# File dialog functions

These functions present dialog boxes for requesting new and old files according to platform conventions.

`request_old_file(`[`prompt` `=` string] [`,` `default_dir` `=` DirRef]`)`
  Prompts the user for an existing file. Returns a FileRef object, or `None` if the user cancelled.

`request_new_file(`[`prompt` `=` string] [`,` `default_dir` `=` DirRef] [`,` `default_name` `=` string]`)`
  Prompts the user for a new file. Returns a FileRef object, or `None` if the user cancelled.