diff --git a/src/index.ts b/src/index.ts
new file mode 100644
index 000000000..031f69fee
--- /dev/null
+++ b/src/index.ts
@@ -0,0 +1,27 @@
+import { SourceFile, TextFile } from "./cst";
+import { Diagnostics, UnexpectedCharDiagnostic, UnexpectedTokenDiagnostic } from "./diagnostics";
+import { ParseError, Parser } from "./parser";
+import { Punctuator, ScanError, Scanner } from "./scanner";
+
+export function parseSourceFile(file: TextFile, diagnostics: Diagnostics): SourceFile | null {
+  const scanner = new Scanner(file.text, 0, diagnostics, file);
+  const punctuated = new Punctuator(scanner);
+  const parser = new Parser(file, punctuated);
+  let sourceFile;
+  try {
+    sourceFile = parser.parseSourceFile();
+  } catch (error) {
+    if (error instanceof ParseError) {
+      diagnostics.add(new UnexpectedTokenDiagnostic(error.file, error.actual, error.expected));
+      return null;
+    }
+    if (error instanceof ScanError) {
+      diagnostics.add(new UnexpectedCharDiagnostic(error.file, error.position, error.actual));
+      return null;
+    }
+    throw error;
+  }
+  sourceFile.setParents();
+  return sourceFile;
+}
+