* print(...strings and values...) -- Prints to stderr.  Very useful to 'probe' an expression.
                                       Evaluates to the last value.
                                       Example: `print("x is", x, "and y is", y)`
                                       Example: `x + print("y:", y) + z == x+y+z`

  * log(base=10, val) -- Logarithm with optional 'base' as first argument.
                         If not provided, 'base' defaults to '10'.
                         Example: `log(100) + log(e(), 100)`

  * e()  -- Euler's number (2.718281828459045)
  * pi() -- π (3.141592653589793)

  * int(val)
  * ceil(val)
  * floor(val)
  * round(modulus=1, val) -- Round with optional 'modulus' as first argument.
                             Example: `round(1.23456) == 1  &&  round(0.001, 1.23456) == 1.235`

  * abs(val)
  * sign(val)

  * min(val, ...) -- Example: `min(1, -2, 3, -4) == -4`
  * max(val, ...) -- Example: `max(1, -2, 3, -4) == 3`

  * sin(radians)    * asin(val)
  * cos(radians)    * acos(val)
  * tan(radians)    * atan(val)
  * sinh(val)       * asinh(val)
  * cosh(val)       * acosh(val)
  * tanh(val)       * atanh(val)