feat(div): add MustDiv

[vhlebnikov]

It will be very helpful to have such function for big calculation chains, when we sure not dividing by zero

Example (where i need this method):

var duration float64

const hundred = 100.0
roundedDuration, _ := udecimal.MustFromFloat64(value).Div(udecimal.MustFromFloat64(hundred))
roundedDuration = roundedDuration.RoundHAZ(2)
floatRoundedDur := roundedDuration.InexactFloat64()
duration = &floatRoundedDur

And instead of this, I could do:

var duration float64

const hundred = 100.0
roundedDuration := udecimal.MustFromFloat64(value).
		MustDiv(udecimal.MustFromFloat64(hundred)).
		RoundHAZ(2).
		InexactFloat64()
duration = &roundedDuration

[quagmt]

can you add a test for this new method and an example in doc_test.go

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 96.89%. Comparing base (3259bfe) to head (d6ff0ab).
⚠️ Report is 1 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master      #44      +/-   ##
==========================================
+ Coverage   96.41%   96.89%   +0.48%     
==========================================
  Files           5        5              
  Lines        1924     1481     -443     
==========================================
- Hits         1855     1435     -420     
+ Misses         46       23      -23     
  Partials       23       23              

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[xuyang2]

how about add a Must function?

func Must(d Decimal, err error) Decimal {
	if err != nil {
		panic(err)
	}
	return d
}

see also:

• Add a Must function to zap uber-go/zap#640
• Add Must(*Logger, error) *Logger function uber-go/zap#1105

[vhlebnikov]

@xuyang2 I think it will add complexity to the code.

For example, to call Must function you need to prepend call with package name and also wrap all (probably) big line inside, it will be udecimal.Must(...longCalculaationLine...), instead of longCalclulationLine.MustDiv(y).

Just hard to read.

[vhlebnikov]

@quagmt done, check please

[quagmt]

Released this in v1.10.0