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 = "n1n" be the input (under the aforementioned conditions), expressed as a string of digits "ni"; then da(n) = n1 + 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".