mekso unary operator: digital addition.

Denoted "da" here. Output is in the base of the input (when defined); input should typically be a nonnegative integer expressed in a traditional positional base (such as standard decimal or hexadecimal). Let n = "n_{1n}" be the input (under the aforementioned conditions), expressed as a string of digits "n_{i}"; then da(n) = n_{1 + n}, where the lhs has the input expressed in some implicit acceptable base and the rhs matches it. Endianness-independent for the standard situation herein defined. See also: "su'i'o".

- su'i'o
*(exp!)* - mekso unary or binary operator: ordered inputs (n, b) where n and b are nonnegative integers and b > 1; output is the ultimate digital root of n in base-b.