Community documentation for Janet

(def person-ids {"Alice" 42 "Bob" 23})

(keep person-ids ["Carl" "Bob" "Alice"])   # -> @[23 42]

(filter person-ids ["Carl" "Bob" "Alice"]) # -> @["Bob" "Alice"]
(map person-ids ["Carl" "Bob" "Alice"])    # -> @[nil 23 42]

(chr "a")  # => 97

(string "hello " "world") # => "hello world"

(fiber/root) # => <fiber 0x562FF22F10A0> your hex number will differ

(keyword? :a)   # => true
(keyword? "a")  # => false

(def f (file/temp))
(file/write f "ok stuff")
(file/seek f :set 0)
(file/read f :all)

# N.b. file/temp's file is not accessible outside of the process

(find-index |(= $ "b") ["a" "b" "c" "d"]) #=> 1

(loop [i :range [0 12]]
  (print i))

# => 0
# => 1
# => 2
# => 3
# => 4
# => 5
# => 6
# => 7
# => 8
# => 9
# => 10
# => 11
# => nil

(= math/-inf (- math/-inf 1))
# =>
true

(keyword :)
# => :

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

(inc 42)  # => 43
(map inc [1 2 3])  # => @[2 3 4]

(slice [:a :b :c :d])  # => (:a :b :c :d)

(slice [:a :b :c :d] 0)  # => (:a :b :c :d)
(slice [:a :b :c :d] 1)  # => (:b :c :d)
(slice [:a :b :c :d] 3)  # => (:d)
(slice [:a :b :c :d] 4)  # => ()
(slice [:a :b :c :d] 5)  # error: index out of range

(slice [:a :b :c :d] -1)  # => ()
(slice [:a :b :c :d] -2)  # => (:d)
(slice [:a :b :c :d] -4)  # => (:b :c :d)
(slice [:a :b :c :d] -5)  # => (:a :b :c :d)
(slice [:a :b :c :d] -6)  # error: index out of range

(slice [:a :b :c :d] 0 0)  # => ()
(slice [:a :b :c :d] 0 1)  # => (:a)
(slice [:a :b :c :d] 0 4)  # => (:a :b :c :d)

(slice [:a :b :c :d] -1 -1)  # => ()
(slice [:a :b :c :d] -2 -1)  # => (:d)
(slice [:a :b :c :d] -5 -1)  # => (:a :b :c :d)

(slice [:a :b :c :d] 1 0)  # => ()
(slice [:a :b :c :d] 4 0)  # => ()
(slice [:a :b :c :d] -1 -2)  # => ()
(slice [:a :b :c :d] -1 -5)  # => ()

(zipcoll [:a :b :c] [1 2 3])  #=> @{:c 3 :a 1 :b 2}

(var a nil)

(var b nil)

(varfn a
  [x]
  (if (zero? x)
    0
    (b x)))
    
(varfn b
  [y]
  (if (pos? y)
    1
    (a y)))
    
(a 1)
# =>
1

(b 0)
# =>
0