Community documentation for Janet

math/e 
# => 2.71828

# Gathers all of the calls of "declare-" into a table from the project.janet file at path
(defn capture-declares [path] 
    (def *capture* @{})
    (defn append-capture [name & arg]
      (update *capture* name (fn [val] (array/push (or val @[]) ;arg))))
    (defn only-captures [form] 
      (when (string/has-prefix? "declare-" (string (form 0)))
        (append-capture (form 0) (slice form 1))
        form)
      nil)
    (dofile path :expander only-captures)
    *capture*)

(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   ]

(describe {:a 1}) # => "<struct 0x5564AF1BD6C0>"

(filter (fn [x] (> x 2)) [1 2 3 4 5])  # @[3 4 5]

$ # trivial server which echo's to the console.
$ cat > srv.janet << EOF
#!/usr/bin/env janet

(defn handle-conn [conn]
  (print "new connection")
  (while true
    (def data (net/read conn 4096))
    (if (not data) (break))
    (prin data))
  (net/close conn)
  (print "connection closed"))

(print "starting server on 0.0.0.0:1234")
(net/server "0.0.0.0" 1234 handle-conn)
EOF
$ chmod +x srv.janet
$ ./srv.janet

----

$ # in another terminal:
$ echo hello | nc 0.0.0.0 1234

(peg/find-all ':d "hi 1 bye 2") # => @[3 9]

(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

(peg/find-all ~(capture (range "09"))
              "hi 0 bye 1")
# => @[3 9]

(* 2 3)      # -> 6
(* 2 3.3)    # -> 6.6
(* 2.2 3.3)  # -> 7.26

(def pi 3.14159)
(* 2 pi)  # -> 6.28318

(* 2)  # -> 2
(*)    # -> 1

(* 2 3 4)             # -> 24
(apply * [2 3 4])     # -> 24
(* (splice [2 3 4]))  # -> 24
(* ;[2 3 4])          # -> 24
(def a [2 3 4])
(* ;a)                # -> 24

(last "hello")
# => 111

(from-pairs [[:hello "world"] [:foo "bar"]]) 

# => @{:foo "bar" :hello "world"}

(def kvpairs [[:x 1] [:y 2]])

(table ;(flatten kvpairs)) # => @{:x 1 :y 2}

(os/sleep 1)    # => nil
(os/sleep 0.1)  # => nil
(os/sleep 0)    # => nil

(table/new 2)
# => @{}