Community documentation for Janet

(var x 1)
(+= x 2 3 4)
# x = 10

(defn to-double-digit-string [digit]
  (string/slice (string "0" digit) -3))

(defn get-date-time-string [time]
  (let [date (os/date time)
        year (get date :year)
        month (to-double-digit-string (get date :month))
        day (to-double-digit-string (get date :month-day))
        hours (to-double-digit-string (get date :hours))
        minutes (to-double-digit-string (get date :minutes))
        seconds (to-double-digit-string (get date :seconds))]
    (string year "-" month "-" day "__" hours ":" minutes ":" seconds)))

(defn get-current-date-time-string []
  (get-date-time-string (os/time)))


### USAGE

(get-current-date-time-string)
# => "2020-09-23__17:20:00"

(import spork/misc)
(def d (misc/capout (doc misc/capout)))

d # returns:
@"\n\n    macro\n    /usr/local/lib/janet/spork/misc.janet on 
line 340, column 1\n\n    \e[97m(capout & body)\e[39m\n\n   
 Captures the standard output of the variadic \e[97mbody\e[39m
 and returns it as \n    a buffer.\n\n\n"

(defn dataframe 
  ``Create an empty dataframe with the given columns``
  [& columns]
  (tabseq [c :in columns] c @[]))

(string/find-all "duck" "duck duck duck goose!") # => @[0 5 10]

# This turns the current REPL session (environment) with all bindings, including synced closures,
# into a loadable or compilable image.
# It is the same as e.g.: `janet -c test.janet test.jimage` after (spit "test.janet" (currenv))

 (spit "test.jimage" (make-image (curenv)))

(put (table) :a 1) # => @{:a 1}

(def add17 (partial + 17))
(add17 3)            # -> 20
(add17 3 4)          # -> 24
(map add17 [1 2 3])  # -> @[18 19 20]

(math/atan2 0 0)
# => 0

(find |(string/has-prefix? "a" $) ["be" "cat" "art" "apple"])

# => "art"

(cmp 1.0 2)
# => -1

(map hash [nil true false -1 0 3.14 :a "foo" [1 2 3] {:a 1} (fn [])])
# => @[0 1 0 -1074790400 0 1244950043 -2107123988 -1254832049 -2021739803 -1395744911 53378043]

(def [pipe-r pipe-w] (os/pipe))
(:write pipe-w "hello")
(:read pipe-r 5)
# => @"hello"

# send the string "hello" into the writable stream
# part and read it back from the readable one

(buffer ;(interpose " " [:ant 'bee "cat" ``dog`` @`ewe`]))
# => @"ant bee cat dog ewe"

(peg/find-all ~(capture :d)
              "hi 0 bye 1")
# => @[3 9]