Round tripping Quantities through String

[jdm204]

Hi, thanks for the package, nice to have an alternative approach to the Unitful type-based one.

Is there a way in this package to convert back and fourth between Quantities and String representations so that quantities could be serialised to strings and parsed back again? Like in Unitful, string(q::Quantity) prints a space between the last numeral and the unit, which yields an error with uparse.

[MilesCranmer]

Just so I understand, would you want a way to parse the current pretty-printed output? Or would you want to have a printing function that gives something you can directly type into the REPL?

[MilesCranmer]

Btw, is there a function in Base for prints that aim to give a string representation that can be typed back into the REPL? Like some show(::IO, ::Val{:raw}, x) or something?

[jdm204]

Just so I understand, would you want a way to parse the current pretty-printed output? Or would you want to have a printing function that gives something you can directly type into the REPL?

I suppose either would suit my needs, maybe parsing units with the space might make more sense as "2 mL"/1 nM" etc is a pretty common way to write these quantities for humans!

Btw, is there a function in Base for prints that aim to give a string representation that can be typed back into the REPL? Like some show(::IO, ::Val{:raw}, x) or something?

I was looking and didn't find it, though I did realise I don't understand Julia's display system as well as I should.

Also worth noting a similar issue with Unitful: JuliaPhysics/Unitful.jl#470

[michikawa07]

This michikawa07/UnitfulParsableString.jl may be helpful as a temporary solution.

[MilesCranmer]

Nice! Would be great if you added DQ support, as I think it should basically work out-of-the-box here too with DynamicQuantities.uparse. So just need a parsable_string method for DQ.Quantity objects.

P.S., I think at the moment UnitfulParsableString.jl relies on type piracy so would be good to rework it: https://docs.julialang.org/en/v1/manual/style-guide/#avoid-type-piracy. I think just having a new function symbol called parsable_string might be good.