The Clipboard extension: getting and setting the clipboard

Download Clipboard extension

Here are some routines to read from and set the Windows clipboard. There are two sets of routines that vary in how they treat the contents of the clipboard as well as a routine for waiting for the clipboard to change.

Extended ASCII (aka, Windows-1252)

The first set only handles the Windows character set, not Unicode. The Clipboard.Get() function returns the contents of the Windows clipboard converted to the TEXT clipboard format and the Clipboard.Set(text) procedure sets the clipboard to text. If the clipboard doesn't contain text, Clipboard.Get() returns "" and Clipboard.Get(default) returns default. I believe Unicode characters get turned into ?'s. Sample Vocola commands using these routines:

show clipboard = MsgBoxConfirm('"' Clipboard.Get() '"', 64, 
                               "Current contents of clipboard");

set clipboard to <_anything> = Clipboard.Set($1);

Combining the two routines can do fun things like underscore the current selection (e.g., X Y Z becomes X_Y_Z):

include "string.vch";

underscore that = 
    Clipboard.Set( Replace(Clipboard.Get()," ","_") ) 

(The latest version of string.vch can be found in the Vocola 2 samples directory.) Note that Vocola 2 uses Windows-1252 as its character set because that is what Dragon uses. Thus, you can write Vocola 2 commands like:

set an accent = Clipboard.Set(naïve);

and it will work.


The second set of routines deals with Unicode. In order to encode Unicode so that Vocola 2 can deal with it, these routines convert it to/from UTF-8. UTF-8 (or Unicode) cannot be entered directly in Vocola 2 source code or sent as keyboard input (e.g., directly or via SendDragonKeys or SendSystemKeys). You can, however, use Eval to create UTF-8. For example, you can write:

UTF8(text) := EvalTemplate('u"$text".encode("UTF-8")');

paste Greek Delta    = Clipboard.SetUTF8(UTF8(\u03b4)) {ctrl+v};
paste Greek sentence =
        UTF8("A lowercase Greek delta is written \u03b4"
             " and an uppercase one is written \u0394."))

The input text to UTF8 is in Windows-1252 supplemented with Unicode character specifications of the form \uffff or \Uffffffff where the f's are hexadecimal digits specifying the code point of a Unicode character. You can get the input for UTF8(-) by copying some Unicode text from the web or a program like Word into the clipboard then issuing the following command.

  # this escapes all non-ASCII, using \xFF for Windows-1252 and
  # \uUUUU otherwise
show Unicode clipboard =
       "Current Unicode contents of clipboard");

As a convenience, the routines Clipboard.{Save,Restore}(name) can be used to save and restore the clipboard via the variable clipboard:name (via the Variable extension; name defaults to save if omitted). This saving and restoring is done using Unicode so should leave the clipboard undisturbed if it contains text (as opposed to say an image). We can use these routines to improve our "underscore that" command so that it does not modify the clipboard as a side effect if it contains text:

underscore that = Clipboard.Save() {ctrl+x} 
                  Clipboard.Set( Replace(Clipboard.Get()," ","_") )
                  {ctrl+v} Clipboard.Restore();

Waiting for the clipboard to change

It can be useful when dealing with slow applications (e.g., due to a high latency connection to a remote application) to be able to wait for the clipboard to change. Clipboard.WaitForNew(unlikely[,timeout]) does this, waiting either for the clipboard to change from unlikely or for timeout seconds (defaults to 20 seconds if omitted) to elapse. Its usage typically looks like:

... Clipboard.Set(24578245) {ctrl+c} Clipboard.WaitForNew(24578245)
... Clipboard.Get() ...


The Windows clipboard functionality is fairly temperamental. Occasionally, for reasons I don't understand, getting the clipboard produces an error. Usually, this error stops occurring after a while.