Checking in vendor folder for ease of using go get.

vendor/golang.org/x/text/currency/format.go

@@ -0,0 +1,215 @@
+// Copyright 2015 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package currency
+
+import (
+	"fmt"
+	"io"
+	"sort"
+
+	"golang.org/x/text/internal"
+	"golang.org/x/text/internal/format"
+	"golang.org/x/text/language"
+)
+
+// Amount is an amount-currency unit pair.
+type Amount struct {
+	amount   interface{} // Change to decimal(64|128).
+	currency Unit
+}
+
+// Currency reports the currency unit of this amount.
+func (a Amount) Currency() Unit { return a.currency }
+
+// TODO: based on decimal type, but may make sense to customize a bit.
+// func (a Amount) Decimal()
+// func (a Amount) Int() (int64, error)
+// func (a Amount) Fraction() (int64, error)
+// func (a Amount) Rat() *big.Rat
+// func (a Amount) Float() (float64, error)
+// func (a Amount) Scale() uint
+// func (a Amount) Precision() uint
+// func (a Amount) Sign() int
+//
+// Add/Sub/Div/Mul/Round.
+
+var space = []byte(" ")
+
+// Format implements fmt.Formatter. It accepts format.State for
+// language-specific rendering.
+func (a Amount) Format(s fmt.State, verb rune) {
+	v := formattedValue{
+		currency: a.currency,
+		amount:   a.amount,
+		format:   defaultFormat,
+	}
+	v.Format(s, verb)
+}
+
+// formattedValue is currency amount or unit that implements language-sensitive
+// formatting.
+type formattedValue struct {
+	currency Unit
+	amount   interface{} // Amount, Unit, or number.
+	format   *options
+}
+
+// Format implements fmt.Formatter. It accepts format.State for
+// language-specific rendering.
+func (v formattedValue) Format(s fmt.State, verb rune) {
+	var lang int
+	if state, ok := s.(format.State); ok {
+		lang, _ = language.CompactIndex(state.Language())
+	}
+
+	// Get the options. Use DefaultFormat if not present.
+	opt := v.format
+	if opt == nil {
+		opt = defaultFormat
+	}
+	cur := v.currency
+	if cur.index == 0 {
+		cur = opt.currency
+	}
+
+	// TODO: use pattern.
+	io.WriteString(s, opt.symbol(lang, cur))
+	if v.amount != nil {
+		s.Write(space)
+
+		// TODO: apply currency-specific rounding
+		scale, _ := opt.kind.Rounding(cur)
+		if _, ok := s.Precision(); !ok {
+			fmt.Fprintf(s, "%.*f", scale, v.amount)
+		} else {
+			fmt.Fprint(s, v.amount)
+		}
+	}
+}
+
+// Formatter decorates a given number, Unit or Amount with formatting options.
+type Formatter func(amount interface{}) formattedValue
+
+// func (f Formatter) Options(opts ...Option) Formatter
+
+// TODO: call this a Formatter or FormatFunc?
+
+var dummy = USD.Amount(0)
+
+// adjust creates a new Formatter based on the adjustments of fn on f.
+func (f Formatter) adjust(fn func(*options)) Formatter {
+	var o options = *(f(dummy).format)
+	fn(&o)
+	return o.format
+}
+
+// Default creates a new Formatter that defaults to currency unit c if a numeric
+// value is passed that is not associated with a currency.
+func (f Formatter) Default(currency Unit) Formatter {
+	return f.adjust(func(o *options) { o.currency = currency })
+}
+
+// Kind sets the kind of the underlying currency unit.
+func (f Formatter) Kind(k Kind) Formatter {
+	return f.adjust(func(o *options) { o.kind = k })
+}
+
+var defaultFormat *options = ISO(dummy).format
+
+var (
+	// Uses Narrow symbols. Overrides Symbol, if present.
+	NarrowSymbol Formatter = Formatter(formNarrow)
+
+	// Use Symbols instead of ISO codes, when available.
+	Symbol Formatter = Formatter(formSymbol)
+
+	// Use ISO code as symbol.
+	ISO Formatter = Formatter(formISO)
+
+	// TODO:
+	// // Use full name as symbol.
+	// Name Formatter
+)
+
+// options configures rendering and rounding options for an Amount.
+type options struct {
+	currency Unit
+	kind     Kind
+
+	symbol func(compactIndex int, c Unit) string
+}
+
+func (o *options) format(amount interface{}) formattedValue {
+	v := formattedValue{format: o}
+	switch x := amount.(type) {
+	case Amount:
+		v.amount = x.amount
+		v.currency = x.currency
+	case *Amount:
+		v.amount = x.amount
+		v.currency = x.currency
+	case Unit:
+		v.currency = x
+	case *Unit:
+		v.currency = *x
+	default:
+		if o.currency.index == 0 {
+			panic("cannot format number without a currency being set")
+		}
+		// TODO: Must be a number.
+		v.amount = x
+		v.currency = o.currency
+	}
+	return v
+}
+
+var (
+	optISO    = options{symbol: lookupISO}
+	optSymbol = options{symbol: lookupSymbol}
+	optNarrow = options{symbol: lookupNarrow}
+)
+
+// These need to be functions, rather than curried methods, as curried methods
+// are evaluated at init time, causing tables to be included unconditionally.
+func formISO(x interface{}) formattedValue    { return optISO.format(x) }
+func formSymbol(x interface{}) formattedValue { return optSymbol.format(x) }
+func formNarrow(x interface{}) formattedValue { return optNarrow.format(x) }
+
+func lookupISO(x int, c Unit) string    { return c.String() }
+func lookupSymbol(x int, c Unit) string { return normalSymbol.lookup(x, c) }
+func lookupNarrow(x int, c Unit) string { return narrowSymbol.lookup(x, c) }
+
+type symbolIndex struct {
+	index []uint16 // position corresponds with compact index of language.
+	data  []curToIndex
+}
+
+var (
+	normalSymbol = symbolIndex{normalLangIndex, normalSymIndex}
+	narrowSymbol = symbolIndex{narrowLangIndex, narrowSymIndex}
+)
+
+func (x *symbolIndex) lookup(lang int, c Unit) string {
+	for {
+		index := x.data[x.index[lang]:x.index[lang+1]]
+		i := sort.Search(len(index), func(i int) bool {
+			return index[i].cur >= c.index
+		})
+		if i < len(index) && index[i].cur == c.index {
+			x := index[i].idx
+			start := x + 1
+			end := start + uint16(symbols[x])
+			if start == end {
+				return c.String()
+			}
+			return symbols[start:end]
+		}
+		if lang == 0 {
+			break
+		}
+		lang = int(internal.Parent[lang])
+	}
+	return c.String()
+}