Community documentation for Janet

(empty? [])
# => true

(odd? 2) # => false
(odd? nil) # throws an error
(odd? 1) # => true
(odd? "a") # => throws an error

# removes a file in the current directory
(os/rm "hello.txt")

# Due to: https://github.com/swlkr/janetdocs/issues/50

(defn parse-date
  "Parses YYYY-MM-DD date format to time"
  [date]
  (let [[year month day] (map scan-number (string/split "-" date))]
    (os/mktime {:year year :month (dec month) :month-day (dec day)})))

(print (parse-date "2021-01-01")) # 1609459200
(print (os/strftime "%c" (parse-date "2021-01-01"))) # Fri Jan  1 00:00:00 2021

(var x 5)
(%= x 3)
(pp x) # 2

(freeze @{:a @[1 2] 
          :b @{:x @[8 9] 
               :y :smile}})
# => {:a (1 2) :b {:x (8 9) :y :smile}}

(math/hypot 1 1)  # => 1.41421
(math/sqrt 2)     # => 1.41421

(array/pop (range 12)) # => 11

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

(buffer/bit-set @"hahaha" 3) # => @"hahaha"

(buffer/bit-set @"what" 3) # => @"\x7Fhat"

(string/reverse "hello") # => "olleh"

(disasm (fn []) :bytecode)
# => @[(retn)]

# in the file ex.janet

(main [_ & args]
      (print "write something and I'll echo it")
      (def x (getline))
      (print x))

# in the terminal:
# $ janet ex.janet
# write something and I'll echo it
# bla <- you wrote this
# bla

(update @[3 4 5] 1 dec)  # => @[3 3 5]
(update (update @[3 4 5] 1 dec) 2 inc)  # => @[3 3 6]

(put  @{:a 4 :b 5}  :c 6         )  # => @{:a 4 :b 5 :c 6}
(put  @{:a 4 :b 5}  :b nil       )  # => @{:a 4}
(put  @{:a 4 :b 5}  :z nil       )  # => @{:a 4 :b 5}

(put  @[:a :b :c]   0  :z        )  # => @[:z :b :c]
(put  @[:a :b :c]   1  nil       )  # => @[:a nil :c]

(put  @[:a :b :c]   5  :d        )  # => @[:a :b :c nil nil :d]

(put  @"hello"      0  "z"       )  # error: can only put integers in buffers
(defn ord [ch] (first (string/bytes ch)))
(ord "z")  # => 122
(put  @"hello"      0  122       )  # => @"zello"
(put  @"hello"      0  (ord "z") )  # => @"zello"
(put  @"hello"      8  (ord "y") )  # => @"hello\0\0\0y"