# accounting - money and currency formatting for golang
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accounting is a library for money and currency formatting. (inspired by [accounting.js](https://github.com/openexchangerates/accounting.js))


## Quick Start

```
go get github.com/leekchan/accounting
```

example.go

```Go
package main

import (
    "fmt"
    "math/big"

    "github.com/shopspring/decimal"
    "github.com/leekchan/accounting"
)

func main() {
    ac := accounting.Accounting{Symbol: "$", Precision: 2}
    fmt.Println(ac.FormatMoney(123456789.213123))                       // "$123,456,789.21"
    fmt.Println(ac.FormatMoney(12345678))                               // "$12,345,678.00"
    fmt.Println(ac.FormatMoney(big.NewRat(77777777, 3)))                // "$25,925,925.67"
    fmt.Println(ac.FormatMoney(big.NewRat(-77777777, 3)))               // "-$25,925,925.67"
    fmt.Println(ac.FormatMoneyBigFloat(big.NewFloat(123456789.213123))) // "$123,456,789.21"
    fmt.Println(ac.FormatMoneyDecimal(decimal.New(123456789.213123, 0))) // "$123,456,789.21"

    ac = accounting.Accounting{Symbol: "€", Precision: 2, Thousand: ".", Decimal: ","}
    fmt.Println(ac.FormatMoney(4999.99))  // "€4.999,99"

    // Or retrieve currency info from Locale struct
    lc := LocaleInfo["USD"]
    ac = accounting.Accounting{Symbol: lc.ComSymbol, Precision: 2, Thousand: lc.ThouSep, Decimal: lc.DecSep}
    fmt.Println(ac.FormatMoney(500000)) // "$500,000.00"

    ac = accounting.Accounting{Symbol: "£ ", Precision: 0}
    fmt.Println(ac.FormatMoney(500000)) // "£ 500,000"

    ac = accounting.Accounting{Symbol: "GBP", Precision: 0,
        Format: "%s %v", FormatNegative: "%s (%v)", FormatZero: "%s --"}
    fmt.Println(ac.FormatMoney(1000000)) // "GBP 1,000,000"
    fmt.Println(ac.FormatMoney(-5000))   // "GBP (5,000)"
    fmt.Println(ac.FormatMoney(0))       // "GBP --"

    ac = accounting.DefaultAccounting("GBP", 2)
    fmt.Println(ac.FormatMoney(1000000)) // "GBP 1,000,000"
    fmt.Println(ac.FormatMoney(-5000))   // "GBP (5,000)"
    fmt.Println(ac.FormatMoney(0))       // "GBP --"

    ac = accounting.NewAccounting("GBP", 2, ",", ".", "%s %v", "%s (%v)", "%s --")
    fmt.Println(ac.FormatMoney(1000000)) // "GBP 1,000,000"
    fmt.Println(ac.FormatMoney(-5000))   // "GBP (5,000)"
    fmt.Println(ac.FormatMoney(0))       // "GBP --"
}
```

## Caution

Please do not use float64 to count money. Floats can have errors when you perform operations on them. Using [big.Rat](https://golang.org/pkg/math/big/#Rat) (< Go 1.5) or [big.Float](https://golang.org/pkg/math/big/#Float) (>= Go 1.5) is highly recommended.
(accounting supports float64, but it is just for convenience.)

* [FormatMoneyBigFloat(value *big.Float) string](#formatmoneybigfloatvalue-bigfloat-string)
* [FormatMoneyBigRat(value *big.Rat) string](#formatmoneybigratvalue-bigrat-string)

## Initialization

### Accounting struct

```Go
type Accounting struct {
    Symbol         string // currency symbol (required)
    Precision      int    // currency precision (decimal places) (optional / default: 0)
    Thousand       string // thousand separator (optional / default: ,)
    Decimal        string // decimal separator (optional / default: .)
    Format         string // simple format string allows control of symbol position (%v = value, %s = symbol) (default: %s%v)
    FormatNegative string // format string for negative values (optional / default: strings.Replace(strings.Replace(accounting.Format, "-", "", -1), "%v", "-%v", -1))
    FormatZero     string // format string for zero values (optional / default: Format)
}
```

Field | Type | Description | Default | Example
-------------| ------------- | ------------- | ------------- | -------------
Symbol         | string | currency symbol | no default value | $
Precision      | int    | currency precision (decimal places) | 0 | 2
Thousand       | string | thousand separator | , | .
Decimal        | string | decimal separator | . | ,
Format         | string | simple format string allows control of symbol position (%v = value, %s = symbol) | %s%v | %s %v
FormatNegative | string | format string for negative values | strings.Replace(strings.Replace(accounting.Format, "-", "", -1), "%v", "-%v", -1)) | %s (%v)
FormatZero     | string | format string for zero values | Format | %s --

**Examples:**

```Go
# Via functions
ac := accounting.DefaultAccounting("$", 2)
ac := accounting.NewAccounting("$", 2, ",", ".", "%s %v", "%s (%v)", "%s --")

# Via Accounting struct
ac := accounting.Accounting{Symbol: "$", Precision: 2}

ac = accounting.Accounting{Symbol: "€", Precision: 2, Thousand: ".", Decimal: ","}

ac = accounting.Accounting{Symbol: "GBP", Precision: 0,
        Format: "%s %v", FormatNegative: "%s (%v)", FormatZero: "%s --"}
```

## SetThousandSeparator(str string)

SetThousandSeparator sets the separator for the thousands separation

## SetDecimalSeparator(str string)

SetDecimalSeparator sets the separator for the decimal separation

## SetFormat(str string)

SetFormat sets the Format default: `%s%v` (%s=Symbol;%v=Value)

## SetFormatNegative(str string)

SetFormatNegative sets the Format for negative values default: `-%s%v` (%s=Symbol;%v=Value)

## SetFormatZero(str string)

SetFormatZero sets the Format for zero values default: `%s%v` (%s=Symbol;%v=Value)

### Locale struct

```Go
type Locale struct {
    Name           string // currency name
    FractionLength int    // default decimal length
    ThouSep        string // thousands seperator
    DecSep         string // decimal seperator
    SpaceSep       string // space seperator
    UTFSymbol      string // UTF symbol
    HTMLSymbol     string // HTML symbol
    ComSymbol      string // Common symbol
    Pre            bool   // symbol before or after currency
}
```

Field | Type | Description | Default | Example
 -------------| ------------- | ------------- | ------------- | -------------
 Name           | string | currency name | no default value | US Dollar 
 FractionLength | int    | default precision (decimal places) | no default value | 2
 ThouSep        | string | thousand separator | no default value | ,
 DecSep         | string | decimal separator | no default value | .
 SpaceSep       | string | space separator | no default value | " "
 UTFSymbol      | string | UTF symbol | no default value | "0024" 
 HTMLSymbol     | string | HTML symbol | no default value | "&#x0024"
 ComSymbol      | string | Common symbol | no default value | "$"
 Pre            | bool   | symbol before currency | no default value | true

**Example:**

```Go
// LocaleInfo map[string]Locale

var lc Locale
if val, ok := LocaleInfo["USD"]; ok {
    lc = val
} else {
    panic("No Locale Info Found")
}

fmt.Println(lc.Name) // "US Dollar"
fmt.Println(lc.FractionLength) // 2
fmt.Println(lc.ThouSep) // ","
fmt.Println(lc.DecSep) // "."
fmt.Println(lc.SpaceSep) // ""
fmt.Println(lc.UTFSymbol) // "0024"
fmt.Println(lc.HTMLSymbol) // "&#x0024"
fmt.Println(lc.ComSymbol) // "$"
fmt.Println(lc.Pre) // true
```
There are currently 181 currencies supported in LocaleInfo

## FormatMoney(value interface{}) string

FormatMoney is a function for formatting numbers as money values, with customisable currency symbol, precision (decimal places), and thousand/decimal separators.

FormatMoney supports various types of value by runtime reflection. If you don't need runtime type evaluation, please refer to FormatMoneyInt, FormatMoneyBigRat, FormatMoneyBigRat, or FormatMoneyFloat64.

* supported value types : int, int8, int16, int32, int64, uint, uint8, uint16, uint32, uint64, float32, float64, *big.Rat

**Examples:**

```Go
ac := accounting.Accounting{Symbol: "$", Precision: 2}
fmt.Println(ac.FormatMoney(123456789.213123))         // "$123,456,789.21"
fmt.Println(ac.FormatMoney(12345678))                 // "$12,345,678.00"
fmt.Println(ac.FormatMoney(big.NewRat(77777777, 3)))  // "$25,925,925.67"
fmt.Println(ac.FormatMoney(big.NewRat(-77777777, 3))) // "-$25,925,925.67"

ac = accounting.Accounting{Symbol: "€", Precision: 2, Thousand: ".", Decimal: ","}
fmt.Println(ac.FormatMoney(4999.99))  // "€4.999,99"

ac = accounting.Accounting{Symbol: "£ ", Precision: 0}
fmt.Println(ac.FormatMoney(500000)) // "£ 500,000"

ac = accounting.Accounting{Symbol: "GBP", Precision: 0,
    Format: "%s %v", FormatNegative: "%s (%v)", FormatZero: "%s --"}
fmt.Println(ac.FormatMoney(1000000)) // "GBP 1,000,000"
fmt.Println(ac.FormatMoney(-5000))   // "GBP (5,000)"
fmt.Println(ac.FormatMoney(0))       // "GBP --"
```

## FormatMoneyBigFloat(value *big.Float) string

**(>= Go 1.5)**

FormatMoneyBigFloat only supports [*big.Float](https://golang.org/pkg/math/big/#Float) value. It is faster than FormatMoney, because it does not do any runtime type evaluation.

**Examples:**

```Go
ac = accounting.Accounting{Symbol: "$", Precision: 2}
fmt.Println(ac.FormatMoneyBigFloat(big.NewFloat(123456789.213123))) // "$123,456,789.21"
fmt.Println(ac.FormatMoneyBigFloat(big.NewFloat(12345678)))         // "$12,345,678.00"

ac = accounting.Accounting{Symbol: "€", Precision: 2, Thousand: ".", Decimal: ","}
fmt.Println(ac.FormatMoneyBigFloat(big.NewFloat(4999.99)))  // "€4.999,99"

ac = accounting.Accounting{Symbol: "£ ", Precision: 0}
fmt.Println(ac.FormatMoneyBigFloat(big.NewFloat(500000))) // "£ 500,000"

ac = accounting.Accounting{Symbol: "GBP", Precision: 0,
    Format: "%s %v", FormatNegative: "%s (%v)", FormatZero: "%s --"}
fmt.Println(ac.FormatMoneyBigFloat(big.NewFloat(1000000))) // "GBP 1,000,000"
fmt.Println(ac.FormatMoneyBigFloat(big.NewFloat(-5000)))   // "GBP (5,000)"
fmt.Println(ac.FormatMoneyBigFloat(big.NewFloat(0)))       // "GBP --"
```

## FormatMoneyInt(value int) string

FormatMoneyInt only supports int value. It is faster than FormatMoney, because it does not do any runtime type evaluation.

**Examples:**

```Go
ac = accounting.Accounting{Symbol: "$", Precision: 2}
fmt.Println(ac.FormatMoneyInt(12345678)) // "$12,345,678.00"

ac = accounting.Accounting{Symbol: "€", Precision: 2, Thousand: ".", Decimal: ","}
fmt.Println(ac.FormatMoneyInt(4999))  // "€4.999,00"

ac = accounting.Accounting{Symbol: "£ ", Precision: 0}
fmt.Println(ac.FormatMoneyInt(500000)) // "£ 500,000"

ac = accounting.Accounting{Symbol: "GBP", Precision: 0,
    Format: "%s %v", FormatNegative: "%s (%v)", FormatZero: "%s --"}
fmt.Println(ac.FormatMoneyInt(1000000)) // "GBP 1,000,000"
fmt.Println(ac.FormatMoneyInt(-5000))   // "GBP (5,000)"
fmt.Println(ac.FormatMoneyInt(0))       // "GBP --"
```

## FormatMoneyBigRat(value *big.Rat) string

FormatMoneyBigRat only supports [*big.Rat](https://golang.org/pkg/math/big/#Rat) value. It is faster than FormatMoney, because it does not do any runtime type evaluation.

**Examples:**

```Go
ac = accounting.Accounting{Symbol: "$", Precision: 2}
fmt.Println(ac.FormatMoneyBigRat(big.NewRat(77777777, 3)))  // "$25,925,925.67"
fmt.Println(ac.FormatMoneyBigRat(big.NewRat(-77777777, 3))) // "-$25,925,925.67"

ac = accounting.Accounting{Symbol: "€", Precision: 2, Thousand: ".", Decimal: ","}
fmt.Println(ac.FormatMoneyBigRat(big.NewRat(77777777, 3)))  // "€25.925.925,67"

ac = accounting.Accounting{Symbol: "£ ", Precision: 0}
fmt.Println(ac.FormatMoneyBigRat(big.NewRat(77777777, 3)))  // "£ 25,925,926"

ac = accounting.Accounting{Symbol: "GBP", Precision: 0,
    Format: "%s %v", FormatNegative: "%s (%v)", FormatZero: "%s --"}
fmt.Println(ac.FormatMoneyBigRat(big.NewRat(77777777, 3)))  // "GBP 25,925,926"
fmt.Println(ac.FormatMoneyBigRat(big.NewRat(-77777777, 3))) // "GBP (25,925,926)"
fmt.Println(ac.FormatMoneyBigRat(big.NewRat(0, 3)))         // "GBP --"
```

## FormatMoneyFloat64(value float64) string

FormatMoneyFloat64 only supports float64 value. It is faster than FormatMoney, because it does not do any runtime type evaluation.

**Examples:**

```Go
ac = accounting.Accounting{Symbol: "$", Precision: 2}
fmt.Println(ac.FormatMoneyFloat64(123456789.213123)) // "$123,456,789.21"
fmt.Println(ac.FormatMoneyFloat64(12345678))         // "$12,345,678.00"

ac = accounting.Accounting{Symbol: "€", Precision: 2, Thousand: ".", Decimal: ","}
fmt.Println(ac.FormatMoneyFloat64(4999.99))  // "€4.999,99"

ac = accounting.Accounting{Symbol: "£ ", Precision: 0}
fmt.Println(ac.FormatMoneyFloat64(500000)) // "£ 500,000"

ac = accounting.Accounting{Symbol: "GBP", Precision: 0,
    Format: "%s %v", FormatNegative: "%s (%v)", FormatZero: "%s --"}
fmt.Println(ac.FormatMoneyFloat64(1000000)) // "GBP 1,000,000"
fmt.Println(ac.FormatMoneyFloat64(-5000))   // "GBP (5,000)"
fmt.Println(ac.FormatMoneyFloat64(0))       // "GBP --"
```

## FormatNumber(value interface{}, precision int, thousand string, decimal string) string

FormatNumber is a base function of the library which formats a number with custom precision and separators. 

FormatNumber supports various types of value by runtime reflection. If you don't need runtime type evaluation, please refer to FormatNumberInt, FormatNumberBigRat, or FormatNumberFloat64.

* supported value types : int, int8, int16, int32, int64, uint, uint8, uint16, uint32, uint64, float32, float64, *big.Rat

**Examples:**

```Go
fmt.Println(accounting.FormatNumber(123456789.213123, 3, ",", ".")) // "123,456,789.213"
fmt.Println(accounting.FormatNumber(1000000, 3, " ", ","))          // "1 000 000,000"
```

## FormatNumberBigFloat(value *big.Float, precision int, thousand string, decimal string) string

**(>= Go 1.5)**

FormatNumberBigFloat only supports [*big.Float](https://golang.org/pkg/math/big/#Float) value. It is faster than FormatNumber, because it does not do any runtime type evaluation.

**Examples:**

```Go
fmt.Println(accounting.FormatNumberBigFloat(big.NewFloat(123456789.213123), 3, ",", ".")) // "123,456,789.213"
```

## FormatNumberInt(value int, precision int, thousand string, decimal string) string

FormatNumberInt only supports int value. It is faster than FormatNumber, because it does not do any runtime type evaluation.

**Examples:**

```Go
fmt.Println(accounting.FormatNumberInt(123456789, 3, ",", ".")) // "123,456,789.000"
```

## FormatNumberBigRat(value *big.Rat, precision int, thousand string, decimal string) string

FormatNumberBigRat only supports [*big.Rat](https://golang.org/pkg/math/big/#Rat) value. It is faster than FormatNumber, because it does not do any runtime type evaluation.

**Examples:**

```Go
fmt.Println(accounting.FormatNumberBigRat(big.NewRat(77777777, 3), 3, ",", ".")) // "25,925,925.667"
```

## FormatNumberFloat64(value float64, precision int, thousand string, decimal string) string

FormatNumberFloat64 only supports float64 value. It is faster than FormatNumber, because it does not do any runtime type evaluation.

**Examples:**

```Go
fmt.Println(accounting.FormatNumberFloat64(123456789.213123, 3, ",", ".")) // "123,456,789.213"
```

## FormatNumberDecimal(value decimal.Decimal, precision int, thousand string, decimal string) string

FormatNumberDecimal only supports [decimal.Decimal](https://github.com/shopspring/decimal) value. It is faster than FormatNumber, because it does not do any runtime type evaluation.

**Examples:**

```Go
import "github.com/shopspring/decimal"
fmt.Println(accounting.FormatNumberBigDecimal(apd.New(apd.New(4999999, -3), 3, ",", ".")) // "4,999.999"
```

## FormatNumberBigDecimal(value apd.Decimal, precision int, thousand string, decimal string) string

FormatNumberDecimal only supports [apd.Decimal](https://github.com/cockroachdb/apd) value. It is faster than FormatNumber, because it does not do any runtime type evaluation.

**Examples:**

```Go
import "github.com/cockroachdb/apd"
fmt.Println(accounting.FormatNumberDecimal(decimal.New(123456789.213123,3), 3, ",", ".")) // "123,456,789.213"
```

## UnformatNumber(number string, precision int, currency string) string

UnformatNumber is the inverse of FormatNumber. It strips out all currency formatting and returns the number with a point for the decimal seperator. 

**Examples:**

```Go
fmt.Println(accounting.UnformatNumber("$45,000.50", 2, "USD")) // "45000.50"
fmt.Println(accounting.UnformatNumber("EUR 12.500,3474", 3, "EUR")) // "12500.347"
```