Placing each operator at its own precedence level subtly alters the
evaluation order for +, -, *, and /, which can produce unexpected
results where rounding errors are considered.

More significantly, the precendence of % differs from that used in
C (and various other languages). For example,

2 * 3.1 % 2  with C precedence would be
(2 * 3.1) % 2 = 6.2 % 2 = 0.2   (unlike C's %, our % if really fmod)

By giving % higher precedence than *, we get
2 * (3.1 % 2) = 2 * 1.1 = 2.2  instead.

I don't know if this difference is intentional, e.g., required for
compatibility with Milkdrop. But it does at least look suspicious.

- Werner