Crunches BF programs of the form
{...s2}<{s1}<{s0}[{k0}[<{j0}>{j1}>{c0}>{c1}>{c2...}<<<]{h}>{k1}]
of the given length. Programs of this form fill the tape with simple recurrence relations.
The shortest useful program of this type has length 14:
+[[<+>->++<]>]
which computes the powers of 2 as fn = 2*fn-1, f0 = 1
Usage: bfcrunch [--options] text [limit]
Crunches BF programs to produce a given text.
Arguments
------------------------------------------------------------
text The text to produce.
limit The maximum BF program length to search for. If empty, the length of the
shortest program found so far will be used (-r). Default = (empty)
Options
------------------------------------------------------------
-i, --max-init=# The maximum length of the initialization segment. If empty, the program
will run indefinitely. Default = (empty)
-I, --min-init=# The minimum length of the initialization segment. Default = 14
-t, --max-tape=# The maximum tape size to consider. Programs that utilize more tape than
this will be ignored. Default = 1250
-T, --min-tape=# The minimum tape size to consider. Programs that utilize less tape than
this will be ignored. Default = 1
-n, --max-node-cost=#
The maximum cost for any node. Default = 20
-l, --max-loops=#
The maximum number of iterations of the main loop. Default = 30000
-s, --max-slen=# The maximum length of the s-segment. Default = (empty)
-S, --min-slen=# The minimum length of the s-segment. Default = 1
-c, --max-clen=# The maximum length of the c-segment. Default = (empty)
-C, --min-clen=# The minimum length of the c-segment. Default = 1
-r, --rolling-limit
If set, the limit will be adjusted whenever a shorter program is found.
-u, --unique-cells
If set, each used cell used for output will be unique.
-?, --help Display this help text.
Output is given in three lines:
- Total length of the program found, and the initialization segment.
- Path taken, starting with the current tape pointer. Each node corresponds to one character of output, represented as (pointer, cost).
- Utilized tape segment.
For example, the final result for bfcrunch "hello world" 70 -r -i23 is:
64: ++++[[<+>->+++++>+<<]>]
49, (45, 5), (44, 3), (45, 6), (45, 1), (45, 4), (42, 4), (43, 5), (45, 3), (45, 4), (46, 2), (44, 4)
32, 116, 100, 104, 108, 132, 0, 0, 132, 0
This corresponds to the full program:
++++[[<+>->+++++>+<<]>]<<<<.<+.>++++..+++.<<<.>+++.>>.+++.>.<<-.