void strIter(SV* code, SV* string)  {
    dSP;
    STRLEN i;
    char* src = SvPV(string, i);
    SV* c;

    c = newSV_type(SVt_PV);
    SvCUR(c) = 1;
    SvLEN(c) = 0;
    SvPOK_only(c);

    SAVE_DEFSV;
    DEFSV_set(c);

    while (i--) {
        SvPVX(c) = src++;
        PUSHMARK(SP);
        call_sv(code, G_NOARGS | G_VOID | G_DISCARD);
    }
}