diff --git a/cli/asc.js b/cli/asc.js
index 7a5cfa62ba..98335e8290 100644
--- a/cli/asc.js
+++ b/cli/asc.js
@@ -223,7 +223,9 @@ exports.main = function main(argv, options, callback) {
           baseDir: { value: baseDir },
           readFile: { value: readFile },
           writeFile: { value: writeFile },
-          listFiles: { value: listFiles }
+          listFiles: { value: listFiles },
+          log: { value: writeStdout },
+          error: { value: (str) => stderr.write(str)}
         });
         transforms.push(new classOrModule());
       } else {
diff --git a/cli/transform.d.ts b/cli/transform.d.ts
index 82085bf878..0d7c5ab294 100644
--- a/cli/transform.d.ts
+++ b/cli/transform.d.ts
@@ -19,6 +19,12 @@ export abstract class Transform {
   /** Lists all files in a directory. */
   listFiles(dirname: string, baseDir: string): string[] | null;
 
+  /** Prints to stdout */
+  log(s: string): void;
+
+  /** Prints to stderr */
+  error(s: string): void;
+
   /** Called when parsing is complete, before a program is instantiated from the AST. */
   afterParse?(parser: Parser): void;
 }