helper function to access formatters by keyword

(f/cache f/+format-cache+ nil java.text.SimpleDateFormat “HH MM dd Z” true)

converts a date into a string

(f/format (Date. 0) “HH MM dd Z” {:timezone “GMT” :cached true}) => “00 01 01 +0000”

(f/format (common/calendar (Date. 0) (TimeZone/getTimeZone “GMT”)) “HH MM dd Z” {}) => “00 01 01 +0000”

(f/format (Timestamp. 0) “HH MM dd Z” {:timezone “PST”}) => “16 12 31 -0800”

(f/format (Date. 0) “HH MM dd Z”) => string?

testing format for java.time datastructures (-> (f/parse “00 00 01 01 01 1989 +0000” “ss mm HH dd MM yyyy Z” {:type Clock}) (map/to-map {} common/+default-keys+)) => {:type java.time.Clock$FixedClock, :timezone “Etc/GMT” :long 599619600000, :year 1989, :month 1, :day 1, :hour 1, :minute 0, :second 0, :millisecond 0}

(-> (f/parse “00 00 01 01 01 1989 -1000” “ss mm HH dd MM yyyy Z” {:type Clock}) (map/to-map {} common/+default-keys+)) => {:type java.time.Clock$FixedClock, :timezone “Etc/GMT-10”, :long 599583600000, :year 1989, :month 1, :day 1, :hour 1, :minute 0, :second 0, :millisecond 0}

(-> (f/parse “00 00 01 01 01 1989 +1000” “ss mm HH dd MM yyyy Z” {:type Clock}) (map/to-map {} common/+default-keys+)) => {:type java.time.Clock$FixedClock, :timezone “Etc/GMT+10”, :long 599655600000, :year 1989, :month 1, :day 1, :hour 1, :minute 0, :second 0, :millisecond 0}