb == rhsb
+            case (ValueType.Int(let lhsb), ValueType.Int(let rhsb)):
+                return lhsb == rhsb
+            default: return false
+        }
+    }
+
 }
 
 public struct Value: CustomStringConvertible {

Sources/Parser/Parser.swift

@@ -18,284 +18,349 @@
 import P4
 import SwiftTreeSitter
 import TreeSitterP4
-
+import TreeSitterExtensions
-extension MutableTree {
-    public func isError(lang: Language) -> Bool {
-        guard
-            let parser_error_query = try? SwiftTreeSitter.Query(
-                language: lang,
-                data: String(
-                    "(ERROR)"
-                ).data(using: String.Encoding.utf8)!)
-        else {
-            return false
-        }
-
-        let error_qr = parser_error_query.execute(in: self)
-        for _ in error_qr {
-            return true
-        }
-        return false
-    }
-}
 
 let p4lang = Language(tree_sitter_p4())
 
+public protocol ParseableValueType {
+  static func Parse(type: String, withValue value: String) -> Result<P4.ValueType>
+}
+
+// This seems unnecessary because all the value types are in a single enum?
+extension P4.ValueType: ParseableValueType {
+  public static func Parse(type: String, withValue value: String) -> Result<P4.ValueType> {
+    if type == "bool" {
+      // Default
+      if value == "" {
+        return .Ok(P4.ValueType.Boolean(false))
+      }
+
+      if value == "true" {
+        return .Ok(P4.ValueType.Boolean(true))
+      } else if value == "false" {
+        return .Ok(P4.ValueType.Boolean(false))
+      }
+      return .Error(Error(withMessage: "Cannot convert \(value) into boolean value"))
+
+    } else if type == "string" {
+      return .Ok(P4.ValueType.String(value))
+
+    } else if type == "int" {
+      // Default
+      if value == "" {
+        return .Ok(P4.ValueType.Int(0))
+      }
+
+      guard let parsed_value = Swift.Int(value) else {
+        return .Error(Error(withMessage: "Cannot convert \(value) into integer value"))
+      }
+      return .Ok(P4.ValueType.Int(parsed_value))
+    }
+
+    return .Error(Error(withMessage: "Invalid type"))
+  }
+}
+
 public protocol ParseableParserStatement {
-    static func Parse(node: Node, inTree tree: MutableTree) -> Result<P4.ParserStatement?>
+  static func Parse(node: Node, inTree tree: MutableTree) -> Result<P4.ParserStatement?>
 }
 
 extension P4.ExpressionStatement: ParseableParserStatement {
-    public static func Parse(node: Node, inTree tree: MutableTree) -> Result<P4.ParserStatement?> {
+  public static func Parse(node: Node, inTree tree: MutableTree) -> Result<P4.ParserStatement?> {
-        guard
+    guard
-            let parser_state_query = try? SwiftTreeSitter.Query(
+      let parser_state_query = try? SwiftTreeSitter.Query(
-                language: p4lang,
+        language: p4lang,
-                data: String(
+        data: String(
-                    "(expressionStatement (expression) @expression)"
+          "(expressionStatement (expression) @expression)"
-                ).data(using: String.Encoding.utf8)!)
+        ).data(using: String.Encoding.utf8)!)
-        else {
+    else {
-            return Result.Ok(.none)
+      return Result.Ok(.none)
-        }
-
-        let qr = parser_state_query.execute(node: node, in: tree)
-        let query_result = qr.next()!
-        let expression_capture = query_result.captures(named: "expression")
-        if !expression_capture.isEmpty {
-            // TODO: Actually create an ExpressionStatement
-            return Result.Ok(P4.ExpressionStatement())
-        }
-
-        return Result.Ok(.none)
-
     }
+
+    let qr = parser_state_query.execute(node: node, in: tree)
+    let query_result = qr.next()!
+    let expression_capture = query_result.captures(named: "expression")
+    if !expression_capture.isEmpty {
+      // TODO: Actually create an ExpressionStatement
+      return Result.Ok(P4.ExpressionStatement())
+    }
+
+    return Result.Ok(.none)
+
+  }
 }
 
 extension P4.VariableDeclarationStatement: ParseableParserStatement {
-    public static func Parse(node: Node, inTree tree: MutableTree) -> Result<P4.ParserStatement?> {
+  public static func Parse(node: Node, inTree tree: MutableTree) -> Result<P4.ParserStatement?> {
-        guard
+    guard
-            let parser_state_query = try? SwiftTreeSitter.Query(
+      let parser_state_query = try? SwiftTreeSitter.Query(
-                language: p4lang,
+        language: p4lang,
-                data: String(
+        data: String(
-                    "((annotations)? (typeRef) @type-name variable_name: (identifier) @identifier)"
+          "((annotations)? (typeRef) @type-name variable_name: (identifier) @identifier ((assignment) (expression) @value)?)"
-                ).data(using: String.Encoding.utf8)!)
+        ).data(using: String.Encoding.utf8)!)
-        else {
+    else {
-            return Result.Ok(.none)
+      return Result.Ok(.none)
-        }
-
-        let qr = parser_state_query.execute(node: node, in: tree)
-        let parser_declaration = qr.next()!
-
-        let type_name_capture = parser_declaration.captures(named: "type-name")
-        let variable_name_capture = parser_declaration.captures(named: "identifier")
-
-        // There must be a state name and there must be a transition statement.
-        guard !type_name_capture.isEmpty,
-            !variable_name_capture.isEmpty,
-            let variable_name = variable_name_capture[0].node.text
-        else {
-            return Result.Error(Error(withMessage: "Could not parse a parser declaration"))
-        }
-
-        return Result.Ok(
-            // TODO: Add support for parsing the value.
-            P4.VariableDeclarationStatement(
-                withIdentifier: Identifier(
-                    name: variable_name, withValue: Value(withValue: ValueType.Boolean(true)))))
     }
+
+    let qr = parser_state_query.execute(node: node, in: tree)
+    let parser_declaration = qr.next()!
+
+    let type_name_capture = parser_declaration.captures(named: "type-name")
+    let variable_name_capture = parser_declaration.captures(named: "identifier")
+    let value_capture = parser_declaration.captures(named: "value")
+
+    // There must be a type name and a variable name
+    guard !type_name_capture.isEmpty,
+      !variable_name_capture.isEmpty,
+      let variable_name = variable_name_capture[0].node.text,
+      let type_name = type_name_capture[0].node.text
+    else {
+      return Result.Error(Error(withMessage: "Could not parse a parser declaration"))
+    }
+
+    let value =
+      if !value_capture.isEmpty {
+        value_capture[0].node.text!
+      } else {
+        ""
+      }
+
+    return switch P4.ValueType.Parse(type: type_name, withValue: value) {
+    case Result.Ok(let value_type):
+      Result.Ok(
+        P4.VariableDeclarationStatement(
+          withVariable: Variable(name: variable_name, withValue: value_type, isConstant: false)))
+    case Result.Error(let e):
+      Result.Error(e)
+    }
+  }
 }
 
 public struct Parser {
-    static func ParserLocalElements(capture: [QueryCapture], inTree tree: MutableTree) -> Result<
-        [P4.ParserStatement]
-    > {
-        let localElementsParsers: [ParseableParserStatement.Type] = [
-            P4.VariableDeclarationStatement.self
-        ]
 
-        var localElements: [P4.ParserStatement] = Array()
+  public struct P4Parser {
+    static func LocalElements(
+      node: Node, inTree tree: MutableTree
+    ) -> Result<[P4.ParserStatement]> {
 
-        for raw_le_statement in capture {
+      guard
-            var parsed_le_statement: P4.ParserStatement? = .none
+        let parser_le_statement_query = try? SwiftTreeSitter.Query(
+          language: p4lang,
+          data: String(
+            "(parserLocalElement) @parser-local-element"
+          ).data(using: String.Encoding.utf8)!)
+      else {
+        return Result.Error(Error(withMessage: "Could not compile the tree sitter query"))
+      }
 
-            for le_parser in localElementsParsers {
+      let localElementsParsers: [ParseableParserStatement.Type] = [
-                if case Result.Ok(.some(let parsed)) = le_parser.Parse(node: raw_le_statement.node, inTree: tree) {
+        P4.VariableDeclarationStatement.self
-                    parsed_le_statement = parsed
+      ]
-                    break
-                }
-            }
 
-            if let le_statement = parsed_le_statement {
+      var localElements: [P4.ParserStatement] = Array()
-                localElements.append(le_statement)
+
-            } else {
+      let qr = parser_le_statement_query.execute(node: node, in: tree)
-                // There were no parseable statements.
+      for raw_le_statement in qr {
-                return Result.Error(
+        let raw_le_statement_capture = raw_le_statement.captures(named: "parser-local-element")
-                    Error(withMessage: "Failed to parse a local element: \(raw_le_statement)"))
+        var parsed_le_statement: P4.ParserStatement? = .none
-            }
+
+        for le_parser in localElementsParsers {
+          if case Result.Ok(.some(let parsed)) = le_parser.Parse(
+            node: raw_le_statement_capture[0].node, inTree: tree)
+          {
+            parsed_le_statement = parsed
+            break
+          }
         }
 
-        return Result.Ok(localElements)
+        if let le_statement = parsed_le_statement {
-    }
+          localElements.append(le_statement)
-
+        } else {
-    static func ParserStatements(capture: [QueryCapture], inTree tree: MutableTree) -> Result<
+          // There were no parseable statements.
-        [P4.ParserStatement]
+          return Result.Error(
-    > {
+            Error(withMessage: "Failed to parse a local element: \(raw_le_statement)"))
-        let statementParsers: [ParseableParserStatement.Type] = [
-            P4.ExpressionStatement.self, P4.VariableDeclarationStatement.self,
-        ]
-
-        var statements: [P4.ParserStatement] = Array()
-
-        for raw_statement in capture {
-            var parsed_statement: P4.ParserStatement? = .none
-
-            // Iterate through statement parsers and give each one a chance.
-            for parser in statementParsers {
-                if case Result.Ok(.some(let parsed)) = parser.Parse(node: raw_statement.node, inTree: tree) {
-                    parsed_statement = parsed
-                    break
-                }
-            }
-
-            if let statement = parsed_statement {
-                statements.append(statement)
-            } else {
-                // There were no parseable statements.
-                return Result.Error(
-                    Error(withMessage: "Failed to parse a statement element: \(raw_statement)"))
-            }
         }
-        return Result.Ok(statements)
+      }
+
+      return Result.Ok(localElements)
     }
 
-    static func ParserTransitionStatement(node: Node, inTree tree: MutableTree) -> P4
+    static func Statements(
-        .ParserTransitionStatement?
+      node: Node, inTree tree: MutableTree
+    ) -> Result<[P4.ParserStatement]> {
+
+      guard
+        let parser_statement_query = try? SwiftTreeSitter.Query(
+          language: p4lang,
+          data: String(
+            "(parserStatement) @parser-statement"
+          ).data(using: String.Encoding.utf8)!)
+      else {
+        return Result.Error(Error(withMessage: "Could not compile the tree sitter query"))
+      }
+
+      let statementParsers: [ParseableParserStatement.Type] = [
+        P4.ExpressionStatement.self, P4.VariableDeclarationStatement.self,
+      ]
+
+      var statements: [P4.ParserStatement] = Array()
+
+      let qr = parser_statement_query.execute(node: node, in: tree)
+      for raw_statement in qr {
+        let raw_statement_capture = raw_statement.captures(named: "parser-statement")
+
+        var parsed_statement: P4.ParserStatement? = .none
+
+        // Iterate through statement parsers and give each one a chance.
+        for parser in statementParsers {
+          if case Result.Ok(.some(let parsed)) = parser.Parse(
+            node: raw_statement_capture[0].node, inTree: tree)
+          {
+            parsed_statement = parsed
+            break
+          }
+        }
+
+        if let statement = parsed_statement {
+          statements.append(statement)
+        } else {
+          // There were no parseable statements.
+          return Result.Error(
+            Error(withMessage: "Failed to parse a statement element: \(raw_statement)"))
+        }
+      }
+      return Result.Ok(statements)
+    }
+
+    static func TransitionStatement(
+      node: Node, inTree tree: MutableTree
+    ) -> P4.ParserTransitionStatement?
     {
-        return P4.ParserTransitionStatement()
+      return P4.ParserTransitionStatement()
     }
 
-    static func ParserState(node: Node, inTree tree: MutableTree) -> Result<P4.ParserState> {
+    static func State(node: Node, inTree tree: MutableTree) -> Result<P4.ParserState> {
-        guard
+      guard
-            let parser_state_query = try? SwiftTreeSitter.Query(
+        let parser_state_query = try? SwiftTreeSitter.Query(
-                language: p4lang,
+          language: p4lang,
-                data: String(
+          data: String(
-                    "(parserState (state) (identifier) @state-name (parserLocalElements)? @state-local-elements (parserStatements)? @state-statements (parserTransitionStatement) @transition)"
+            "(parserState (state) (identifier) @state-name (parserLocalElements)? @state-local-elements (parserStatements)? @state-statements (parserTransitionStatement) @transition)"
-                ).data(using: String.Encoding.utf8)!)
+          ).data(using: String.Encoding.utf8)!)
-        else {
+      else {
-            return Result.Error(Error(withMessage: "Could not compile the tree sitter query"))
+        return Result.Error(Error(withMessage: "Could not compile the tree sitter query"))
+      }
+
+      let qr = parser_state_query.execute(node: node, in: tree)
+
+      let parser_declaration = qr.next()!
+
+      let transition_capture = parser_declaration.captures(named: "transition")
+      let state_name_capture = parser_declaration.captures(named: "state-name")
+      let state_le_capture = parser_declaration.captures(named: "state-local-elements")
+      let statements_capture = parser_declaration.captures(named: "state-statements")
+
+      // There must be a state name and there must be a transition statement.
+      guard !state_name_capture.isEmpty,
+        !transition_capture.isEmpty,
+        let parsed_state_name = state_name_capture[0].node.text,
+        let transition_statement = TransitionStatement(
+          node: transition_capture[0].node, inTree: tree)
+      else {
+        return Result.Error(Error(withMessage: "Could not parse a parser declaration"))
+      }
+
+      let maybe_parsed_les =
+        if !state_le_capture.isEmpty {
+          LocalElements(node: state_le_capture[0].node, inTree: tree)
+        } else {
+          Result.Ok([P4.ParserStatement]())
         }
 
-        let qr = parser_state_query.execute(node: node, in: tree)
+      guard case Result<[P4.ParserStatement]>.Ok(let parsed_les) = maybe_parsed_les else {
+        return Result.Error(maybe_parsed_les.error()!)
+      }
 
-        let parser_declaration = qr.next()!
+      let maybe_parsed_statements =
-
+        if !statements_capture.isEmpty {
-        let transition_capture = parser_declaration.captures(named: "transition")
+          Statements(node: statements_capture[0].node, inTree: tree)
-        let state_name_capture = parser_declaration.captures(named: "state-name")
+        } else {
-        let state_le_capture = parser_declaration.captures(named: "state-local-elements")
+          Result.Ok([P4.ParserStatement]())
-        let statements_capture = parser_declaration.captures(named: "state-statements")
-
-        // There must be a state name and there must be a transition statement.
-        guard !state_name_capture.isEmpty,
-            !transition_capture.isEmpty,
-            let parsed_state_name = state_name_capture[0].node.text,
-            let transition_statement = ParserTransitionStatement(
-                node: transition_capture[0].node, inTree: tree)
-        else {
-            return Result.Error(Error(withMessage: "Could not parse a parser declaration"))
         }
+      guard case Result<[P4.ParserStatement]>.Ok(let parsed_statements) = maybe_parsed_statements
+      else {
+        return Result.Error(maybe_parsed_statements.error()!)
+      }
 
-        let maybe_parsed_les =
+      // TODO: Validate that there is only one!
-            if !state_le_capture.isEmpty {
+      return Result.Ok(
-                ParserLocalElements(capture: state_le_capture, inTree: tree)
+        P4.ParserState(
-            } else {
+          name: parsed_state_name, withLocalElements: parsed_les,
-                Result.Ok([P4.ParserStatement]())
+          withStatements: parsed_statements,
-            }
+          withTransition: transition_statement))
-
+    }
-        guard case Result<[P4.ParserStatement]>.Ok(let parsed_les) = maybe_parsed_les else {
+  }
-            return Result.Error(maybe_parsed_les.error()!)
+  static func Parser(node: Node, inTree tree: MutableTree) -> Result<P4.Parser> {
-        }
+    guard
-
+      let parser_state_query = try? SwiftTreeSitter.Query(
-        let maybe_parsed_statements =
+        language: p4lang,
-            if !statements_capture.isEmpty {
+        data: String(
-                ParserStatements(capture: statements_capture, inTree: tree)
+          "(parserStates) @parser-states"
-            } else {
+        ).data(using: String.Encoding.utf8)!)
-                Result.Ok([P4.ParserStatement]())
+    else {
-            }
+      return Result.Error(
-        guard case Result<[P4.ParserStatement]>.Ok(let parsed_statements) = maybe_parsed_statements
+        Error(withMessage: "Could not compile the parser state tree sitter query"))
-        else {
-            return Result.Error(maybe_parsed_statements.error()!)
-        }
-
-        // TODO: Validate that there is only one!
-        return Result.Ok(
-            P4.ParserState(
-                name: parsed_state_name, withLocalElements: parsed_les,
-                withStatements: parsed_statements,
-                withTransition: transition_statement))
     }
 
-    static func Parser(node: Node, inTree tree: MutableTree) -> Result<P4.Parser> {
+    var parser = P4.Parser()
-        guard
-            let parser_state_query = try? SwiftTreeSitter.Query(
-                language: p4lang,
-                data: String(
-                    "(parserStates) @parser-states"
-                ).data(using: String.Encoding.utf8)!)
-        else {
-            return Result.Error(
-                Error(withMessage: "Could not compile the parser state tree sitter query"))
-        }
 
-        var parser = P4.Parser()
+    // Build a state from each one listed.
+    for parser_states in parser_state_query.execute(node: node, in: tree) {
+      switch P4Parser.State(node: parser_states.nodes[0], inTree: tree) {
+      case Result.Ok(let state): parser.states.append(state)
+      case Result.Error(let error): return Result.Error(error)
+      }
+    }
+    return Result.Ok(parser)
+  }
 
-        // Build a state from each one listed.
+  public static func Program(_ source: String) -> Result<P4.Program> {
-        for parser_states in parser_state_query.execute(node: node, in: tree) {
+    let p = SwiftTreeSitter.Parser.init()
-            switch ParserState(node: parser_states.nodes[0], inTree: tree) {
+
-            case Result.Ok(let state): parser.states.append(state)
+    do {
-            case Result.Error(let error): return Result.Error(error)
+      try p.setLanguage(p4lang)
-            }
+    } catch {
-        }
+      return Result.Error(Error(withMessage: "Could not configure the P4 parser"))
-        return Result.Ok(parser)
     }
 
-    public static func Program(_ source: String) -> Result<P4.Program> {
+    let result = p.parse(source)
-
+    guard let tree = result,
-        let p = SwiftTreeSitter.Parser.init()
+      !tree.isError(lang: p4lang)
-
+    else {
-        do {
+      return Result.Error(Error(withMessage: "Could not compile the P4 program"))
-            try p.setLanguage(p4lang)
-        } catch {
-            return Result.Error(Error(withMessage: "Could not configure the P4 parser"))
-        }
-
-        let result = p.parse(source)
-        guard let tree = result,
-            !tree.isError(lang: p4lang)
-        else {
-            return Result.Error(Error(withMessage: "Could not compile the P4 program"))
-        }
-
-        guard
-            let parser_declaration_query = try? SwiftTreeSitter.Query(
-                language: p4lang,
-                data: String(
-                    "(parserDeclaration (parserType) (parserStates) @parser-states)"
-                ).data(using: String.Encoding.utf8)!)
-        else {
-            return Result.Error(
-                Error(withMessage: "Could not compile the parser declaration tree sitter query"))
-        }
-
-        var program: P4.Program = P4.Program()
-
-        let parser_qc = parser_declaration_query.execute(in: tree)
-
-        for parser_declaration in parser_qc {
-            switch Parser(node: parser_declaration.nodes[0], inTree: tree) {
-            case Result.Ok(let parser): program.parsers.append(parser)
-            case Result.Error(let error): return Result.Error(error)
-            }
-        }
-
-        return Result.Ok(program)
     }
+
+    guard
+      let parser_declaration_query = try? SwiftTreeSitter.Query(
+        language: p4lang,
+        data: String(
+          "(parserDeclaration (parserType) (parserStates) @parser-states)"
+        ).data(using: String.Encoding.utf8)!)
+    else {
+      return Result.Error(
+        Error(withMessage: "Could not compile the parser declaration tree sitter query"))
+    }
+
+    var program: P4.Program = P4.Program()
+
+    let parser_qc = parser_declaration_query.execute(in: tree)
+
+    for parser_declaration in parser_qc {
+      switch Parser(node: parser_declaration.nodes[0], inTree: tree) {
+      case Result.Ok(let parser): program.parsers.append(parser)
+      case Result.Error(let error): return Result.Error(error)
+      }
+    }
+
+    return Result.Ok(program)
+  }
 }

Tests/p4lmTests/ParserTests.swift

@@ -22,7 +22,7 @@ import TreeSitterP4
 import Foundation
 import P4
 
-import P4Macros
+import Macros
 
 @testable import Parser
 

Tests/p4lmTests/RuntimeTests.swift

@@ -17,7 +17,7 @@
 
 import Foundation
 import P4
-import P4Macros
+import Macros
 import SwiftTreeSitter
 import Testing
 import TreeSitter
@@ -56,27 +56,41 @@ import TreeSitterP4
             P4.ParserRuntime.create(program: program.parsers[0])))
 }
 
-@Test func test_simple_runtime_output() async throws {
+@Test func test_simple_local_element_variable_declaration() async throws {
     let simple_parser_declaration = """
         parser simple() {
            state start {
-               bool b = true;
+               bool b = false;
+               string s = "testing";
+               true;
+               false;
                transition reject;
            }
         }
         """
 
-    /*
-    TODO: Add tests for "semantic" parsing failures. Here's an example!
-    print(Parser.Program(simple_parser_declaration))
-    #expect(
-        #RequireErrorResult(
-            Error(
-                withMessage:
-                    "Failed to parse a local element: <capture 1 \"state-local-elements\": <parserLocalElements range: {42, 14} childCount: 2>>"
-            ), Parser.Program(simple_parser_declaration)))
-    */
     let program = try #UseOkResult(Parser.Program(simple_parser_declaration))
     let runtime = try #UseOkResult(P4.ParserRuntime.create(program: program.parsers[0]))
-    #expect(runtime.run(input: P4.Packet()) == P4.Result.Ok(Nothing()))
+
+    // This seems awkward to me!
+    // TODO: Is there a better way?
+    guard case P4.Result.Ok(let execution_result) = runtime.run(input: P4.Packet()) else {
+        assert(false)
+    }
+
+    // There should be 1 scope.
+    #expect(execution_result.scopes.count == 1)
+
+    guard let scope = execution_result.scopes.current else {
+        assert(false)
+    }
+
+    // There are two variables declared.
+    #expect(scope.count == 2)
+
+    // Check the names/values of the variables in scope.
+    let b = try #require(scope.lookup(identifier: Identifier(name: "b")))
+    let s = try #require(scope.lookup(identifier: Identifier(name: "s")))
+    #expect(b.value_type == ValueType.Boolean(false))
+    #expect(s.value_type == ValueType.String("\"testing\""))
 }