Thanks a lot. It's very interesting. I always appreciate articles/tutorials
for beginners.
On Wed, Sep 26, 2018, 5:59 AM Joh-Tob Schäg <johtob...@gmail.com> wrote:
> Since there is some much stir around the presentation made by mtsd. (Great
> work by the way) I decided it is a good time to put my lightning talk at
> FrosCon out there.
> Attached is the original version i gave.
> Inline is an updated version with more content which could function as a
> PicoLisp tutorial or something.
>
> : "PicoLisp" # Hello today i want to talk a bit PicoLisp.
> -> "PicoLisp"
> : (* 2 1) #In PicoLisp you can multiply.
> -> 2
> : (* 3 (* 2 1)) # You can combine use the return values to make more
> complicated expressions.
> -> 6
> : (* 4 (* 3 (* 2 1)))
> -> 24
> : (** 2 (* 5 (* 4 (* 3 (* 2 1))))) # Numbers in PicoLisp are Integers and
> they can be as big as you RAM can handle.
> -> 1329227995784915872903807060280344576
> : (* 5 4 3 2 1) # Some functions in Picolisp take an arbitrary number of
> arguements.
> -> 120
> : (range 1 12) # And of course there are cleverer ways to generale lists
> -> (1 2 3 4 5 6 7 8 9 10 11 12)
> : (apply * (range 1 6)) # Here we use the multiply function on the list we
> generated with 'range
> -> 720
> : (de fak (N) (apply * (range 1 N))) # Let's define a function
> -> fak
> : (mapcar fak (range 1 12)) # Let's test the function by applying to the
> number 1 to 12
> -> (1 2 6 24 120 720 5040 40320 362880 3628800 39916800 479001600)
> : fak # But what is 'fal , really?
> -> ((N) (apply * (range 1 N)))
> : ('((N) (apply * (range 1 N))) 8) # It is a list in RAM and the list can
> be executed on it's own.
> -> 40320
> :(replace fak '(N) '(m)) #This means we can also modify function as f they
> are lists
> -> ((m) (apply * (range 1 N))) # Truth be told they are actually trees
> : (de treeplace (List Old New) # Define a function
> which replaces symbols on a tree
> (mapcar #For each member of the
> list in which Old was Replaced by New
> '((X) (if (lst? X) (treeplace X Old New) X)) # Recure on all lists
> you see
> (replace List Old New)))
> -> treeplace
> : fak
> -> ((N) (apply * (range 1 N))) # This is was fak looked like
> : (treeplace fak 1 2) # Multiplying by one is useless
> -> ((N) (apply * (range 2 N))) # Tada, we optimed our code
> : fak # What is the 'fak now
> -> ((N) (apply * (range 1 N))) # Fak has not change since i used
> non-destructive operations and did not give 'fak the value
> : treeplace
> -> ((List Old New) (mapcar '((X) (if (lst? X) (treeplace X Old New) X))
> (replace List Old New))) # The code is not really clear. X is not very
> descriptive.
> : (setq treeplace (treeplace treeplace 'X 'Sub)) # Since we are working
> with a sub-expression or sub-tree let's call it that.
> -> ((List Old New) (mapcar '((Sub) (if (lst? Sub) (treeplace Sub Old New)
> Sub)) (replace List Old New)))
> : treeplace # Setq sets the Symbols value
> -> ((List Old New) (mapcar '((Sub) (if (lst? Sub) (treeplace Sub Old New)
> Sub)) (replace List Old New))) # See it is way more clear what the code
> does now.
>
> Sincerely Johann-Tobias Schäg
>
