Thank you very much for the feedback!

This is on purpose (see operator precedence rules: https://github.com/sharkdp/insect#reference). Implicit multiplication (without an explicit multiplication operator) has a higher precedence than division in order for something like this to work:

  tan(15cm/3m)

  = tan(15cm/(3m))

On the other hand, explicit multiplication has a lower precedence than division, so you would have to write "1/12*c". I agree that it can be confusing at times (that's why there is a pretty printer), but I don't want the language/parser to be whitespace-aware.

Apparently unit-less constants should bind stronger:

1/4 s - > (1/4) s

1 m / 4 s - > (1 m) / (4 s)