Support Function Calls

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

Tests/p4rseTests/ExpressionTests/FunctionCall.swift

@@ -0,0 +1,136 @@
+// 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 P4Lang
+import P4Runtime
+import SwiftTreeSitter
+import Testing
+import TreeSitter
+import TreeSitterP4
+
+@testable import P4Compiler
+
+@Test func test_function_call_scoped_name_collision() async throws {
+  let simple_parser_declaration = """
+      bool functionb(bool c) {
+        return c;
+      };
+      parser main_parser() {
+        state start {
+          int c = 5;
+          bool b = functionb(true);
+          transition select (b) {
+            false: reject;
+            true: accept;
+          };
+        }
+      };
+    """
+
+  let program = try #UseOkResult(Program.Compile(simple_parser_declaration))
+  let parser = try #UseOkResult(program.find_parser(withName: Identifier(name: "main_parser")))
+  let runtime = try #UseOkResult(P4Runtime.ParserRuntime.create(program: program))
+  let (state_result, _) = try! #UseOkResult(runtime.run())
+
+  #expect(parser.states.count() == 1)
+
+  #expect(AsInstantiatedParserState(state_result) == P4Lang.accept)
+}
+
+@Test func test_function_call_scoped_name_collision2() async throws {
+  // Test whether the assignment to c leaks out of the function call scope.
+  let simple_parser_declaration = """
+      bool functionb(bool c) {
+        c = true;
+        return c;
+      };
+      parser main_parser() {
+        state start {
+          bool c = false;
+          bool b = functionb(true);
+          transition select (c) {
+            false: reject;
+            true: accept;
+          };
+        }
+      };
+    """
+
+  let program = try #UseOkResult(Program.Compile(simple_parser_declaration))
+  let parser = try #UseOkResult(program.find_parser(withName: Identifier(name: "main_parser")))
+  let runtime = try #UseOkResult(P4Runtime.ParserRuntime.create(program: program))
+  let (state_result, _) = try! #UseOkResult(runtime.run())
+
+  #expect(parser.states.count() == 1)
+
+  #expect(AsInstantiatedParserState(state_result) == P4Lang.reject)
+}
+
+@Test func test_function_call_integer_return_value() async throws {
+  let simple_parser_declaration = """
+      int functionb(int c) {
+        return c;
+      };
+      parser main_parser() {
+        state start {
+          int c = 5;
+          transition select (5 == functionb(c)) {
+            false: reject;
+            true: accept;
+          };
+        }
+      };
+    """
+
+  let program = try #UseOkResult(Program.Compile(simple_parser_declaration))
+  let parser = try #UseOkResult(program.find_parser(withName: Identifier(name: "main_parser")))
+  let runtime = try #UseOkResult(P4Runtime.ParserRuntime.create(program: program))
+  let (state_result, _) = try! #UseOkResult(runtime.run())
+
+  #expect(parser.states.count() == 1)
+
+  #expect(AsInstantiatedParserState(state_result) == P4Lang.accept)
+}
+
+@Test func test_function_call_integer_return_value2() async throws {
+  let simple_parser_declaration = """
+      int functionb(int c) {
+        return c;
+      };
+      parser main_parser() {
+        state start {
+          int c = 5;
+          transition select (4 == functionb(c)) {
+            false: reject;
+            true: accept;
+          };
+        }
+      };
+    """
+
+  let program = try #UseOkResult(Program.Compile(simple_parser_declaration))
+  let parser = try #UseOkResult(program.find_parser(withName: Identifier(name: "main_parser")))
+  let runtime = try #UseOkResult(P4Runtime.ParserRuntime.create(program: program))
+  let (state_result, _) = try! #UseOkResult(runtime.run())
+
+  #expect(parser.states.count() == 1)
+
+  #expect(AsInstantiatedParserState(state_result) == P4Lang.reject)
+}

Tests/p4rseTests/ExpressionTests/SelectExpression.swift

@@ -176,7 +176,7 @@ import TreeSitterP4
   let runtime = try #UseOkResult(P4Runtime.ParserRuntime.create(program: program))
 
   let args = ArgumentList([
-    P4BooleanValue(withValue: false), P4StringValue(withValue: "Testing"), P4IntValue(withValue: 5),
+    Argument(P4BooleanValue(withValue: false), atIndex: 1), Argument(P4StringValue(withValue: "Testing"), atIndex: 2), Argument(P4IntValue(withValue: 5), atIndex: 3),
   ])
   let (state_result, _) = try! #UseOkResult(runtime.run(withArguments: args))
   #expect(AsInstantiatedParserState(state_result) == P4Lang.reject)
@@ -197,7 +197,7 @@ import TreeSitterP4
   let runtime = try #UseOkResult(P4Runtime.ParserRuntime.create(program: program))
 
   let args = ArgumentList([
-    P4BooleanValue(withValue: false), P4StringValue(withValue: "Testing"), P4IntValue(withValue: 5),
+    Argument(P4BooleanValue(withValue: false), atIndex: 1), Argument(P4StringValue(withValue: "Testing"), atIndex: 2), Argument(P4IntValue(withValue: 5), atIndex: 3),
   ])
   let (state_result, _) = try! #UseOkResult(runtime.run(withArguments: args))
   #expect(AsInstantiatedParserState(state_result) == P4Lang.accept)