[
Lists Home |
Date Index |
Thread Index
]
"Roger L. Costello" <costello@mitre.org> wrote in message
200501121345.j0CDj1v18371@smtp-bedford-dr.mitre.org">news:200501121345.j0CDj1v18371@smtp-bedford-dr.mitre.org...
> Hi Folks,
>
> Suppose that:
>
> 1. There exist a collection of "components", and each component is
> well-defined and understood.
>
> 2. There does NOT exist any rules which specify how the components should
> be
> assembled.
>
> If I assemble some of the components into a certain structure, and send
> the
> structure to you, will you be able to understand my structure?
The question is very generic. There are cases where the answer is positive.
Take FXSL:
- Most of the functions and operators don't know about the existence of
other functions.
- Most/all functions can be combined in any arbitrary ways (that only
must satisfy type rules) through functional composition
- The result is easily understood, even in some more complicated cases
An example:
f:map(f:flip(f:round-half-to-even(f:sqrt(2, 0.000001))), 0 to 13)
It is not too difficult to conclude that this evaluates to a list of
numbers, each of which is a rounding of sqrt(2) (with precision of 0.000001)
and the respective number of digits after the decimal point (from o to 13
digits after the decimal point).
So, one is not surprised to see the following result:
1
1.4
1.41
1.414
1.4142
1.41421
1.414214
1.4142136
1.41421356
1.414213562
1.4142135624
1.41421356237
1.414213562375
1.4142135623747
So, there are systems (any system with support for higher-order functions),
where it is possible to combine components in almost arbitrary ways and this
is "by design".
Cheers,
Dimitre Novatchev
>
> Let me be a bit more concrete. Suppose that:
>
> 1. There exist a collection of information components, and each
> information
> component is well-defined and understood. Some examples of information
> components might include - a missile information component (this component
> provides information about a missile, such as its direction, speed,
> warhead
> type, etc), an aircraft information component (this component provides
> information about an aircraft, such as its altitude, wingspan, speed,
> etc).
>
> 2. There does NOT exist any rules which specify how the information
> components should be assembled. In other words, there is no grammar which
> dictates how the components must be bound together.
>
> If I assemble some of the information components into a certain structure,
> and send the structure to you, will you be able to understand my
> information
> structure?
>
> Can information be transmitted in a world where the building blocks are
> understood, but no grammar exists?
>
> Is a grammar necessary for information transfer?
>
> Let me give a simple example. Suppose that:
>
> 1. There exists these three components - A, B, C. And everyone knows the
> meaning of each component.
>
> 2. There are no rules that specify how A, B, or C should be organized, nor
> the number of occurrences of each.
>
> Suppose that I create this message: AACABBAC. And I send it to you. Will
> you be able to understand my message?
>
> Consider the English language. Suppose that:
>
> 1. The English language was just comprised of a bunch of words (and each
> word is understood), ...
>
> 2. ... but there was no English grammar.
>
> If I compose a sentence using these words, will you be able to understand
> my
> sentence?
>
> Consider XML Schemas. Suppose that:
>
> 1. An XML Schema declares a bunch of independent elements (i.e.,
> components)
> and each component is understood. For example, here's a Book component:
>
> <xsd:element name="Book">
> <xsd:complexType>
> <xsd:all>
> <xsd:element name="Title" type="xsd:string"/>
> <xsd:element name="Author" type="xsd:string"/>
> <xsd:element name="Date" type="xsd:date"/>
> <xsd:element name="ISBN" type="xsd:string"/>
> <xsd:element name="Publisher" type="xsd:string"/>
> </xsd:all>
> </xsd:complexType>
> </xsd:element>
>
> Here's a BookCover component:
>
> <xsd:element name="BookCover">
> <xsd:complexType>
> <xsd:choice>
> <xsd:element name="Hardcover"><xsd:complexType/></xsd:element>
> <xsd:element name="Softcover"><xsd:complexType/></xsd:element>
> </xsd:choice>
> </xsd:complexType>
> </xsd:element>
>
> Everyone understands the meaning of each component in the Schema.
>
> 2. But there is no declaration tying the components together, e.g., there
> is
> no overarching element declaration that relates the Book component with
> the
> BookCover component.
>
> If I create an XML instance document using the components and send the
> instance document to you, will you be able to understand my data?
>
> /Roger
>
>
>
>
> -----------------------------------------------------------------
> The xml-dev list is sponsored by XML.org <http://www.xml.org>, an
> initiative of OASIS <http://www.oasis-open.org>
>
> The list archives are at http://lists.xml.org/archives/xml-dev/
>
> To subscribe or unsubscribe from this list use the subscription
> manager: <http://www.oasis-open.org/mlmanage/index.php>
>
>
|
