3.6.6. let - evaluate arithmetic expressions

3.6.6.1. Usage

let EXPR [EXPR ...]

3.6.6.2. Synopsis

Supported operations are in order of decreasing precedence:
      X++, X--
      ++X, --X
      +X, -X
      !X, ~X
      X**Y
      X*Y, X/Y, X%Y
      X+Y, X-Y
      X<<Y, X>>Y
      X<Y, X<=Y, X>=Y, X>Y
      X==Y, X!=Y
      X&Y
      X^Y
      X|Y
      X&&Y
      X||Y
      X?Y:Z
      X*=Y, X/=Y, X%=Y
      X=Y, X&=Y, X|=Y, X^=Y, X+=Y, X-=Y, X<<=Y, X>>=Y