4 * Allow use of "ASCII" and "EBCDIC" for "indexes", "digits",
5 * and "Control-Characters".
7 * Note that all "index" values must be "lowercase letters", while
8 * all "digits" must be "digits". Control characters can be made
9 * from any legal characters.
11 #define A2I(X) ((X) - 'a')
12 #define I2A(X) ((char)(X) + 'a')
13 #define D2I(X) ((X) - '0')
14 #define I2D(X) ((X) + '0')
15 #define KTRL(X) ((X)&0x1F)