Implement initial simple denom convert utils

[alexanderbez]

Implement denom registration and a coin conversion utility.

This assumes we do not touch ParseCoin/s. IMHO, that should only take in the base denom -- uatom.

/cc @cwgoes @rigelrozanski

ref: #3510

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[codecov]

Codecov Report

Merging #3747 into develop will increase coverage by 0.03%.
The diff coverage is 77.77%.

@@             Coverage Diff             @@
##           develop    #3747      +/-   ##
===========================================
+ Coverage    60.95%   60.98%   +0.03%     
===========================================
  Files          192      193       +1     
  Lines        14360    14386      +26     
===========================================
+ Hits          8753     8774      +21     
- Misses        5033     5035       +2     
- Partials       574      577       +3

[cwgoes]

What about just one function, "ConvertDenom", which takes an amount, a source denom, and a desired denom, and converts one to the other (if the denoms are recognized)? Then we can easily add new denoms without changing the function calls.

[jackzampolin]

Related to the work: https://github.com/cosmos/cosmos-sdk/pull/3813/files

[alexanderbez]

@cwgoes @rigelrozanski bump <3

[jleni]

Would it be possible to use SI prefixes correctly?

[cwgoes]

Would it be possible to use SI prefixes correctly?

Absolutely let's do - what should we change?

[alexanderbez]

We should at the very least use u|uatom|10^-6 and m|matom|10^-3. Thoughts @jleni?

[rigelrozanski]

I don't think we should be using anything except uatom and atom in this tool - everything else just adds confusion AFIAC. Also I think the unit's are off based on what I'm seeing in the code (Bez's comment seems correct though, confusingly) https://www.google.com/search?q=si+prefixes&source=lnms&tbm=isch&sa=X&ved=0ahUKEwjCxMfutvvgAhULpYMKHQFUAD4Q_AUIDigB&biw=1269&bih=696#imgrc=F26w4WQUVJaWDM:

[alexanderbez]

@rigelrozanski Those are standard de-facto SI prefixes. We should've caught this sooner tbh. Also, wrt to only atom and uatom. This functionality makes no assumptions on denoms -- it can be used by any developer/application. For Gaia, it'll only have atom and uatom.

[cwgoes]

I don't see why we should avoid other prefixes - uatom can stay the actual denomination, and the tooling can default to show (and maybe accept values) in atom.

[alexanderbez]

@cwgoes @rigelrozanski @jleni updated

[rigelrozanski]

Couple minor comments to make things a bit more clear - but looks good. Also you're right, I forgot this is the util not the gaia implementation, so nbd about using a bunch of SI examples

[alexanderbez]

Updated. Should be good to merge.

[alexanderbez]

Bump @cwgoes

[cwgoes]

Needs a changelog entry, otherwise the code LGTM.

I wonder if we should warn the user somehow when truncation results in loss of precision.

[alexanderbez]

Added a pending log entry @cwgoes

[alexanderbez]

Fixed CI and added pending log entry @cwgoes