Community documentation for Janet

> (eprin "there is a boo-boo on line " 33 "\n")
there is a boo-boo on line 33
nil

(eval-string "(+ 1 2 3 4)") # -> 10
(eval-string ")") # -> parse error
(eval-string "(bloop)") # -> compile error
(eval-string "(+ nil nil)") # -> runtime error

(def channel (ev/chan))

(ev/spawn
 (do
   (for i 0 10
     (ev/give channel (math/random))
     (ev/sleep 0.25))
   (ev/chan-close channel)))

(defn consumer [name delay]
  (loop [item :iterate (ev/take channel)]
    (match item
      [:close _] nil
      v (print name " got " v))))

(ev/call consumer "bob" 1)
(ev/call consumer "alice" 3)

(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         ]

(keyword/slice "some crazy keyword" 11 -1)
# returns :keyword 

@[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]

# channels that can be used for communication between os threads
(def chan-a (ev/thread-chan 10))
(def chan-b (ev/thread-chan 10))

# one thread
(ev/thread
  (fiber/new
    (fn []
      (def msg "hi")
      (print "thread 1 sending: " msg)
      (ev/give chan-a msg)
      #
      (print "thread 1 received: " (ev/take chan-b))))
  :1
  :n)

# another thread
(ev/thread
  (fiber/new
    (fn []
      (print "thread 2 received: " (ev/take chan-a))
      #
      (def msg "peace")
      (print "thread 2 sending: " msg)
      (ev/give chan-b msg)))
  :2
  :n)

# expected output
#
# thread 1 sending: hi
# thread 2 received: hi
# thread 2 sending: peace
# thread 1 received: peace

(abstract? (file/temp))  # => true
(abstract? (int/s64 1))  # => true

(map abstract?  [ nil true 97 'a :a "a" ])
# => @[false false false false false false]

(map abstract?  [ [97]  @[97]  {0 97}  @{0 97} ])
# => @[false false false false]

(map abstract?  [ even? loop file/open  (fn [])  ])
# => @[false false false false]

(map abstract?  [ (file/temp)  (fiber/new (fn []))  ])
# => @[true false]

(string/trimr " foo ")  # => " foo"
(string/trimr "_!_foo_!_" "_!")  # => "_!_foo"

(string/replace "+" "-" "ctrl+c")
# => "ctrl-c"

(eachk k {:a "a val" :b "b val" :c "c val"} (print k))
# prints c
# prints a
# prints b

(keyword :)
# => :

(get      [4 5 6]   -1     )  # => nil
(in       [4 5 6]   -1  42 )  # error
(get-in   [4 5 6]  [-1] 42 )  # => 42

(get     {:a 1}   -1     )  # => nil
(in      {:a 1}   -1  42 )  # => 42
(get-in  {:a 1}  [-1] 42 )  # => 42

# note, if running a server from the repl, you need to (quit) your repl.

# in a terminal:
# $ while true; do date | nc 0.0.0.0 1234 -w 1; sleep 1; done

# in a janet repl:
(net/server "0.0.0.0" 1234
  (fn [conn]
    (prin (net/read conn 4096))
    (net/close conn)))
# output doesn't actually start until you (quit) your repl's fiber:
(quit)

(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)]      ]