TIP: 106
Title: Add Encoding Abilities to the [dde] Command
Version: $Revision: 1.6 $
Author: Harald Oehlmann <[email protected]>
State: Draft
Type: Project
Vote: Pending
Created: 13-Aug-2002
Post-History:
Tcl-Version: 8.6
~ Abstract
When using Windows DDE communication with non-Tcl programs, the
encoding of the exchanged strings is mostly needed to be the system
encoding. Selection of this behaviour should be possible with in the
[[dde]] command should be done by a parameter.
~ Specification
Extend the [[dde]] command by the option ''-encoding''. For example:
| dde -encoding system execute CS CS {[Set(Var,"�pfel"]}
The default value for the encoding is ''utf-8'' for backward
compatibility.
~ Rationale
The communication with DDE with external programs uses the format
clipboard ''CF_TEXT'' and the sent text should be coded in the system
encoding (''cp1252'' in my locale).
Most people who use DDE to communicate with, for example, Excel use
the fact that what Excel expects (''cp1252'') and what Tcl actually
sends (''utf-8'') is identical for 7-bit values and they don't use
8-bit values. Unfortunately, characters needed in German, French and
other languages are located over this limit and thus are not
transferable.
Peter Hardie addressed this point on 2000-10-26 in the Tcl Feature
Request at SourceForge (#219185: "dde only handles UTF-8 data (-binary
patch available)"
[http://sf.net/tracker/?func=detail&aid=219185&group_id=10894&atid=360894]).
His proposal was to add a ''-binary'' option. I think that an
''-encoding'' option is more general purpose and needs only very
little supplementary coding.
It is envisaged that the main needed encodings will be:
utf-8: For Tcl-to-Tcl communication.
system: For the communication with other programs.
binary: To fully control the sent data.
~ Reference Implementation
May be done after discussion.
~ Copyright
This document has been placed in the public domain