Community documentation for Janet

(def b @"")
(xprint b "HOHOHO")
# => nil
b
# => @"HOHOHO\n"

(repeat 12 (-> 12 os/cryptorand pp))

# => @"\xA7li[ \xED\xD2\xF7O\xD6\x15="
# => @">\"-w+\x04\x1C\xC1KG\x9C\xE4"
# => @"\x06b\f\xBD\x12\x19\xB6\x1A\xCA\xB9[\x85"
# => @"\xBE`R\t\x13\x81\xED\x9D#\xD0\x11!"
# => @"\xE2\xC1\xD8\x7F\\\xA7\x84\xC0\v\x8B'\x98"
# => @"\xD6\x0Fz\x86\xE2\xB2\x1D}\xC6'{\xB5"
# => @"\x9D\x97\xA1\x07i\x9FW\x83h4n2"
# => @"d\x8E\xB8\xBA \xA6\x9C\f\xC6\xAD{g"
# => @"\r\xB5\xF84#\xB8c~V\xD7d>"
# => @"\xBB\x19\xB2\xDC\x8B\xD9\x7F\xDC\xBE\f\x88\xE3"
# => @"w\xB50\xF9\xFD\xEB\x1D\xFF:j]\xB8"
# => @"\x8F$\xEBKL~\xFD\t\xA8\xD1\x8C\xC5"
# => nil

(or true)        # => true
(or true true)   # => true
(or true false)  # => true

(or false 1 2)  # => 1
(or false 2 1)  # => 2

(or false nil)  # => nil
(or nil false)  # => false

# note that `or` does not behave as you might expect
# when used with `apply` and `splice`:
(or 1 2 3)             # => 1
(or (splice [1 2 3]))  # => (1 2 3)
(apply or [1 2 3])     # => (if 1 1 (if 2 2 3))

(defn read-from-file [file-path]
  (let [f (file/open file-path :r)
        content  (file/read f :all)]
    (file/close f)
    content))

### USAGE 

(read-from-file "/path/to/file-read-example.janet")
# => @"(defn read-from-file [file-path]\n  (let [f (file/open file-path :r)\n        content  (file/read f :all)]\n    (file/close f)\n    content))\n"

(map number? [nil   true  42   :a    "a"   []    {}    (fn []) ])
# =>        @[false false true false false false false false   ]

(map math/abs   [-2.9 -2.1 2.1 2.9])  # => @[ 2.9  2.1  2.1  2.9 ]
(map math/floor [-2.9 -2.1 2.1 2.9])  # => @[ -3   -3   2    2   ]
(map math/ceil  [-2.9 -2.1 2.1 2.9])  # => @[ -2   -2   3    3   ]
(map math/round [-2.9 -2.1 2.1 2.9])  # => @[ -3   -2   2    3   ]
(map math/trunc [-2.9 -2.1 2.1 2.9])  # => @[ -2   -2   2    2   ]

(try
  (error :fun)
  ([e]
   (= e :fun)))
# => true

(string/join @["alice" "bob" "eve"] "\t")
# => "alice\tbob\teve"

(keyword "")
# => :

(defn ddup [ds ks val]
  (update-in ds ks
    (fn [x]
      (if (= nil x)
        @[val]
        (array/push x val)))))

(var a @{})
(ddup a [:a] 1)
(ddup a [:a] 2)
(ddup a [:a] 3)
# @{:a @[1 2 3]}

(band 7 11)  # => 3

#     0111  (7)
# and 1011  (11)
# --------
#     0011  (3)

(map  |($ {:a 7 :b 8} )   [  keys      values    kvs             pairs                 ])
# =>                     @[  @[:a :b]  @[7 8]    @[:a 7 :b 8]    @[(:a 7) (:b 8)]      ]

(map  |($ [4 5 6] )       [  keys      values    kvs             pairs                 ])
# =>                     @[  @[0 1 2]  @[4 5 6]  @[0 4 1 5 2 6]  @[(0 4) (1 5) (2 6)]  ]

(map  |($ 'ab )           [  keys      values    kvs             pairs                 ])
# =>                     @[  @[0 1]    @[97 98]  @[0 97 1 98]    @[(0 97) (1 98)]      ]

(map  |($ :ab )           [  keys      values    kvs             pairs                 ])
# =>                     @[  @[0 1]    @[97 98]  @[0 97 1 98]    @[(0 97) (1 98)]      ]

(map  |($ "ab" )          [  keys      values    kvs             pairs                 ])
# =>                     @[  @[0 1]    @[97 98]  @[0 97 1 98]    @[(0 97) (1 98)]      ]

(let [a 1 b 2 c 3] (+ a b c))  # => 6

(let
  [a 1
   b (+ a 1)
   c (+ b 1)]
  (+ a b c))  # => 6

(let [tbl @{:a 1}]
  (merge-into tbl {:b 2})
  tbl)
# => @{:a 1 :b 2}

# real-world example: https://git.sr.ht/~subsetpark/bagatto/tree/19aea03fe23fe5486890912df7dc4a936ce617a3/item/main.janet#L23

# excess elements of the longer list are discarded
(interleave [1] 
            [2 4] 
            [3 6])
# -> @[1 2 3]