Module: Invoicing::CurrencyValue::Formatter

Defined in:
lib/invoicing/currency_value.rb

Overview

Encapsulates the methods for formatting currency values in a human-friendly way. These methods do not depend on ActiveRecord and can thus also be called externally.

Class Method Summary collapse

Class Method Details

.currency_info(code, options = {}) ⇒ Object

Given the three-letter ISO 4217 code of a currency, returns a hash with useful bits of information:

:code

The ISO 4217 code of the currency.

:round

Smallest unit of the currency in normal use, to which values are rounded. Default is 0.01.

:symbol

Symbol or string usually used to denote the currency. Encoded as UTF-8. Default is ISO 4217 code.

:suffix

true if the currency symbol appears after the number, false if it appears before.

:space

Whether or not to leave a space between the number and the currency symbol.

:digits

Number of digits to display after the decimal point.


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# File 'lib/invoicing/currency_value.rb', line 149

def currency_info(code, options={})
  code = code.to_s.upcase
  valid_options = [:symbol, :round, :suffix, :space, :digits]
  info = {:code => code, :symbol => code, :round => 0.01, :suffix => nil, :space => nil, :digits => nil}
  if ::Invoicing::CurrencyValue::CURRENCIES.has_key? code
    info.update(::Invoicing::CurrencyValue::CURRENCIES[code])
  end
  options.each_pair {|key, value| info[key] = value if valid_options.include? key }

  info[:suffix] ||= (info[:code] == info[:symbol]) && !info[:code].nil?
  info[:space]  ||= info[:suffix]
  info[:digits] = -Math.log10(info[:round]).floor if info[:digits].nil?
  info[:digits] = 0 if info[:digits] < 0

  info
end

.format_value(currency_code, value, options = {}) ⇒ Object

Given the three-letter ISO 4217 code of a currency and a BigDecimal value, returns the value formatted as an UTF-8 string, ready for human consumption.

FIXME: This method currently does not take locale into account – it always uses the dot as decimal separator and the comma as thousands separator.


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# File 'lib/invoicing/currency_value.rb', line 171

def format_value(currency_code, value, options={})
  info = currency_info(currency_code, options)
  
  negative = false
  if value < 0
    negative = true
    value = -value
  end

  value = "%.#{info[:digits]}f" % value
  while value.sub!(/(\d+)(\d\d\d)/, '\1,\2'); end
  value.sub!(/^\-/, '') # avoid displaying minus zero
  
  formatted = if ['', nil].include? info[:symbol]
    value
  elsif info[:space]
    info[:suffix] ? "#{value} #{info[:symbol]}" : "#{info[:symbol]} #{value}"
  else
    info[:suffix] ? "#{value}#{info[:symbol]}" : "#{info[:symbol]}#{value}"
  end
  
  if negative    # default is to use proper unicode minus sign

    formatted = (options[:negative] == :brackets) ? "(#{formatted})" : (
      (options[:negative] == :hyphen) ? "-#{formatted}" : "\xE2\x88\x92#{formatted}"
    )
  end
  formatted
end