From 99ee0da8c12b449ed1e12128e64c7fe29b857680 Mon Sep 17 00:00:00 2001
From: Dustin Swan <dustin@dustinswan.com>
Date: Mon, 6 Apr 2026 19:54:16 -0600
Subject: [PATCH] Adding applyModule! function

---
 src/runtime-js.ts | 40 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 40 insertions(+)

diff --git a/src/runtime-js.ts b/src/runtime-js.ts
index 94bd6c4..6f0c505 100644
--- a/src/runtime-js.ts
+++ b/src/runtime-js.ts
@@ -169,6 +169,46 @@ export const _rt = {
             });
        }
     },
+    "applyModule!": (moduleName: string) => (code: string) => {
+        try {
+            const tokens = tokenize(code);
+            const parser = new Parser(tokens, code);
+            const { definitions: defs } = parser.parse();
+
+            // Find existing module defs
+            const existingNames = new Set(
+                [...definitions.values()]
+                    .filter(d => d.module === moduleName)
+                    .map(d => d.name)
+            );
+
+            // Apply new defs
+            const newNames = new Set<string>();
+            for (const def of defs) {
+                def.module = moduleName;
+                if (def.body) {
+                    recompile(def.name, def.body);
+                    definitions.set(def.name, def);
+                    newNames.add(def.name);
+                }
+            }
+
+            // Delete missing defs
+            for (const name of existingNames) {
+                if (!newNames.has(name)) {
+                    delete store[name];
+                    definitions.delete(name);
+                }
+            }
+
+            // Sync to disk
+            syncToFilesystem([...newNames][0] || moduleName);
+
+            return { _tag: 'Defined', _0: moduleName };
+        } catch (e: any) {
+            return { _tag: 'Err', _0: e.message };
+        }
+    },
     "saveModule!": (moduleName: string) => {
         const moduleDefs = [...definitions.values()]
             .filter(d => d.module === moduleName);