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Mr. Yezierski,
Thanks for the reply. I will have to be brief, because we're at the end
of the school term, and I am on a sleep deficit. I've inserted a few
paragraphs between yours.
[EMAIL PROTECTED] wrote:
>
>[T] Misreading of "No, no, a thousand times no!" is based on use of "no"
> as a logical negation, when that is clearly not the intention of the
> speaker. "No parking" and "no rocket scientist" are examples of
> negation. A linguist would characterize "No!" as an expletive, I think
> -- meaning that they don't know what to do with it when they are
> parsing. Hooting at a linguist also creates numerous academic problems.
>
>[Y] So when someone says "There ain't no parking here", we determine his
> intention based on our evaluation of his level of intelligence. If we
> consider him smart enough to understand the transformation of a negation
> into an expletive, we conclude that he said what he intended to and we
> reinforce our positive evaluation of his intelligence. If we consider him
> too unintelligent to consciously grasp the use of the expletive or to
> understand multiplicative negation, we conclude that he did not "say" what
> he intended to and again reinforce our existing opinion of his
> intelligence. Interestingly, in both cases we interpret his statement as
> saying "parking is not allowed here", so the use of the "rules" is directed
> more at evaluating the person than evaluating the statement.
[T] Being an old hillbilly myself, I try not to judge hillbilly
intelligence on speech patterns. It's not our assessment of the
speaker's intelligence that guides our interpretation of "There ain't no
parking here!" We assess the speaker's intentions, and use that
assessment for cues about how to interpret his words. I think that this
is more general in natural language than is commonly understood.
Language does a great deal more than assert facts and propositions, and
I don't think that common grammar parses other kinds of sentences very
effectively.
>[Y] Here's another mental diversion for you. Why is the concept of the
> expletive so closely tied to the concept of the negative? In the statement
> "There ain't no bleeping parking here", a high percentage of readers would
> classify "bleeping" as an expletive. Yet in the statement "Hooray, I found
> a parking space right in front of the store", many people would be
> comfortable classifying "hooray" as an expletive?
[T] You and I are guessing differently. I think most people would
easily see "hooray" as an expletive.
>[Y] "If human actors can't receive messages when we use sequence diagrams
> during design activities, shouldn't they also be restricted from sending
> them?" -Yezierski. That's stated like a syllogism, but it doesn't
> follow. We are using design tools to reveal what the system must retain
> and do, and a message to an object from an actor implies an operation of
> the object -- a kind of information about the system that we do not get
> from messages *to* the actor. Our biased interest in the system creates
> an asymmetry.
>
> My thought there was triggered by recent experiences trying to do sequence
> diagrams for extensions to Rose I am building in Visual Basic. I wasn't
> truly proposing that human actors be eliminated, but there is a more
> substantial issue here than appears at first glance. First, let me say I
> am speaking in the realm of design rather than requirements, so part of the
> resolution may be that depictions in the two realms need not be consistent.
>
> In Visual Basic, the standard user interface events are private; therefore
> when an actor is portrayed in a sequence diagram as interacting with a user
> interface, the message sent by the actor cannot be linked to the private
> operation/event implemented by the user interface. The correspondence
> between user action and user interface event is lost. So the question now
> becomes how to portray it. One option is to send a message from the actor
> to the user interface worded something like "user pushes button X".
> Another option is to put a note in the diagram saying the same thing and
> linking the note to the private message send that takes place in the user
> interface. [Let me say here that I am not a proponent of removing human
> actors from design documentation, but I do think the asymmetry you refer to
> adds its own set of issues to the development process. I would agree with
> Mr. Oldfield 's statement that the correspondence between operations and
> messages is not a necessary condition, but at times I do wonder about the
> use of human actors in design level diagrams.]
>
> If I choose the second option, doesn't the existence of the actor in the
> diagram become superfluous? Secondly, depending on the type of activities
> that are being worked on in the system development life cycle, how much
> does it matter whether the actor is portrayed in the diagram or not? I
> realize this also brings in other issues that have troubled me about the
> process for designing user interfaces. How separate should user interface
> design be from functional design? When should the two be brought together
> [though I know in most systems design areas, they aren't separated at all
> in the first place]?
[T] Whenever you decompose a system, you lose meaning. As analysts, we
are responsible for identifying components that add up to a meaningful
system, although we can't actually build the meaning into the individual
components. The UML, like other analysis tools, is an attempt to bring
discipline into the work of creating and maintaining the system, by
representing the relationships between the components in a standardized
way, more abstractly than realizations of the system.
>[Y] "When was the last time you told your interface 'OnOpenButtonClick' ?"
> -Yezierski. Actually, this is a real good point about semantics. One
> of my objects would "hear" the human say "handleClick(openButton)",
> because all messages are injunctive -- they command the object to do
> something. I find that this rule makes it easier for me to understand
> the sequence diagram, and produces a useful semantics at implementation
> time.
>
> For clarification, are you saying that your diagram would include a message
> with corresponding operation "handleClick(openButton)" or include some
> object(s) from the operating system or provided user interface tool set
> that handled that message? Where is the point where you just sort of say
> "the solution is left to the operating system [or to the widgets]"?
[T] Well, despite the code-like appearance, none of these messages
translates directly or reliably into code. The message implies that the
receiving object has the responsibility of handling a click of the Open
button for a window or page of the interface. There may be a direct use
of the message name as code in implementation, but that is not
necessary. The analyst presumes that it is safe to defer developing the
details, in the sense that the details will be implement-able later.
Wherever there is a GUI, I am a great believer in mocking-up the
interface to establish confidence with the customer, and to make a
"contract" of performance. The interface is the point at which the
domain experts (users) and the developers must come together to specify
a useful system. Success in making this specification is dependent on
getting an investment of work from both users and developers, and
requires a rich simulation of user interface, in my experience.
In sequence diagrams for analysis, I don't recall using messages that
approximate "widgets" from the language or the operating system, but I
wouldn't oppose it if it seemed an effective way of specifying the
performance of the system in a particular case. For me, the issue
really hasn't come up. My messages have always turned out to be at
least one level of abstraction above the system calls.
>
> Anyway, thank you for the opportunity to participate in this virtual happy
> hour. To some degree, my academic background (BA in English, minor in
> mathematics; MA in English, emphasis in Film Studies) and inclination in
> life and work have allowed me to put time and thought into how people use
> languages (human, programming, mathematical, statistical, diagrammatic).
> Your query sent me on another ride on my hobby horse.
After all, what is life for?
Obviously, I am enjoying this, too, since I have actually written quite
a lot at a time when I should be either napping or finishing up the
course marks for my students with exceptional cases (most of whom
delivered things late).
-Eric
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