Method: Date.parse_spec

Defined in:
lib/fat_core/date.rb

.parse_spec(spec, spec_type = :from) ⇒ Object

Convert a ‘date spec’ to a Date. A date spec is a short-hand way of

specifying a date, relative to the computer clock.  A date spec can
interpreted as either a 'from spec' or a 'to spec'.

@example
Assuming that Date.current at the time of execution is 2014-07-26 and
using the default spec_type of :from.  The return values are actually Date
objects, but are shown below as textual dates.

A fully specified date returns that date:
    Date.parse_spec('2001-09-11')  # =>

Commercial weeks can be specified using, for example W32 or 32W, with the
week beginning on Monday, ending on Sunday.
    Date.parse_spec('2012-W32')    # =>
    Date.parse_spec('2012-W32', :to) # =>
    Date.parse_spec('W32') # =>

A spec of the form Q3 or 3Q returns the beginning or end of calendar
quarters.
    Date.parse_spec('Q3')         # =>

@param spec [#to_s] a stringling containing the spec to be interpreted
@param spec_type [:from, :to] interpret the spec as a from- or to-spec
  respectively, defaulting to interpretation as a to-spec.
@return [Date] a date object equivalent to the date spec



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# File 'lib/fat_core/date.rb', line 66

def self.parse_spec(spec, spec_type = :from)
  spec = spec.to_s.strip
  unless [:from, :to].include?(spec_type)
    raise ArgumentError "invalid date spec type: '#{spec_type}'"
  end

  today = Date.current
  case spec
  when /^(\d\d\d\d)-(\d\d?)-(\d\d?)*$/
    # A specified date
    Date.new($1.to_i, $2.to_i, $3.to_i)
  when /\AW(\d\d?)\z/, /\A(\d\d?)W\z/
    week_num = $1.to_i
    if week_num < 1 || week_num > 53
      raise ArgumentError, "invalid week number (1-53): 'W#{week_num}'"
    end
    spec_type == :from ? Date.commercial(today.year, week_num).beginning_of_week :
      Date.commercial(today.year, week_num).end_of_week
  when /\A(\d\d\d\d)-W(\d\d?)\z/, /\A(\d\d\d\d)-(\d\d?)W\z/
    year = $1.to_i
    week_num = $2.to_i
    if week_num < 1 || week_num > 53
      raise ArgumentError, "invalid week number (1-53): 'W#{week_num}'"
    end
    spec_type == :from ? Date.commercial(year, week_num).beginning_of_week :
      Date.commercial(year, week_num).end_of_week
  when /^(\d\d\d\d)-(\d)[Qq]$/, /^(\d\d\d\d)-[Qq](\d)$/
    # Year-Quarter
    year = $1.to_i
    quarter = $2.to_i
    unless [1, 2, 3, 4].include?(quarter)
      raise ArgumentError, "bad date format: #{spec}"
    end
    month = quarter * 3
    spec_type == :from ? Date.new(year, month, 1).beginning_of_quarter :
      Date.new(year, month, 1).end_of_quarter
  when /^([1234])[qQ]$/, /^[qQ]([1234])$/
    # Quarter only
    this_year = today.year
    quarter = $1.to_i
    date = Date.new(this_year, quarter * 3, 15)
    spec_type == :from ? date.beginning_of_quarter : date.end_of_quarter
  when /^(\d\d\d\d)-(\d\d?)*$/
    # Year-Month only
    spec_type == :from ? Date.new($1.to_i, $2.to_i, 1) :
      Date.new($1.to_i, $2.to_i, 1).end_of_month
  when /\A(\d\d?)\z/
    # Month only
    spec_type == :from ? Date.new(today.year, $1.to_i, 1) :
      Date.new(today.year, $1.to_i, 1).end_of_month
  when /^(\d\d\d\d)$/
    # Year only
    spec_type == :from ? Date.new($1.to_i, 1, 1) : Date.new($1.to_i, 12, 31)
  when /^(to|this_?)?day/
    today
  when /^(yester|last_?)?day/
    today - 1.day
  when /^(this_?)?week/
    spec_type == :from ? today.beginning_of_week : today.end_of_week
  when /last_?week/
    spec_type == :from ? (today - 1.week).beginning_of_week :
      (today - 1.week).end_of_week
  when /^(this_?)?biweek/
    spec_type == :from ? today.beginning_of_biweek : today.end_of_biweek
  when /last_?biweek/
    spec_type == :from ? (today - 2.week).beginning_of_biweek :
      (today - 2.week).end_of_biweek
  when /^(this_?)?semimonth/
    spec_type == :from ? today.beginning_of_semimonth : today.end_of_semimonth
  when /^last_?semimonth/
    spec_type == :from ? (today - 15.days).beginning_of_semimonth :
      (today - 15.days).end_of_semimonth
  when /^(this_?)?month/
    spec_type == :from ? today.beginning_of_month : today.end_of_month
  when /^last_?month/
    spec_type == :from ? (today - 1.month).beginning_of_month :
      (today - 1.month).end_of_month
  when /^(this_?)?bimonth/
    spec_type == :from ? today.beginning_of_bimonth : today.end_of_bimonth
  when /^last_?bimonth/
    spec_type == :from ? (today - 2.month).beginning_of_bimonth :
      (today - 2.month).end_of_bimonth
  when /^(this_?)?quarter/
    spec_type == :from ? today.beginning_of_quarter : today.end_of_quarter
  when /^last_?quarter/
    spec_type == :from ? (today - 3.months).beginning_of_quarter :
      (today - 3.months).end_of_quarter
  when /^(this_?)?year/
    spec_type == :from ? today.beginning_of_year : today.end_of_year
  when /^last_?year/
    spec_type == :from ? (today - 1.year).beginning_of_year :
      (today - 1.year).end_of_year
  when /^forever/
    spec_type == :from ? Date::BOT : Date::EOT
  when /^never/
    nil
  else
    raise ArgumentError, "bad date spec: '#{spec}''"
  end # !> previous definition of length was here
end