This is a (naive) brainfuck implementation written in Common Lisp.
This implementation is a nice implementation:
- It uses 30,000 cells.
- If a program attempts to move beyond the bounds of those 30,000 cells, it will raise an error.
- The cell values are of type
'(unsigned-byte 8). - If a program attempts to increment the value of a cell above the maximum, or decrement a value below the minimum, it will wrap around.
- If a program contains unbalanced brackets, an error will be raised.
When EOF is read, the cell at the pointer is set to 0 (as opposed to the other popular options of -1 or "no change").
(bf-eval state)
For example, at the REPL,
BRAINFUCK> (defparameter *hello-world* "++++++++++[>+++++++>++++++++++>
+++>+<<<<-]>++.>+.+++++++..+++.>++.<<+++
++++++++++++.>.+++.------.--------.>+.>.")
*HELLO-WORLD*
BRAINFUCK> (bf-eval (make-bf-state :program *hello-world*))
Hello World!
NIL
(bf-repl)
(bf-repl) will start a REPL where you can enter brainfuck programs.
Entered programs must be on a single line.
(bf-body program in out)
bf-body is really a helper function for bf-compile below, but it
us useful for testing. It returns the s-expression that is created
from the brainfuck program.
For example:
(bf-body *hello-world* *standard-input* *standard-output*)
(bf-compile program &key (in *standard-input*) (out *standard-output*))
Returns a compiled function. For example:
* (funcall (bf-compile *hello-world*))
Hello, World!
(bf-compile-file path &key (in *standard-input*) (out *standard-output*))
Returns a compiled function. For example:
* (bf-compile-file #p"bf/hello-world.lisp")
Hello, world!
On Win8 x64, the windows fork of sbcl requires a lot of time and memory to compile 99-bottles.bf:
$ sbcl --dynamic-space-size 2048
This is SBCL 1.1.4.0.mswin.1288-90ab477, an implementation of ANSI Common Lisp.
* (bf-compile-file #p"bf/99-bottles.bf") ;; bf-compile-file calls
;; (time) internally.
Evaluation took:
16.207 seconds of real time
16.171875 seconds of total run time (13.875000 user, 2.296875 system)
[ Run times consist of 6.179 seconds GC time, and 9.993 seconds non-GC time. ]
99.78% CPU
23,617 lambdas converted
38,808,919,242 processor cycles
2,837,170,720 bytes consed
Whereas ccl has no problems.
$ ccl
Welcome to Clozure Common Lisp Version 1.9-r15765 (WindowsX8664)!
* (bf-compile-file #p"bf/99-bottles.bf") ;; bf-compile-file calls
;; (time) internally.
(COMPILE NIL (BF-BODY PROGRAM IN OUT))
took 1,814,000 microseconds (1.814000 seconds) to run.
143,096 microseconds (0.143096 seconds, 7.89%) of which was spent in GC.
During that period, and with 8 available CPU cores,
1,796,875 microseconds (1.796875 seconds) were spent in user mode
15,625 microseconds (0.015625 seconds) were spent in system mode
48,043,200 bytes of memory allocated.
MIT