From 2aae03185b17444505618468b9bf27f3e0435fa8 Mon Sep 17 00:00:00 2001
From: "Edward A. Lee" <eal@berkeley.edu>
Date: Tue, 31 Dec 2024 10:45:45 -0800
Subject: [PATCH 1/2] Allow derived classes to override parameter default
 values

---
 .../lflang/generator/c/CParameterGenerator.java   |  9 +++++++++
 test/C/src/ParameterOverride.lf                   | 15 +++++++++++++++
 2 files changed, 24 insertions(+)
 create mode 100644 test/C/src/ParameterOverride.lf

diff --git a/core/src/main/java/org/lflang/generator/c/CParameterGenerator.java b/core/src/main/java/org/lflang/generator/c/CParameterGenerator.java
index 273f058d57..f73f3aefb5 100644
--- a/core/src/main/java/org/lflang/generator/c/CParameterGenerator.java
+++ b/core/src/main/java/org/lflang/generator/c/CParameterGenerator.java
@@ -6,6 +6,8 @@
 import org.lflang.lf.Initializer;
 import org.lflang.lf.Parameter;
 
+import java.util.HashSet;
+
 /**
  * Generates C code to declare and initialize parameters.
  *
@@ -41,7 +43,14 @@ public static String getInitializer(ParameterInstance p) {
   public static String generateDeclarations(
       TypeParameterizedReactor reactor, CTypes types, boolean suppressLineDirectives) {
     CodeBuilder code = new CodeBuilder();
+    // Allow derived classes to override base class parameter definitions.
+    // Assume that the validator has checked that types match.
+    var declared = new HashSet<String>();
     for (Parameter parameter : ASTUtils.allParameters(reactor.reactor())) {
+      // If the parameter name has been seen already, assume it is an override of the default value
+      // in a derived class.  The validator should check.
+      if (declared.contains(parameter.getName())) continue;
+      declared.add(parameter.getName());
       code.prSourceLineNumber(parameter, suppressLineDirectives);
       code.pr(
           types.getTargetType(reactor.resolveType(ASTUtils.getInferredType(parameter)))
diff --git a/test/C/src/ParameterOverride.lf b/test/C/src/ParameterOverride.lf
new file mode 100644
index 0000000000..d639eea3af
--- /dev/null
+++ b/test/C/src/ParameterOverride.lf
@@ -0,0 +1,15 @@
+target C
+
+reactor A(x:int = 0) {
+  reaction(startup) {=
+    if (self->x != 1) {
+      lf_print_error_and_exit("x is %d. Should be 1.", self->x);
+    }
+  =}
+}
+
+reactor B(x:int = 1) extends A { }
+
+main reactor {
+  b = new B()
+}

From 9c8a6f00fe09b5257ad3446d0126eb63fa9c59f9 Mon Sep 17 00:00:00 2001
From: "Edward A. Lee" <eal@berkeley.edu>
Date: Tue, 31 Dec 2024 11:10:29 -0800
Subject: [PATCH 2/2] Spotless

---
 .../java/org/lflang/generator/c/CParameterGenerator.java     | 3 +--
 test/C/src/ParameterOverride.lf                              | 5 +++--
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/core/src/main/java/org/lflang/generator/c/CParameterGenerator.java b/core/src/main/java/org/lflang/generator/c/CParameterGenerator.java
index f73f3aefb5..bcf03ea33a 100644
--- a/core/src/main/java/org/lflang/generator/c/CParameterGenerator.java
+++ b/core/src/main/java/org/lflang/generator/c/CParameterGenerator.java
@@ -1,13 +1,12 @@
 package org.lflang.generator.c;
 
+import java.util.HashSet;
 import org.lflang.ast.ASTUtils;
 import org.lflang.generator.CodeBuilder;
 import org.lflang.generator.ParameterInstance;
 import org.lflang.lf.Initializer;
 import org.lflang.lf.Parameter;
 
-import java.util.HashSet;
-
 /**
  * Generates C code to declare and initialize parameters.
  *
diff --git a/test/C/src/ParameterOverride.lf b/test/C/src/ParameterOverride.lf
index d639eea3af..b586281dee 100644
--- a/test/C/src/ParameterOverride.lf
+++ b/test/C/src/ParameterOverride.lf
@@ -1,6 +1,6 @@
 target C
 
-reactor A(x:int = 0) {
+reactor A(x: int = 0) {
   reaction(startup) {=
     if (self->x != 1) {
       lf_print_error_and_exit("x is %d. Should be 1.", self->x);
@@ -8,7 +8,8 @@ reactor A(x:int = 0) {
   =}
 }
 
-reactor B(x:int = 1) extends A { }
+reactor B(x: int = 1) extends A {
+}
 
 main reactor {
   b = new B()