NM and CM callable.
Converts a string of characters from phonetic order to screen order or
from screen order to phonetic order.
Operation Notes |
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This intrinsic is designed to handle data for languages written
from right-to-left (for example, ARABIC). Screen order is defined
right-to-left if the primary mode of the terminal or printer is
from right-to-left, as it is when used principally for entering
or displaying data from a right-to-left language. Otherwise,
screen order is defined to be left-to-right.
NLSWITCHBUF can be used by a program to convert a buffer
phonetic order (the order in which the characters is typed
at the terminal or spoken by a person) to screen order (the order
in which the characters are displayed on a terminal screen or
piece of paper). It can also convert data from screen order to
phonetic order.
In general, phonetic order and screen order are not the same
if USASCII text is mixed with text from a right-to-left language.
The relationship between phonetic order and screen order is
further complicated by the use of HINDI digits in ARABIC. (HINDI
digits play a third role intermediate between ASCII characters and
characters of the right-to-left language.)
This intrinsic is designed for a special purpose. Its
primary value lies in its application to languages that are
written from right-to-left and that may intermix
left-to-right text (for example, the use of ENGLISH in ARABIC text).
NLSWITCHBUF can serve the needs of a general
program, one not specifically designed for handling right-to-left
data. A general program can call NLSWITCHBUF to convert data
from phonetic order to screen order and back to phonetic order.
One example is an editor that needs to track cursor movement on a
terminal against a buffer of text in memory. If the data is not
a right-to-left language, then this intrinsic returns the same
text (unchanged); for all other languages, phonetic order and
screen order are the same.
