[Modeling] Re: Seq. diag. answer to Michael Winikoff
Tue, 25 Mar 2003 16:49:50 +1100
On Mon, Mar 24, 2003 at 12:17:37PM +0100, Radovan Cervenka wrote:
> Dear all,
> I do no think that symbols like ?, !, ||, etc. are more understandable than
> alt, brk, par, etc. They are maybe better readable, ... but reader/writer
> needs to know exact semantics anyhow. I think that original intention of UML
> 2.0 developers, when they proposed using of textual shortcuts, was to give a
> hint about the semantics to English speaking users.
> But why to use another notation for standardized modeling elements?
> Alternative notations with exactly the same semantics can confuse users. Do
> not you think that it would make (small) problems with compatibility,
> usability and understandability of the language. Imagine joining of
> models/diagrams built by several groups of analysts, and each group used
> different notation.
Briefly, I believe that some sort of suggestive icon is a lot easier to read and
process than a three letter acronym (especially for casual users of the notation
- "what does ign mean again?")
Regarding multiple notations, any half-decent tool should be able to
automatically switch presentations, i.e. show "alt" as "?" (or whatever symbol
is chosen) so I don't see this as a significant issue.
Ideally, I'd argue for REPLACING the three letter acronyms with symbols/icons,
however it is too late for this, so I'm just suggesting that we define and
permit an alternative presentation. I believe that this will AID the readability
and understandability of the notation. I appreciate your concerns over different
notations, but in this case the difference is very small and, more importantly,
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> ----- Original Message -----
> From: "James Odell" <firstname.lastname@example.org>
> To: <email@example.com>
> Sent: Sunday, March 23, 2003 2:52 PM
> Subject: [Modeling] Re: Seq. diag. answer to Michael Winikoff
> > Ooops, I forgot to answer this item:
> > >Page 12: "the abbreviations are alt, brk ..." These are not at all easy
> to read
> > >and understand. I'd like to suggest that we allow graphical/mnemonic
> > >alternatives. How about these as a first suggestion:
> > >alt = ? or diamond
> > >brk = ! or stop symbol
> > >par = || or an arrow to a thick horizontal bar with two arrows coming out
> of it
> > >neg = - or x or a logical negation symbol (probably not the latter)
> > >ign = . (can't think of a good symbol for this - a cross over a human ear
> > >getting too complex ... :-)
> > >loop = little loop symbol (or @ if using ASCII?)
> > >
> > >Answer: I think Jim has the answer but I think it is not possible to use
> > >graphical symbol since I am rather doubt that UML 2 CombinedFragment
> > >graphical symbol, Jim, do you have an answer?
> > What we could do is extend UML by offering both options. That way it
> > be backward and forward compatible. We do need to be concerned about
> > symbols that are too specialized. I think the ones that Michael proposes
> > should be OK. It's the upsidedown "A" and backward "E" type of thing we
> > need to avoid.
> Modeling mailing list
Michael Winikoff, Senior Lecturer
School of Computer Science and Information Technology