// unaryExpr generates code unary operators (+a, -a, ~a, !a, etc).
func (c *compiler) unaryExpr(e *ast.UnaryExpr, lv *arch.LV) *node {
pos := e.Span().Start
n := c.exprInternal(e.X, lv)
var x opcode
switch op := e.Op.Type; op {
case scan.Inc, scan.Dec:
switch {
case op == scan.Inc && e.Affix == ast.Prefix:
x = opPreInc
case op == scan.Inc && e.Affix == ast.Postfix:
x = opPostInc
case op == scan.Dec && e.Affix == ast.Prefix:
x = opPreDec
case op == scan.Dec && e.Affix == ast.Postfix:
x = opPostDec
}
n = newNode(x, lv, nil, n, nil)
lv.Addressable = false
case scan.Plus:
n = c.rvalue(n, lv)
lv.Addressable = false
case scan.Minus, scan.Negate, scan.Not:
switch op {
case scan.Minus:
x = opNeg
case scan.Negate:
x = opNot
case scan.Not:
x = opLogNot
}
n = c.rvalue(n, lv)
n = newNode(x, lv, nil, n, nil)
lv.Addressable = false
case scan.And:
if lv.Addressable && lv.Ident {
n = newNode(opAddr, lv, nil, n, nil)
}
lv.Addressable = false
default:
c.errorf(pos, "invalid unary expression %v", op)
}
return n
}
// incOrDec type checks an expression for ++/-- operators.
func (c *checker) incOrDec(x *operand, e *ast.UnaryExpr, op scan.Type) {
Y := &ast.BasicLit{scan.Token{scan.Number, e.Span().Start, "1"}}
c.binary(x, e.X, Y, op)
}