Unary Operator Expressions

General

Unary operator expressions are expressions that consist of an operator prefix followed by an expression operand. An important thing to note is that the operand of a unary operator expression is expected to be a non-pointer type. If the operand has a pointer type, then it is automatically dereferenced.

Unary operators

Hyper has the following unary operators:

The first three operators in the table are straightforward for anyone who knows Java or C++. The last two, however, need some explanation.

The successor expression may look like a pre-increment, but it is not!. In fact, the successor expression does what its name says: it just gives the value right after the value of its operand. For example, ++5 gives 6 as a result. Likewise, the expression --5 returns the value 4. Those two expressions don't modify their operand, so they do not require their operand to be an L-value. If you need increment or decrement that changes its operand, then take a look at the increment/decrement statements.

Example

procedure p()
  var a & b & c & d : int
  a = 12
  b = 9
  c = ++a   # c becomes 12 + 1 = 13
  d = ++b * --b  # d becomes (9 + 1) * (9 - 1) = 10 * 8 = 80
  c = - -- -- + a   # c becomes -((+12 - 1) - 1) = -10
  var s : bool = !false  # s is true
end

See also

• Expressions
• Operator precedence
• Increment/decrement statement