Held Tuesday, September 3, 2002
Summary
Today we begin to ground our understanding of computer science
with hands-on practice. In particular, we'll look at some of the procedures
necessary for building documents for the World Wide Web.
Notes
- Returning to the
Why don't more people use Scheme?
question:
It may be a return to the old VHS vs. Beta (or Windows vs. Mac or Unix)
question: People don't always use what's best, and don't always understand
what criteria they should use.
Assignments
Overview
We may not cover this section explicitly, but it gives you some things
to think about.
- HTML is the markup language used for the World Wide Web.
- Unlike a programming language, which describes algorithms, HTML is
simply a markup language. Markup languages describe data.
- Some of the same questions come up as you consider how the computer
might represent any document. For example, a typical word-processed
document will have different margins, font, and justification at different
parts of the document.
- Should a human be able to tell what's going on; or can it all
be
computer gibberish
?
- What do you have to represent in a document? Nearly everything:
- The content of the document
- Something about each piece of the document
- General document characteristics (e.g., page margins)
- ...
- We say that a language for representing documents includes
mark up
symbols that indicate these characteristics.
- In considering markup, there are two general
philosophies
for
what you mark: logical markup and physical markup.
- In logical markup, you indicate the role of each
piece of text. For example, you might indicate that
-
This is a paragraph
-
This is an important word or phrase
-
This is a quotation
-
This is the title of a book
-
This is a top-level section heading in a paper
- In physical markup, you indicate the appearance of
each piece of text. For example, you might indicate that
-
This should appear in Times Bold 12pt
-
This should appear in a box 2 inches each side that is placed
3/4 inch from the top margin and 5 inches from the right margin
- I'm a strong proponent of logical markup. Why?
- Different
people have different expectations about the appearance of certain
logical items
- Physical appearance does not necessarily
indicate the logical role, even when the author of a document
may intend you to do so.
- Consider book titles. What should a book title look like in a
formatted document?
- Consider italicized words. Why do you expect to see a
word (or words) in italics?
- I also worry that too much emphasis on physical markup leads
non-designers to commit unreadable documents.
- HTML is a simple markup language created for the World Wide Web.
- HTML is intended to be human readable.
- Some would dispute that claim.
- HTML is a particular form of SGML, the Standard Generalized
Markup Language
- SGML was designed by a number of scholars for representing
electronic manuscripts.
- Full SGML can even describe layout of pages so that one can
precisely represent documents like the Talmud.
- In HTML, parts of the document are surrounded by tags.
- Tags give information about those parts of the document.
- Each tag begins with a less-than sign and ends with a
greater-than sign.
- End tags have a slash after the less-than sign.
- For example,
- You begin a paragraph with
<p> and end
a paragraph with </p>.
- You begin an important word or phrase with
<em>
and end it with </em>.
- You begin a list of items with
<ul> and
end it with </ul>.
- You begin an item in that list with
<li> and
end it with </li>.
- You begin a numbered list with
<ol> and
end it with </ol>.
- You begin a piece of text in a
typewriter font
with
<tt> and end it with </tt>.
- Some tags do not require end tags. Some even disallow end tags.
For example,
-
<br> is a line break. Since there's not text
that you're marking, it needs no end tag.
-
<br> is a horizontal rule.
- The
<li> tag does not need an end tag
(since the next <li> or the ending
<ul> obviously
ends it).
- Some tags permit you to enter parameters: more information
about how the text should be displayed. For example, you can write
-
<p align="right"> for right-justified text
-
<hr width="75%"> for a less-wide rule
-
<font face="Helvetica" color="Red"> for
red, Helvetica text.
- Since much of this course is hands on, let's get started.
- See the accompanying laboratory
handout.
- Do the HTML lab.
- Raise your hand if you have a question.
- If you don't finish it all today, try to work on
it tonight (or later).
- Complete understanding of this lab is not required to progress to the
next lab.
What have you learned today?
Thursday, 29 August 2002
Monday, 2 September 2002
- Added the getting started in the MathLAN lab, taken from the previous
outline.
;
Check with Bobby