(finder:get-file directory prompt filter filter-msg parent) -> (union string #f)
directory = #f : (union string #f)
prompt = "Select File" : string
filter = #f : (union regexp #f)
filter-msg = "That filename does not have the right form." : string
parent = (finder:dialog-parent-parameter) : (union (instance top-level-window<%>) #f)
If the result of (preferences:get 'framework:file-dialogs)
is 'std this calls
finder:std-get-file, and if it is 'common,
finder:common-get-file is called.