Improve simplification of physical quantities

[sharkdp]

An input like

5Mbit/s * 2h

should be simplified to 36 Gbit, i.e. units of the same dimension should always be unified (here: second and hour). Similarly

5cm * 5m

should be simplified to either 0.25m² or 2500cm²

This is related to sharkdp/purescript-quantities#16

[itdaniher]

Possibly related:

Welcome to insect. Type '?' if this is your first visit.
> 1 watt -> joules
Cannot unify unit 'W' with unit 'J'
> joules
1J
> watt
1W

compare to gnu units expansion and simplification:

You have: 1 watt
You want: 1 joule
conformability error
        1 kg m^2 / s^3
        1 kg m^2 / s^2
You have: 1 watt
You want:
        Definition: 1 kg m^2 / s^3
You have: 1 joule
You want:
        Definition: 1 kg m^2 / s^2

the latter explains this issue at hand and relates it to physical quantities, allowing a user to debug their expression.

This is by far my favorite feature of gnu units and make-or-break for a CAS-like system that offers dimensional analysis and unit conversion.

Definitely interesting work overall, I would love to see this replace connectbot + gnu units or wolfram for basic engineering math.

Regards!

[sharkdp]

@itdaniher That's a cool feature, indeed! Thank you for the feedback... I think this is something that could be implemented rather easily.

[itdaniher]

Happy to share! I'll be keeping an eye on this project for sure.

[sharkdp]

@itdaniher This feature is now supported:

> 1 watt -> joules
Unification error:
  Cannot unify unit W (base units: m²·g/s³)
          with unit J (base units: m²·g/s²)

> g0 * 40s + 5m
Unification error:
  Cannot unify unit m (base units: m)
          with unit m/s (base units: m/s)

[sharkdp]

Simplification is now supported:

>>> 5Mbit/s * 2h

  (5Mbit / s) × 2h

   = 36000Mbit

>>> 5cm * 5m

  5cm × 5m

   = 2500cm²

>>> 120km/h * 2min

  (120km / h) × 2min

   = 4km