feat: add Dec.Float64() function

CHANGELOG.md

@@ -53,6 +53,7 @@ if input key is empty, or input data contains empty key.
 * [#9088](https://github.com/cosmos/cosmos-sdk/pull/9088) Added implementation to ADR-28 Derived Addresses.
 * [\#9133](https://github.com/cosmos/cosmos-sdk/pull/9133) Added hooks for governance actions.
 * (x/staking) [\#9214](https://github.com/cosmos/cosmos-sdk/pull/9214) Added `new_shares` attribute inside `EventTypeDelegate` event.
+* [\#9382](https://github.com/cosmos/cosmos-sdk/pull/9382) feat: add Dec.Float64() function.
 
 ### Client Breaking Changes
 

types/decimal.go

@@ -474,6 +474,22 @@ func (d Dec) String() string {
 	return string(bzStr)
 }
 
+// Float64 returns the float64 representation of a Dec.
+// Will return the error if the conversion failed.
+func (d Dec) Float64() (float64, error) {
+	return strconv.ParseFloat(d.String(), 64)
+}
+
+// MustFloat64 returns the float64 representation of a Dec.
+// Would panic if the conversion failed.
+func (d Dec) MustFloat64() float64 {
+	if value, err := strconv.ParseFloat(d.String(), 64); err != nil {
+		panic(err)
+	} else {
+		return value
+	}
+}
+
 //     ____
 //  __|    |__   "chop 'em
 //       ` \     round!"

types/decimal_test.go

@@ -100,6 +100,28 @@ func (s *decimalTestSuite) TestDecString() {
 	}
 }
 
+func (s *decimalTestSuite) TestDecFloat64() {
+	tests := []struct {
+		d    sdk.Dec
+		want float64
+	}{
+		{sdk.NewDec(0), 0.000000000000000000},
+		{sdk.NewDec(1), 1.000000000000000000},
+		{sdk.NewDec(10), 10.000000000000000000},
+		{sdk.NewDec(12340), 12340.000000000000000000},
+		{sdk.NewDecWithPrec(12340, 4), 1.234000000000000000},
+		{sdk.NewDecWithPrec(12340, 5), 0.123400000000000000},
+		{sdk.NewDecWithPrec(12340, 8), 0.000123400000000000},
+		{sdk.NewDecWithPrec(1009009009009009009, 17), 10.090090090090090090},
+	}
+	for tcIndex, tc := range tests {
+		value, err := tc.d.Float64()
+		s.Require().Nil(err, "error getting Float64(), index: %v", tcIndex)
+		s.Require().Equal(tc.want, value, "bad Float64(), index: %v", tcIndex)
+		s.Require().Equal(tc.want, tc.d.MustFloat64(), "bad MustFloat64(), index: %v", tcIndex)
+	}
+}
+
 func (s *decimalTestSuite) TestEqualities() {
 	tests := []struct {
 		d1, d2     sdk.Dec