That article is missing several concepts which are essential for
understanding Unicode; like many programmers, Mr. Spolsky thinks of
Unicode as "wide ASCII", which it is not. The article doesn't cover
surrogate pairs (the fact that he uses the term UCS-2 instead of
UTF-16 shows he's not up to date) or combining sequences (grapheme
clusters). If you're going to go groveling through Unicode text, you
need to understand both.
This article is a bit stuffy, but also more complete, and is even
shorter (I think):
Maybe I'm spoiled on Spolsky's breezy style, but I found this article
confusing and painful to read. It uses the term "code point" several
times before defining it two-thirds of the way down. In the first
paragraph it dives right into acronyms and version numbers without
defining a single concept:
"[...] Versions of the Unicode Standard are fully compatible and
synchronized with the corresponding versions of International Standard
ISO/IEC 10646. For example, Unicode 5.1 contains all the same
characters and encoding points as ISO/IEC 10646:2003 plus amendments.
[...] Any implementation that is conformant to Unicode is also
conformant to ISO/IEC 10646."
For those who find the above intro fascinating, I won't keep you in
suspense. The article ends like this:
"The Unicode encoding forms correspond exactly to forms of use and
transformation formats also defined in ISO/IEC 10646. UTF-8 and UTF-16
are defined in Annexes to ISO/IEC 10646. And UTF-32 corresponds to the
four-octet form UCS-4 of ISO/IEC 10646."
I found this much clearer and better-written than the first document
you referenced. It defines terms and concepts in an orderly
progression. But I would have found it drier and more difficult if I
hadn't read Spolsky first. Unless Spolsky is plainly, misleadingly,
dangerously wrong about something, I would recommend his article first
for anyone (like me) who needs to bone up on this stuff.
--Andy
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