Community documentation for Janet

# opens a file named filename for writing, and writes Hello World!
(def f (file/open "filename" :w))
(file/write f "Hello World!")
(file/flush f)
(file/close f)

(map bytes?      [ 'ab   :ab   "ab"   @"ab"  [97 98]  @[97 98]  {0 97 1 98}  @{0 97 1 98}  ])
# =>            @[ true  true  true   true   false    false     false        false         ]

(map symbol?     [ 'ab   :ab   "ab"   @"ab"  [97 98]  @[97 98]  {0 97 1 98}  @{0 97 1 98}  ])
# =>            @[ true  false false  false  false    false     false        false         ]

(map keyword?    [ 'ab   :ab   "ab"   @"ab"  [97 98]  @[97 98]  {0 97 1 98}  @{0 97 1 98}  ])
# =>            @[ false true  false  false  false    false     false        false         ]

(map string?     [ 'ab   :ab   "ab"   @"ab"  [97 98]  @[97 98]  {0 97 1 98}  @{0 97 1 98}  ])
# =>            @[ false false true   false  false    false     false        false         ]

(map buffer?     [ 'ab   :ab   "ab"   @"ab"  [97 98]  @[97 98]  {0 97 1 98}  @{0 97 1 98}  ])
# =>            @[ false false false  true   false    false     false        false         ]

# can execute query from a file like:
(db/query (slurp "db/sql/random.sql"))

# In context:
(defn show [request]
  (when-let [[name] (request :wildcard)
             name (uri/unescape name) # escaping is important for = and especially %
             name (string/replace "_q" "?" name)
             binding (first (db/query (slurp "db/sql/search.sql") [name]))]

    [:vstack {:spacing "m"}
     (binding-header binding)
     (examples/index (merge request {:binding binding}))]))

# From https://codeberg.org/veqq/janetdocs/src/commit/ac1dc9e3e82f17e8e9ac047297b00803b68034d0/routes/examples.janet#L217

(int/u64 "18446744073709551615")
# => <core/u64 18446744073709551615>

@[1 2 3]                 # -> @[1 2 3]
(array 1 2 3)            # -> @[1 2 3]
(array (splice [1 2 3])  # -> @[1 2 3]
(array ;[1 2 3])         # -> @[1 2 3]

(pp (all-bindings))
# => prints @[% %= * ... yield zero? zipcoll]

(def a "A")
(pp (all-bindings (curenv) true))
# => prints @[_ a] - only local bindings are listed

(string/ascii-upper "hello")  # => "HELLO"

(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

(do
  (def coll @[])
  (forv i 0 9
    (array/push coll i)
    (+= i 2))
  coll)
# => @[0 3 6]

(table/to-struct @{:a 1}) # => {:a 1}

(drop 1 "smile")
# => "mile"

(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   ]

(let [len 8
      rand-string (string/join (map |(string/format "%02x" $)
                                    (os/cryptorand len)))]
  (= (length rand-string) (* 2 len)))
# => true

(array/new-filled 3)     # => @[nil nil nil]
(array/new-filled 3 :a)  # => @[:a :a :a]

(mean [1 10 100])  # => 37
(mean [])          # => nan