77 lines
2.1 KiB
Nim
77 lines
2.1 KiB
Nim
import strutils, tables
|
|
|
|
proc runUTM(state, halt, blank: string, tape: seq[string] = @[],
|
|
rules: seq[seq[string]]) =
|
|
var
|
|
st = state
|
|
pos = 0
|
|
tape = tape
|
|
rulesTable = initTable[tuple[s0, v0: string], tuple[v1, dr, s1: string]]()
|
|
|
|
if tape.len == 0: tape = @[blank]
|
|
if pos < 0: pos += tape.len
|
|
assert pos in 0..tape.high
|
|
|
|
for r in rules:
|
|
assert r.len == 5
|
|
rulesTable[(r[0], r[1])] = (r[2], r[3], r[4])
|
|
|
|
while true:
|
|
stdout.write st,'\t'
|
|
for i, v in tape:
|
|
if i == pos: stdout.write '[',v,']'
|
|
else: stdout.write ' ',v,' '
|
|
echo ""
|
|
|
|
if st == halt: break
|
|
if not rulesTable.hasKey((st, tape[pos])): break
|
|
|
|
let (v1, dr, s1) = rulesTable[(st, tape[pos])]
|
|
tape[pos] = v1
|
|
if dr == "left":
|
|
if pos > 0: dec pos
|
|
else: tape.insert blank
|
|
if dr == "right":
|
|
inc pos
|
|
if pos >= tape.len: tape.add blank
|
|
st = s1
|
|
|
|
echo "incr machine\n"
|
|
runUTM(halt = "qf",
|
|
state = "q0",
|
|
tape = "1 1 1".split,
|
|
blank = "B",
|
|
rules = @["q0 1 1 right q0".split,
|
|
"q0 B 1 stay qf".split])
|
|
|
|
echo "\nbusy beaver\n"
|
|
runUTM(halt = "halt",
|
|
state = "a",
|
|
blank = "0",
|
|
rules = @["a 0 1 right b".split,
|
|
"a 1 1 left c".split,
|
|
"b 0 1 left a".split,
|
|
"b 1 1 right b".split,
|
|
"c 0 1 left b".split,
|
|
"c 1 1 stay halt".split])
|
|
|
|
echo "\nsorting test\n"
|
|
runUTM(halt = "STOP",
|
|
state = "A",
|
|
blank = "0",
|
|
tape = "2 2 2 1 2 2 1 2 1 2 1 2 1 2".split,
|
|
rules = @["A 1 1 right A".split,
|
|
"A 2 3 right B".split,
|
|
"A 0 0 left E".split,
|
|
"B 1 1 right B".split,
|
|
"B 2 2 right B".split,
|
|
"B 0 0 left C".split,
|
|
"C 1 2 left D".split,
|
|
"C 2 2 left C".split,
|
|
"C 3 2 left E".split,
|
|
"D 1 1 left D".split,
|
|
"D 2 2 left D".split,
|
|
"D 3 1 right A".split,
|
|
"E 1 1 left E".split,
|
|
"E 0 0 right STOP".split])
|