+ (Addition Operator)
Adds numbers, concatenates strings or lists, and merges maps. Map entries from the right operand replace matching keys on the left. Integer operands give an int; if the result overflows, the Arith handler installed around the code chooses the value. Constant expressions such as the one below are evaluated at compile time. See Arithmetic Effects.
With a float operand, the result is a float. Floating-point arithmetic follows IEEE-754: infinity and NaN remain values, and underflow preserves subnormal values and signed zero. It does not request an integer overflow policy. See the float result contract.
Example
let result = 5 + 3 // result = 8result = 5 + 3 // result = 8