build it

.gitignore

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+examples/*
+!*.gen.ts
+!*.gen.js

README.md

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 # codegen
 
+Use:
+
+```sh
+deno run --allow-read --allow-write src/codegen.ts
+```

deno.json

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+{
+	"compilerOptions": {
+		"lib": ["deno.ns", "DOM"],
+		"strict": true
+	},
+	"include": ["src"],
+	"tasks": {},
+	"imports": {},
+	"fmt": {
+		"useTabs": true
+	}
+}

deno.lock

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+{
+  "version": "4",
+  "specifiers": {
+    "jsr:@std/fs@*": "1.0.6",
+    "jsr:@std/path@*": "1.0.8",
+    "jsr:@std/path@^1.0.8": "1.0.8"
+  },
+  "jsr": {
+    "@std/fs@1.0.6": {
+      "integrity": "42b56e1e41b75583a21d5a37f6a6a27de9f510bcd36c0c85791d685ca0b85fa2",
+      "dependencies": [
+        "jsr:@std/path@^1.0.8"
+      ]
+    },
+    "@std/path@1.0.8": {
+      "integrity": "548fa456bb6a04d3c1a1e7477986b6cffbce95102d0bb447c67c4ee70e0364be"
+    }
+  }
+}

examples/sample.gen.ts

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+export default () => {
+	return `console.log("Hello, World!");`;
+};

examples/somethingEarly.gen.ts

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+export default () => {
+	return `export const five = 5;`;
+};

examples/somethingLate.gen.ts

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+export default async (context: any) => {
+	const { five } = await context.import("./somethingEarly.ts");
+	return five.toString();
+};

src/codegen.ts

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+import * as path from "jsr:@std/path";
+
+const root = Deno.cwd();
+
+const getAllFiles = async (dir: string) => {
+	const localEntries = await Array.fromAsync(Deno.readDir(dir));
+	const entries = localEntries.filter((e) => e.isFile).map((e) => e.name);
+	for (const entry of localEntries) {
+		if (
+			entry.isDirectory &&
+			!entry.isSymlink &&
+			!entry.name.startsWith(".")
+		) {
+			entries.push(
+				...(await getAllFiles(entry.name)).map((fname) =>
+					path.join(entry.name, fname)
+				)
+			);
+		}
+	}
+	return entries;
+};
+
+const getFilesToGenFrom = async () => {
+	const allFiles = await getAllFiles(root);
+	return allFiles
+		.filter(
+			(fname) => fname.endsWith(".gen.ts") || fname.endsWith(".gen.js")
+		)
+		.map((fname) => path.join(root, fname));
+};
+
+const filesBeingGenned: Record<string, Promise<void>> = {};
+
+const genFromFile = async (fname: string) => {
+	const context = {
+		async import(moduleName: string) {
+			const fullname = path.resolve(path.dirname(fname), moduleName);
+			await filesBeingGenned[fullname];
+			return import(fullname);
+		},
+	};
+	type CodegenContext = typeof context;
+	const brain: (context: CodegenContext) => string | Promise<string> = (
+		await import(fname)
+	).default;
+	const fileToWrite = fname.replace(/\.gen\.[tj]sx?$/, (ext) =>
+		ext.slice(".gen".length)
+	);
+	Deno.writeTextFile(fileToWrite, await brain(context));
+};
+
+for (const file of await getFilesToGenFrom()) {
+	filesBeingGenned[file] = genFromFile(file);
+}