REPL: Set program text (#317)

* adding function set_program_text

* adding function set_program_text

src/bundles/repl/functions.ts

@@ -102,6 +102,16 @@ export function set_font_size(font_size_px: number) {
   INSTANCE.customizedEditorProps.fontSize = parseInt(font_size_px.toString());// The TypeScript type checker will throw an error as "parseInt" in TypeScript only accepts one string as parameter.
 }
 
+/**
+ * Set program text in the Repl editor to the given string
+ * @param {text} string
+ *
+ * @category Main
+ */
+export function set_program_text(text: string) {
+  INSTANCE.updateUserCode(text);
+}
+
 /**
  * When use this function as the entrance function in the parameter of "set_evaluator", the Programmable Repl will directly use the default js-slang interpreter to run your program in Programmable Repl editor. Do not directly call this function in your own code.
  * @param {program} Do not directly set this parameter in your code.

src/bundles/repl/index.ts

@@ -42,5 +42,6 @@ export {
   repl_display,
   set_background_image,
   set_font_size,
+  set_program_text,
   default_js_slang
 } from './functions';