Add macro guard to generated C header files

1 files changed, 12 insertions, 1 deletions

diff --git a/src/main/java/org/shedlang/compiler/backends/PatioNativeCHeadersBackend.java b/src/main/java/org/shedlang/compiler/backends/PatioNativeCHeadersBackend.java
index e483708b..caa84cfc 100644
--- a/src/main/java/org/shedlang/compiler/backends/PatioNativeCHeadersBackend.java
+++ b/src/main/java/org/shedlang/compiler/backends/PatioNativeCHeadersBackend.java
@@ -54,8 +54,13 @@ public class PatioNativeCHeadersBackend implements Backend {
             NamespaceName namespaceName,
             PatioCompilationUnit patioCompilationUnit
         ) throws IOException, InterruptedException {
+            var macroName = String.format(
+                "SHED_NAMESPACES__%s__H",
+                String.join("__", namespaceName.parts())
+            );
             serializeToDisk(
                 targetDir.namespace(namespaceName),
+                macroName,
                 patioCompilationUnit
             );
 
@@ -69,21 +74,26 @@ public class PatioNativeCHeadersBackend implements Backend {
             String mainFunctionName,
             ProfileConfig profileConfig
         ) throws IOException, InterruptedException {
+            var macroName = String.format("SHED_BINS__%s__H", binName);
             serializeToDisk(
                 targetDir.bin(binName),
+                macroName,
                 patioCompilationUnit
             );
         }
 
         private void serializeToDisk(
             PartialTargetPath partialTargetPath,
+            String macroName,
             PatioCompilationUnit patioCompilationUnit
         ) throws IOException {
             var empty = true;
 
             var builder = new StringBuilder();
             // TODO: path to header file? Use angle brackets?
-            builder.append("#include \"shed.h\"\n");
+            builder.append(String.format("#ifndef %s\n", macroName));
+            builder.append(String.format("#define %s\n\n", macroName));
+            builder.append("#include \"shed.h\"\n\n");
             for (var element : patioCompilationUnit.elements()) {
                 if (element instanceof PatioFunctionDeclaration patioFunctionDeclaration) {
                     // TODO: pass this information through rather than having to inspect the string?
@@ -101,6 +111,7 @@ public class PatioNativeCHeadersBackend implements Backend {
                     }
                 }
             }
+            builder.append("\n#endif\n");
 
             if (empty) {
                 return;