Rim uses CHARACTER variables and constants for messages and
for internal communication but most text, and all
character data on file, is represented by 7-bit ASCII codes
in integer variables. Thus, for example, when the integer
variable CH contains 97 it represents a lower case `a'.
A variable containing a single ascii character is
call an `ascii-char'.
To reduce memory requirements ascii characters are often
packed and stored in arrays. Words of 32 or 36 bits
can hold 4 characters; words of 60 or 64 bits
can hold 8 characters. An integer array containing
packed characters is called `ascii-text'.