Tuesday, February 1, 2011

Special Character usage in Visionary

Hex codes are base 16 vice our daily base 10 decimal system. These characters or hex digits are, 0 1 2 3 4 5 6 7 8 9 A B C D E F. They are listed like this to make it obvious they are not decimal numbers, “x00” for zero decimal, through “xFF” for 255 decimal. Basic ASCII text usage is the first 128 characters; hex 00 through 7F. The first 32 hex codes are of interest only to us geeks, and are called the non-printable characters. From hex 20 (x20) or decimal 32, through x7F or decimal 127; are all the valid ASCII characters. This consists of the digits, the upper case letters, the lower case letters and about 34 special characters (such as the period, comma, plus sign, etc.)

Since this stops halfway to xFF, there are many other possible two character hex codes. Everything from x80 through FF. It has become a non-standard “standard” practice to map these to other characters. This mapping depends on what character set you are using. For instance, there is a mapping for the Cyrillic alphabet, the Greek alphabet, etc. Each of these character mappings use the hex codes greater than x7F. Word processing programs and other text generation programs can use a default character mapping and add in 128 more characters. But they are not ASCII text files and rely on the use of the appropriate character mapping.

All Visionary software is designed to use the ASCII character set.

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