/ :`i$"A"; // 65
/ :`i$"Z"; // 90
/ :`i$"0"; // 48
/ :`i$"9"; // 57
/ :`i$":"; // 58
/ :`i$"$"; // 36

testAtZ: { i:`i$x; $[(i>64) & (i<91);1;0] };
test0t9: { i:`i$x; $[(i>47) & (i<58);1;0] };
testcol: { i:`i$x; $[i=58;1;0] };
testend: { i:`i$x; $[i=36;1;0] };

s0: ((testAtZ; 1);(test0t9; 2));
s1: ((test0t9; 2);(testcol; 3));
s2: ((testend; 7); (testcol;5));
s3: (,(testAtZ; 5));
s4: ((testAtZ; 5); (test0t9; 6));
s5: (,(testend; 7));
s6: (,(testend; 7));
s7: (({`0:"SUCCESS"};7));
// 7 is done
states:: (s0;s1;s2;s3;s4;s5;s6;s7);
i: 1;

run: {[str] str,:"$"; `0:str; s: 0; :o:s {[s;c] r:{t: x[0][y]; o:$[t;x[1];0]; o}[;c]'states[s]; `0:`k@(s;c;ns); ns:states@(&r); ns}\str;};

// todo: don't be using $
// prepare for matching pattern and returning the start index and length
test: "A:A";
run[test]