53 lines
2.5 KiB
Plaintext
53 lines
2.5 KiB
Plaintext
|
|
(load-file "./k_prime_stdlib/prelude.kp")
|
|
|
|
; We don't have atoms built in, mutable arrays
|
|
; are our base building block. In order to make the
|
|
; following BF implementation nice, let's add atoms!
|
|
; They will be implmented as length 1 arrays with nice syntax for deref
|
|
(fun make-atom (x) [x])
|
|
(fun set-atom! (x y) (set-idx! x 0 y))
|
|
(fun get-atom (x) (idx x 0))
|
|
(add_grammar_rule 'form ["@" 'form] (lambda (_ x) `(get-atom ~x)))
|
|
|
|
; Now begin by defining our BF syntax & semantics
|
|
; Define our tokens as BF atoms
|
|
(add_grammar_rule 'bfs_atom ["<"] (lambda (_) '(set-atom! cursor (- @cursor 1))))
|
|
(add_grammar_rule 'bfs_atom [">"] (lambda (_) '(set-atom! cursor (+ @cursor 1))))
|
|
(add_grammar_rule 'bfs_atom ["\\+"] (lambda (_) '(set-idx! tape @cursor (+ (idx tape @cursor) 1))))
|
|
(add_grammar_rule 'bfs_atom ["-"] (lambda (_) '(set-idx! tape @cursor (- (idx tape @cursor) 1))))
|
|
(add_grammar_rule 'bfs_atom [","] (lambda (_) '(let (value (idx input @inptr))
|
|
(do (set-atom! inptr (+ 1 @inptr))
|
|
(set-idx! tape @cursor value)))))
|
|
(add_grammar_rule 'bfs_atom ["."] (lambda (_) '(set-atom! output (concat [(idx tape @cursor)] @output))))
|
|
|
|
; Define strings of BF atoms
|
|
(add_grammar_rule 'bfs ['bfs_atom *] (lambda (x) x))
|
|
|
|
; Add loop as an atom
|
|
; (note that closure cannot yet close over itself by value, so we pass it in)
|
|
(add_grammar_rule 'bfs_atom ["\\[" 'bfs "]"] (lambda (_ x _)
|
|
`(let (f (lambda (f)
|
|
(if (= 0 (idx tape @cursor))
|
|
nil
|
|
(do ,x (f f)))))
|
|
(f f))))
|
|
|
|
; For now, stick BFS rule inside an unambigious BFS block
|
|
; Also add setup code
|
|
(add_grammar_rule 'form ["bf" 'optional_WS "{" 'optional_WS 'bfs 'optional_WS "}"]
|
|
(lambda (_ _ _ _ x _ _)
|
|
`(lambda (input)
|
|
(let (
|
|
tape (array 0 0 0 0 0)
|
|
cursor (make-atom 0)
|
|
inptr (make-atom 0)
|
|
output (make-atom (array))
|
|
)
|
|
(do (println "beginning bfs") ,x (idx output 0))))))
|
|
|
|
; Let's try it out! This BF program prints the input 3 times
|
|
(println (bf { ,>+++[<.>-] } [1337]))
|
|
; we can also have it compile into our main program
|
|
(fun main () (do (println "BF: " (bf { ,>+++[<.>-] } [1337])) 0))
|