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Recognizing special patterns makes renderings sound more
natural. Consider how experienced readers speak math
expressions. Even though [tex2html_wrap5738] is spoken as ``the
fraction a plus b divided by c'', [tex2html_wrap5740] is spoken
as ``one half a''. In addition, mathematical notation is
inherently ambiguous, with the same notational construct being
overloaded to mean different things in different contexts.
Thus, the [tex2html_wrap5742]'s in [tex2html_wrap5744] and
[tex2html_wrap5746] have different meanings. The recognizer
treats both occurrences of the [tex2html_wrap5748] as a visual
attribute of the object being superscripted. The decision to
treat the [tex2html_wrap5750] appearing as a superscript to the
function as denoting the function inverse is made by rendering
rules based on special patterns.
Since such interpretation is context sensitive, the
quasi-prefix representation is enhanced -before an object is
rendered, special-pattern (a memoized[+] function) is called to
identify special patterns. A user can specify
additional patterns by providing method definitions on function
special-pattern for specific object types. These
special patterns can then be turned on by calling
(turn-on-special-pattern object-name).
The user can provide rendering rules named pattern
for object object, which get invoked when the
particular special pattern is seen. Individual special patterns
can be turned off by executing statement
(turn-off-special-pattern object-name).
All special patterns can be turned off by deactivating style
use-special-patterns.
Special patterns built into AsTeR include:
- [tex2html_wrap5752] as the superscript is interpreted as
squaring, [tex2html_wrap5754] as cubing etc.
- [tex2html_wrap5756] as the superscript of a valid matrix
expression denotes transpose.
- [tex2html_wrap5758] as the superscript of a function name
denotes function inverse.
- [tex2html_wrap5760] denotes a derivative.
TV Raman
Thu Mar 9 20:10:41 EST 1995