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* Fennel Cljlib
Library for [[https://fennel-lang.org/][Fennel]] language that adds a lot of functions from [[https://clojure.org/][Clojure]] standard library.
This is not a one to one port of Clojure =core=, because many Clojure functions require certain guarantees, like immutability of the underlying data structures.
Therefore some names were changed, but they should be still recognizable.
Goals of this project are:
- Have a self contained library, with no dependencies, that provides a set of useful functions from Clojure =core=,
- Be close to the platform, e.g. implement functions in a way that is efficient to use in Lua VM,
- Be well documented library, with good test coverage.
** Functions
Here are some important functions from the library.
Full set can be examined by requiring the module.
*** =mapv= and =mapkv=
Mapping functions.
In Clojure we have a =seq= abstraction, that allows us to use single =mapv= on both vectors, and hash tables.
However in Fennel, and Lua there's no efficient way of checking if we got an associative or indexed table.
For this reason, there are two functions - =mapv=, or which maps over vectors, and =mapkv= which maps over associative tables (=kv= is for key-value).
Here, =mapv= works the same as =mapv= from Clojure, except it doesn't yield a transducer (yet?) when only function is supplied.
=mapkv= also works similarly, except it requires for function you pass to accept twice the amount of tables you pass to =mapkv=.
#+begin_src fennel
(fn cube [x] (* x x x))
(mapv cube [1 2 3])
;; [1 8 27]
(mapv #(* $1 $2) [1 2 3] [1 -1 0])
;; [1 -2 0]
(mapv (fn [f-name s-name company position]
(.. f-name " " s-name " works as " position " at " company))
["Bob" "Alice"]
["Smith" "Watson"]
["Happy Days co." "Coffee With You"]
["secretary" "chief officer"])
;; ["Bob Smith works as secretary at Happy Days co."
;; "Alice Watson works as chief officer at Coffee With You"]
(mapkv (fn [k v] [k v]) {:host "localhost" :port 1344})
;; [["port" 1344] ["host" "localhost"]]
#+end_src
*** =reduce= and =reduce-kv=
Ordinary reducing functions.
Work the same as in Clojure, except doesn't yield transducer when only function was passed.
#+begin_src fennel
(fn add [a b] (+ a b))
(reduce add [1 2 3 4 5]) ;; 15
(reduce add 10 [1 2 3 4 5]) ;; 25
#+end_src
# LocalWords: Luajit VM
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