Addition

Produces a result by computing the numeric sum of its left and right operands. If the two operands are both expressions of type integer, then integral addition is performed and the result is of type integer. If the two operands are both of type decimal or both of type float, then floating-point addition is performed and the result type is the same as the operand type.

Subtraction

Produces a result by computing the numeric difference between the left and right operands by subtracting the value of the right operand from the left. If the two operands are both expressions of type integer, then integral subtraction is performed and the result is of type integer. If the two operands are both of type decimal or both of type float, then floating-point subtraction is performed and the result type is the same as the operand type.

String concatenation

Produces a result by adding two strings or a string and an another type together. If only one operand expression is of type string, then string conversion is performed on the other operand to produce a string. The result is a new string whose value is the value or string value of the right operand appended to the value or string value of the left operand. The result type of the string concatenation operator is string. Operand expression of type chunk, stream or action cannot be concatenated to an operand expression of type string. If an operand expression is of type any, then the contents of the any are converted to string to produce an expression of type string.