'use client';
// it's like "peek", but need for look-ahead or look-behind if index < 0
function look(stream, c){
  return stream.string.charAt(stream.pos+(c||0));
}

// return a part of prefix of current stream from current position
function prefix(stream, c){
  if(c){
    var x=stream.pos-c;
    return stream.string.substr((x>=0?x:0),c);}
  else {
    return stream.string.substr(0,stream.pos-1);
  }
}

// return a part of suffix of current stream from current position
function suffix(stream, c){
  var y=stream.string.length;
  var x=y-stream.pos+1;
  return stream.string.substr(stream.pos,(c&&c<y?c:x));
}

// eating and vomiting a part of stream from current position
function eatSuffix(stream, c){
  var x=stream.pos+c;
  var y;
  if(x<=0)
    stream.pos=0;
  else if(x>=(y=stream.string.length-1))
    stream.pos=y;
  else
    stream.pos=x;
}

// http://perldoc.perl.org
var PERL={                                      //   null - magic touch
  //   1 - keyword
  //   2 - def
  //   3 - atom
  //   4 - operator
  //   5 - builtin (predefined)
  //   [x,y] - x=1,2,3; y=must be defined if x{...}
  //      PERL operators
  '->':   4,
  '++':   4,
  '--':   4,
  '**':   4,
  //   ! ~ \ and unary + and -
  '=~':   4,
  '!~':   4,
  '*':   4,
  '/':   4,
  '%':   4,
  'x':   4,
  '+':   4,
  '-':   4,
  '.':   4,
  '<<':   4,
  '>>':   4,
  //   named unary operators
  '<':   4,
  '>':   4,
  '<=':   4,
  '>=':   4,
  'lt':   4,
  'gt':   4,
  'le':   4,
  'ge':   4,
  '==':   4,
  '!=':   4,
  '<=>':   4,
  'eq':   4,
  'ne':   4,
  'cmp':   4,
  '~~':   4,
  '&':   4,
  '|':   4,
  '^':   4,
  '&&':   4,
  '||':   4,
  '//':   4,
  '..':   4,
  '...':   4,
  '?':   4,
  ':':   4,
  '=':   4,
  '+=':   4,
  '-=':   4,
  '*=':   4,  //   etc. ???
  ',':   4,
  '=>':   4,
  '::':   4,
  //   list operators (rightward)
  'not':   4,
  'and':   4,
  'or':   4,
  'xor':   4,
  //      PERL predefined variables (I know, what this is a paranoid idea, but may be needed for people, who learn PERL, and for me as well, ...and may be for you?;)
  'BEGIN':   [5,1],
  'END':   [5,1],
  'PRINT':   [5,1],
  'PRINTF':   [5,1],
  'GETC':   [5,1],
  'READ':   [5,1],
  'READLINE':   [5,1],
  'DESTROY':   [5,1],
  'TIE':   [5,1],
  'TIEHANDLE':   [5,1],
  'UNTIE':   [5,1],
  'STDIN':    5,
  'STDIN_TOP':    5,
  'STDOUT':    5,
  'STDOUT_TOP':    5,
  'STDERR':    5,
  'STDERR_TOP':    5,
  '$ARG':    5,
  '$_':    5,
  '@ARG':    5,
  '@_':    5,
  '$LIST_SEPARATOR':    5,
  '$"':    5,
  '$PROCESS_ID':    5,
  '$PID':    5,
  '$$':    5,
  '$REAL_GROUP_ID':    5,
  '$GID':    5,
  '$(':    5,
  '$EFFECTIVE_GROUP_ID':    5,
  '$EGID':    5,
  '$)':    5,
  '$PROGRAM_NAME':    5,
  '$0':    5,
  '$SUBSCRIPT_SEPARATOR':    5,
  '$SUBSEP':    5,
  '$;':    5,
  '$REAL_USER_ID':    5,
  '$UID':    5,
  '$<':    5,
  '$EFFECTIVE_USER_ID':    5,
  '$EUID':    5,
  '$>':    5,
  '$a':    5,
  '$b':    5,
  '$COMPILING':    5,
  '$^C':    5,
  '$DEBUGGING':    5,
  '$^D':    5,
  '${^ENCODING}':    5,
  '$ENV':    5,
  '%ENV':    5,
  '$SYSTEM_FD_MAX':    5,
  '$^F':    5,
  '@F':    5,
  '${^GLOBAL_PHASE}':    5,
  '$^H':    5,
  '%^H':    5,
  '@INC':    5,
  '%INC':    5,
  '$INPLACE_EDIT':    5,
  '$^I':    5,
  '$^M':    5,
  '$OSNAME':    5,
  '$^O':    5,
  '${^OPEN}':    5,
  '$PERLDB':    5,
  '$^P':    5,
  '$SIG':    5,
  '%SIG':    5,
  '$BASETIME':    5,
  '$^T':    5,
  '${^TAINT}':    5,
  '${^UNICODE}':    5,
  '${^UTF8CACHE}':    5,
  '${^UTF8LOCALE}':    5,
  '$PERL_VERSION':    5,
  '$^V':    5,
  '${^WIN32_SLOPPY_STAT}':    5,
  '$EXECUTABLE_NAME':    5,
  '$^X':    5,
  '$1':    5, // - regexp $1, $2...
  '$MATCH':    5,
  '$&':    5,
  '${^MATCH}':    5,
  '$PREMATCH':    5,
  '$`':    5,
  '${^PREMATCH}':    5,
  '$POSTMATCH':    5,
  "$'":    5,
  '${^POSTMATCH}':    5,
  '$LAST_PAREN_MATCH':    5,
  '$+':    5,
  '$LAST_SUBMATCH_RESULT':    5,
  '$^N':    5,
  '@LAST_MATCH_END':    5,
  '@+':    5,
  '%LAST_PAREN_MATCH':    5,
  '%+':    5,
  '@LAST_MATCH_START':    5,
  '@-':    5,
  '%LAST_MATCH_START':    5,
  '%-':    5,
  '$LAST_REGEXP_CODE_RESULT':    5,
  '$^R':    5,
  '${^RE_DEBUG_FLAGS}':    5,
  '${^RE_TRIE_MAXBUF}':    5,
  '$ARGV':    5,
  '@ARGV':    5,
  'ARGV':    5,
  'ARGVOUT':    5,
  '$OUTPUT_FIELD_SEPARATOR':    5,
  '$OFS':    5,
  '$,':    5,
  '$INPUT_LINE_NUMBER':    5,
  '$NR':    5,
  '$.':    5,
  '$INPUT_RECORD_SEPARATOR':    5,
  '$RS':    5,
  '$/':    5,
  '$OUTPUT_RECORD_SEPARATOR':    5,
  '$ORS':    5,
  '$\\':    5,
  '$OUTPUT_AUTOFLUSH':    5,
  '$|':    5,
  '$ACCUMULATOR':    5,
  '$^A':    5,
  '$FORMAT_FORMFEED':    5,
  '$^L':    5,
  '$FORMAT_PAGE_NUMBER':    5,
  '$%':    5,
  '$FORMAT_LINES_LEFT':    5,
  '$-':    5,
  '$FORMAT_LINE_BREAK_CHARACTERS':    5,
  '$:':    5,
  '$FORMAT_LINES_PER_PAGE':    5,
  '$=':    5,
  '$FORMAT_TOP_NAME':    5,
  '$^':    5,
  '$FORMAT_NAME':    5,
  '$~':    5,
  '${^CHILD_ERROR_NATIVE}':    5,
  '$EXTENDED_OS_ERROR':    5,
  '$^E':    5,
  '$EXCEPTIONS_BEING_CAUGHT':    5,
  '$^S':    5,
  '$WARNING':    5,
  '$^W':    5,
  '${^WARNING_BITS}':    5,
  '$OS_ERROR':    5,
  '$ERRNO':    5,
  '$!':    5,
  '%OS_ERROR':    5,
  '%ERRNO':    5,
  '%!':    5,
  '$CHILD_ERROR':    5,
  '$?':    5,
  '$EVAL_ERROR':    5,
  '$@':    5,
  '$OFMT':    5,
  '$#':    5,
  '$*':    5,
  '$ARRAY_BASE':    5,
  '$[':    5,
  '$OLD_PERL_VERSION':    5,
  '$]':    5,
  //      PERL blocks
  'if':[1,1],
  elsif:[1,1],
  'else':[1,1],
  'while':[1,1],
  unless:[1,1],
  'for':[1,1],
  foreach:[1,1],
  //      PERL functions
  'abs':1,     // - absolute value function
  accept:1,     // - accept an incoming socket connect
  alarm:1,     // - schedule a SIGALRM
  'atan2':1,     // - arctangent of Y/X in the range -PI to PI
  bind:1,     // - binds an address to a socket
  binmode:1,     // - prepare binary files for I/O
  bless:1,     // - create an object
  bootstrap:1,     //
  'break':1,     // - break out of a "given" block
  caller:1,     // - get context of the current subroutine call
  chdir:1,     // - change your current working directory
  chmod:1,     // - changes the permissions on a list of files
  chomp:1,     // - remove a trailing record separator from a string
  chop:1,     // - remove the last character from a string
  chown:1,     // - change the ownership on a list of files
  chr:1,     // - get character this number represents
  chroot:1,     // - make directory new root for path lookups
  close:1,     // - close file (or pipe or socket) handle
  closedir:1,     // - close directory handle
  connect:1,     // - connect to a remote socket
  'continue':[1,1], // - optional trailing block in a while or foreach
  'cos':1,     // - cosine function
  crypt:1,     // - one-way passwd-style encryption
  dbmclose:1,     // - breaks binding on a tied dbm file
  dbmopen:1,     // - create binding on a tied dbm file
  'default':1,     //
  defined:1,     // - test whether a value, variable, or function is defined
  'delete':1,     // - deletes a value from a hash
  die:1,     // - raise an exception or bail out
  'do':1,     // - turn a BLOCK into a TERM
  dump:1,     // - create an immediate core dump
  each:1,     // - retrieve the next key/value pair from a hash
  endgrent:1,     // - be done using group file
  endhostent:1,     // - be done using hosts file
  endnetent:1,     // - be done using networks file
  endprotoent:1,     // - be done using protocols file
  endpwent:1,     // - be done using passwd file
  endservent:1,     // - be done using services file
  eof:1,     // - test a filehandle for its end
  'eval':1,     // - catch exceptions or compile and run code
  'exec':1,     // - abandon this program to run another
  exists:1,     // - test whether a hash key is present
  exit:1,     // - terminate this program
  'exp':1,     // - raise I to a power
  fcntl:1,     // - file control system call
  fileno:1,     // - return file descriptor from filehandle
  flock:1,     // - lock an entire file with an advisory lock
  fork:1,     // - create a new process just like this one
  format:1,     // - declare a picture format with use by the write() function
  formline:1,     // - internal function used for formats
  getc:1,     // - get the next character from the filehandle
  getgrent:1,     // - get next group record
  getgrgid:1,     // - get group record given group user ID
  getgrnam:1,     // - get group record given group name
  gethostbyaddr:1,     // - get host record given its address
  gethostbyname:1,     // - get host record given name
  gethostent:1,     // - get next hosts record
  getlogin:1,     // - return who logged in at this tty
  getnetbyaddr:1,     // - get network record given its address
  getnetbyname:1,     // - get networks record given name
  getnetent:1,     // - get next networks record
  getpeername:1,     // - find the other end of a socket connection
  getpgrp:1,     // - get process group
  getppid:1,     // - get parent process ID
  getpriority:1,     // - get current nice value
  getprotobyname:1,     // - get protocol record given name
  getprotobynumber:1,     // - get protocol record numeric protocol
  getprotoent:1,     // - get next protocols record
  getpwent:1,     // - get next passwd record
  getpwnam:1,     // - get passwd record given user login name
  getpwuid:1,     // - get passwd record given user ID
  getservbyname:1,     // - get services record given its name
  getservbyport:1,     // - get services record given numeric port
  getservent:1,     // - get next services record
  getsockname:1,     // - retrieve the sockaddr for a given socket
  getsockopt:1,     // - get socket options on a given socket
  given:1,     //
  glob:1,     // - expand filenames using wildcards
  gmtime:1,     // - convert UNIX time into record or string using Greenwich time
  'goto':1,     // - create spaghetti code
  grep:1,     // - locate elements in a list test true against a given criterion
  hex:1,     // - convert a string to a hexadecimal number
  'import':1,     // - patch a module's namespace into your own
  index:1,     // - find a substring within a string
  'int':1,     // - get the integer portion of a number
  ioctl:1,     // - system-dependent device control system call
  'join':1,     // - join a list into a string using a separator
  keys:1,     // - retrieve list of indices from a hash
  kill:1,     // - send a signal to a process or process group
  last:1,     // - exit a block prematurely
  lc:1,     // - return lower-case version of a string
  lcfirst:1,     // - return a string with just the next letter in lower case
  length:1,     // - return the number of bytes in a string
  'link':1,     // - create a hard link in the filesystem
  listen:1,     // - register your socket as a server
  local: 2,    // - create a temporary value for a global variable (dynamic scoping)
  localtime:1,     // - convert UNIX time into record or string using local time
  lock:1,     // - get a thread lock on a variable, subroutine, or method
  'log':1,     // - retrieve the natural logarithm for a number
  lstat:1,     // - stat a symbolic link
  m:null,  // - match a string with a regular expression pattern
  map:1,     // - apply a change to a list to get back a new list with the changes
  mkdir:1,     // - create a directory
  msgctl:1,     // - SysV IPC message control operations
  msgget:1,     // - get SysV IPC message queue
  msgrcv:1,     // - receive a SysV IPC message from a message queue
  msgsnd:1,     // - send a SysV IPC message to a message queue
  my: 2,    // - declare and assign a local variable (lexical scoping)
  'new':1,     //
  next:1,     // - iterate a block prematurely
  no:1,     // - unimport some module symbols or semantics at compile time
  oct:1,     // - convert a string to an octal number
  open:1,     // - open a file, pipe, or descriptor
  opendir:1,     // - open a directory
  ord:1,     // - find a character's numeric representation
  our: 2,    // - declare and assign a package variable (lexical scoping)
  pack:1,     // - convert a list into a binary representation
  'package':1,     // - declare a separate global namespace
  pipe:1,     // - open a pair of connected filehandles
  pop:1,     // - remove the last element from an array and return it
  pos:1,     // - find or set the offset for the last/next m//g search
  print:1,     // - output a list to a filehandle
  printf:1,     // - output a formatted list to a filehandle
  prototype:1,     // - get the prototype (if any) of a subroutine
  push:1,     // - append one or more elements to an array
  q:null,  // - singly quote a string
  qq:null,  // - doubly quote a string
  qr:null,  // - Compile pattern
  quotemeta:null,  // - quote regular expression magic characters
  qw:null,  // - quote a list of words
  qx:null,  // - backquote quote a string
  rand:1,     // - retrieve the next pseudorandom number
  read:1,     // - fixed-length buffered input from a filehandle
  readdir:1,     // - get a directory from a directory handle
  readline:1,     // - fetch a record from a file
  readlink:1,     // - determine where a symbolic link is pointing
  readpipe:1,     // - execute a system command and collect standard output
  recv:1,     // - receive a message over a Socket
  redo:1,     // - start this loop iteration over again
  ref:1,     // - find out the type of thing being referenced
  rename:1,     // - change a filename
  require:1,     // - load in external functions from a library at runtime
  reset:1,     // - clear all variables of a given name
  'return':1,     // - get out of a function early
  reverse:1,     // - flip a string or a list
  rewinddir:1,     // - reset directory handle
  rindex:1,     // - right-to-left substring search
  rmdir:1,     // - remove a directory
  s:null,  // - replace a pattern with a string
  say:1,     // - print with newline
  scalar:1,     // - force a scalar context
  seek:1,     // - reposition file pointer for random-access I/O
  seekdir:1,     // - reposition directory pointer
  select:1,     // - reset default output or do I/O multiplexing
  semctl:1,     // - SysV semaphore control operations
  semget:1,     // - get set of SysV semaphores
  semop:1,     // - SysV semaphore operations
  send:1,     // - send a message over a socket
  setgrent:1,     // - prepare group file for use
  sethostent:1,     // - prepare hosts file for use
  setnetent:1,     // - prepare networks file for use
  setpgrp:1,     // - set the process group of a process
  setpriority:1,     // - set a process's nice value
  setprotoent:1,     // - prepare protocols file for use
  setpwent:1,     // - prepare passwd file for use
  setservent:1,     // - prepare services file for use
  setsockopt:1,     // - set some socket options
  shift:1,     // - remove the first element of an array, and return it
  shmctl:1,     // - SysV shared memory operations
  shmget:1,     // - get SysV shared memory segment identifier
  shmread:1,     // - read SysV shared memory
  shmwrite:1,     // - write SysV shared memory
  shutdown:1,     // - close down just half of a socket connection
  'sin':1,     // - return the sine of a number
  sleep:1,     // - block for some number of seconds
  socket:1,     // - create a socket
  socketpair:1,     // - create a pair of sockets
  'sort':1,     // - sort a list of values
  splice:1,     // - add or remove elements anywhere in an array
  'split':1,     // - split up a string using a regexp delimiter
  sprintf:1,     // - formatted print into a string
  'sqrt':1,     // - square root function
  srand:1,     // - seed the random number generator
  stat:1,     // - get a file's status information
  state:1,     // - declare and assign a state variable (persistent lexical scoping)
  study:1,     // - optimize input data for repeated searches
  'sub':1,     // - declare a subroutine, possibly anonymously
  'substr':1,     // - get or alter a portion of a string
  symlink:1,     // - create a symbolic link to a file
  syscall:1,     // - execute an arbitrary system call
  sysopen:1,     // - open a file, pipe, or descriptor
  sysread:1,     // - fixed-length unbuffered input from a filehandle
  sysseek:1,     // - position I/O pointer on handle used with sysread and syswrite
  system:1,     // - run a separate program
  syswrite:1,     // - fixed-length unbuffered output to a filehandle
  tell:1,     // - get current seekpointer on a filehandle
  telldir:1,     // - get current seekpointer on a directory handle
  tie:1,     // - bind a variable to an object class
  tied:1,     // - get a reference to the object underlying a tied variable
  time:1,     // - return number of seconds since 1970
  times:1,     // - return elapsed time for self and child processes
  tr:null,  // - transliterate a string
  truncate:1,     // - shorten a file
  uc:1,     // - return upper-case version of a string
  ucfirst:1,     // - return a string with just the next letter in upper case
  umask:1,     // - set file creation mode mask
  undef:1,     // - remove a variable or function definition
  unlink:1,     // - remove one link to a file
  unpack:1,     // - convert binary structure into normal perl variables
  unshift:1,     // - prepend more elements to the beginning of a list
  untie:1,     // - break a tie binding to a variable
  use:1,     // - load in a module at compile time
  utime:1,     // - set a file's last access and modify times
  values:1,     // - return a list of the values in a hash
  vec:1,     // - test or set particular bits in a string
  wait:1,     // - wait for any child process to die
  waitpid:1,     // - wait for a particular child process to die
  wantarray:1,     // - get void vs scalar vs list context of current subroutine call
  warn:1,     // - print debugging info
  when:1,     //
  write:1,     // - print a picture record
  y:null}; // - transliterate a string

var RXstyle="string.special";
var RXmodifiers=/[goseximacplud]/;              // NOTE: "m", "s", "y" and "tr" need to correct real modifiers for each regexp type

function tokenChain(stream,state,chain,style,tail){     // NOTE: chain.length > 2 is not working now (it's for s[...][...]geos;)
  state.chain=null;                               //                                                          12   3tail
  state.style=null;
  state.tail=null;
  state.tokenize=function(stream,state){
    var e=false,c,i=0;
    while(c=stream.next()){
      if(c===chain[i]&&!e){
        if(chain[++i]!==undefined){
          state.chain=chain[i];
          state.style=style;
          state.tail=tail;}
        else if(tail)
          stream.eatWhile(tail);
        state.tokenize=tokenPerl;
        return style;}
      e=!e&&c=="\\";}
    return style;};
  return state.tokenize(stream,state);}

function tokenSOMETHING(stream,state,string){
  state.tokenize=function(stream,state){
    if(stream.string==string)
      state.tokenize=tokenPerl;
    stream.skipToEnd();
    return "string";};
  return state.tokenize(stream,state);}

function tokenPerl(stream,state){
  if(stream.eatSpace())
    return null;
  if(state.chain)
    return tokenChain(stream,state,state.chain,state.style,state.tail);
  if(stream.match(/^(\-?((\d[\d_]*)?\.\d+(e[+-]?\d+)?|\d+\.\d*)|0x[\da-fA-F_]+|0b[01_]+|\d[\d_]*(e[+-]?\d+)?)/))
    return 'number';
  if(stream.match(/^<<(?=[_a-zA-Z])/)){                  // NOTE: <<SOMETHING\n...\nSOMETHING\n
    stream.eatWhile(/\w/);
    return tokenSOMETHING(stream,state,stream.current().substr(2));}
  if(stream.sol()&&stream.match(/^\=item(?!\w)/)){// NOTE: \n=item...\n=cut\n
    return tokenSOMETHING(stream,state,'=cut');}
  var ch=stream.next();
  if(ch=='"'||ch=="'"){                           // NOTE: ' or " or <<'SOMETHING'\n...\nSOMETHING\n or <<"SOMETHING"\n...\nSOMETHING\n
    if(prefix(stream, 3)=="<<"+ch){
      var p=stream.pos;
      stream.eatWhile(/\w/);
      var n=stream.current().substr(1);
      if(n&&stream.eat(ch))
        return tokenSOMETHING(stream,state,n);
      stream.pos=p;}
    return tokenChain(stream,state,[ch],"string");}
  if(ch=="q"){
    var c=look(stream, -2);
    if(!(c&&/\w/.test(c))){
      c=look(stream, 0);
      if(c=="x"){
        c=look(stream, 1);
        if(c=="("){
          eatSuffix(stream, 2);
          return tokenChain(stream,state,[")"],RXstyle,RXmodifiers);}
        if(c=="["){
          eatSuffix(stream, 2);
          return tokenChain(stream,state,["]"],RXstyle,RXmodifiers);}
        if(c=="{"){
          eatSuffix(stream, 2);
          return tokenChain(stream,state,["}"],RXstyle,RXmodifiers);}
        if(c=="<"){
          eatSuffix(stream, 2);
          return tokenChain(stream,state,[">"],RXstyle,RXmodifiers);}
        if(/[\^'"!~\/]/.test(c)){
          eatSuffix(stream, 1);
          return tokenChain(stream,state,[stream.eat(c)],RXstyle,RXmodifiers);}}
      else if(c=="q"){
        c=look(stream, 1);
        if(c=="("){
          eatSuffix(stream, 2);
          return tokenChain(stream,state,[")"],"string");}
        if(c=="["){
          eatSuffix(stream, 2);
          return tokenChain(stream,state,["]"],"string");}
        if(c=="{"){
          eatSuffix(stream, 2);
          return tokenChain(stream,state,["}"],"string");}
        if(c=="<"){
          eatSuffix(stream, 2);
          return tokenChain(stream,state,[">"],"string");}
        if(/[\^'"!~\/]/.test(c)){
          eatSuffix(stream, 1);
          return tokenChain(stream,state,[stream.eat(c)],"string");}}
      else if(c=="w"){
        c=look(stream, 1);
        if(c=="("){
          eatSuffix(stream, 2);
          return tokenChain(stream,state,[")"],"bracket");}
        if(c=="["){
          eatSuffix(stream, 2);
          return tokenChain(stream,state,["]"],"bracket");}
        if(c=="{"){
          eatSuffix(stream, 2);
          return tokenChain(stream,state,["}"],"bracket");}
        if(c=="<"){
          eatSuffix(stream, 2);
          return tokenChain(stream,state,[">"],"bracket");}
        if(/[\^'"!~\/]/.test(c)){
          eatSuffix(stream, 1);
          return tokenChain(stream,state,[stream.eat(c)],"bracket");}}
      else if(c=="r"){
        c=look(stream, 1);
        if(c=="("){
          eatSuffix(stream, 2);
          return tokenChain(stream,state,[")"],RXstyle,RXmodifiers);}
        if(c=="["){
          eatSuffix(stream, 2);
          return tokenChain(stream,state,["]"],RXstyle,RXmodifiers);}
        if(c=="{"){
          eatSuffix(stream, 2);
          return tokenChain(stream,state,["}"],RXstyle,RXmodifiers);}
        if(c=="<"){
          eatSuffix(stream, 2);
          return tokenChain(stream,state,[">"],RXstyle,RXmodifiers);}
        if(/[\^'"!~\/]/.test(c)){
          eatSuffix(stream, 1);
          return tokenChain(stream,state,[stream.eat(c)],RXstyle,RXmodifiers);}}
      else if(/[\^'"!~\/(\[{<]/.test(c)){
        if(c=="("){
          eatSuffix(stream, 1);
          return tokenChain(stream,state,[")"],"string");}
        if(c=="["){
          eatSuffix(stream, 1);
          return tokenChain(stream,state,["]"],"string");}
        if(c=="{"){
          eatSuffix(stream, 1);
          return tokenChain(stream,state,["}"],"string");}
        if(c=="<"){
          eatSuffix(stream, 1);
          return tokenChain(stream,state,[">"],"string");}
        if(/[\^'"!~\/]/.test(c)){
          return tokenChain(stream,state,[stream.eat(c)],"string");}}}}
  if(ch=="m"){
    var c=look(stream, -2);
    if(!(c&&/\w/.test(c))){
      c=stream.eat(/[(\[{<\^'"!~\/]/);
      if(c){
        if(/[\^'"!~\/]/.test(c)){
          return tokenChain(stream,state,[c],RXstyle,RXmodifiers);}
        if(c=="("){
          return tokenChain(stream,state,[")"],RXstyle,RXmodifiers);}
        if(c=="["){
          return tokenChain(stream,state,["]"],RXstyle,RXmodifiers);}
        if(c=="{"){
          return tokenChain(stream,state,["}"],RXstyle,RXmodifiers);}
        if(c=="<"){
          return tokenChain(stream,state,[">"],RXstyle,RXmodifiers);}}}}
  if(ch=="s"){
    var c=/[\/>\]})\w]/.test(look(stream, -2));
    if(!c){
      c=stream.eat(/[(\[{<\^'"!~\/]/);
      if(c){
        if(c=="[")
          return tokenChain(stream,state,["]","]"],RXstyle,RXmodifiers);
        if(c=="{")
          return tokenChain(stream,state,["}","}"],RXstyle,RXmodifiers);
        if(c=="<")
          return tokenChain(stream,state,[">",">"],RXstyle,RXmodifiers);
        if(c=="(")
          return tokenChain(stream,state,[")",")"],RXstyle,RXmodifiers);
        return tokenChain(stream,state,[c,c],RXstyle,RXmodifiers);}}}
  if(ch=="y"){
    var c=/[\/>\]})\w]/.test(look(stream, -2));
    if(!c){
      c=stream.eat(/[(\[{<\^'"!~\/]/);
      if(c){
        if(c=="[")
          return tokenChain(stream,state,["]","]"],RXstyle,RXmodifiers);
        if(c=="{")
          return tokenChain(stream,state,["}","}"],RXstyle,RXmodifiers);
        if(c=="<")
          return tokenChain(stream,state,[">",">"],RXstyle,RXmodifiers);
        if(c=="(")
          return tokenChain(stream,state,[")",")"],RXstyle,RXmodifiers);
        return tokenChain(stream,state,[c,c],RXstyle,RXmodifiers);}}}
  if(ch=="t"){
    var c=/[\/>\]})\w]/.test(look(stream, -2));
    if(!c){
      c=stream.eat("r");if(c){
        c=stream.eat(/[(\[{<\^'"!~\/]/);
        if(c){
          if(c=="[")
            return tokenChain(stream,state,["]","]"],RXstyle,RXmodifiers);
          if(c=="{")
            return tokenChain(stream,state,["}","}"],RXstyle,RXmodifiers);
          if(c=="<")
            return tokenChain(stream,state,[">",">"],RXstyle,RXmodifiers);
          if(c=="(")
            return tokenChain(stream,state,[")",")"],RXstyle,RXmodifiers);
          return tokenChain(stream,state,[c,c],RXstyle,RXmodifiers);}}}}
  if(ch=="`"){
    return tokenChain(stream,state,[ch],"builtin");}
  if(ch=="/"){
    if(!/~\s*$/.test(prefix(stream)))
      return "operator";
    else
      return tokenChain(stream,state,[ch],RXstyle,RXmodifiers);}
  if(ch=="$"){
    var p=stream.pos;
    if(stream.eatWhile(/\d/)||stream.eat("{")&&stream.eatWhile(/\d/)&&stream.eat("}"))
      return "builtin";
    else
      stream.pos=p;}
  if(/[$@%]/.test(ch)){
    var p=stream.pos;
    if(stream.eat("^")&&stream.eat(/[A-Z]/)||!/[@$%&]/.test(look(stream, -2))&&stream.eat(/[=|\\\-#?@;:&`~\^!\[\]*'"$+.,\/<>()]/)){
      var c=stream.current();
      if(PERL[c])
        return "builtin";}
    stream.pos=p;}
  if(/[$@%&]/.test(ch)){
    if(stream.eatWhile(/[\w$]/)||stream.eat("{")&&stream.eatWhile(/[\w$]/)&&stream.eat("}")){
      var c=stream.current();
      if(PERL[c])
        return "builtin";
      else
        return "variable";}}
  if(ch=="#"){
    if(look(stream, -2)!="$"){
      stream.skipToEnd();
      return "comment";}}
  if(/[:+\-\^*$&%@=<>!?|\/~\.]/.test(ch)){
    var p=stream.pos;
    stream.eatWhile(/[:+\-\^*$&%@=<>!?|\/~\.]/);
    if(PERL[stream.current()])
      return "operator";
    else
      stream.pos=p;}
  if(ch=="_"){
    if(stream.pos==1){
      if(suffix(stream, 6)=="_END__"){
        return tokenChain(stream,state,['\0'],"comment");}
      else if(suffix(stream, 7)=="_DATA__"){
        return tokenChain(stream,state,['\0'],"builtin");}
      else if(suffix(stream, 7)=="_C__"){
        return tokenChain(stream,state,['\0'],"string");}}}
  if(/\w/.test(ch)){
    var p=stream.pos;
    if(look(stream, -2)=="{"&&(look(stream, 0)=="}"||stream.eatWhile(/\w/)&&look(stream, 0)=="}"))
      return "string";
    else
      stream.pos=p;}
  if(/[A-Z]/.test(ch)){
    var l=look(stream, -2);
    var p=stream.pos;
    stream.eatWhile(/[A-Z_]/);
    if(/[\da-z]/.test(look(stream, 0))){
      stream.pos=p;}
    else {
      var c=PERL[stream.current()];
      if(!c)
        return "meta";
      if(c[1])
        c=c[0];
      if(l!=":"){
        if(c==1)
          return "keyword";
        else if(c==2)
          return "def";
        else if(c==3)
          return "atom";
        else if(c==4)
          return "operator";
        else if(c==5)
          return "builtin";
        else
          return "meta";}
      else
        return "meta";}}
  if(/[a-zA-Z_]/.test(ch)){
    var l=look(stream, -2);
    stream.eatWhile(/\w/);
    var c=PERL[stream.current()];
    if(!c)
      return "meta";
    if(c[1])
      c=c[0];
    if(l!=":"){
      if(c==1)
        return "keyword";
      else if(c==2)
        return "def";
      else if(c==3)
        return "atom";
      else if(c==4)
        return "operator";
      else if(c==5)
        return "builtin";
      else
        return "meta";}
    else
      return "meta";}
  return null;}

const perl = {
  name: "perl",

  startState: function() {
    return {
      tokenize: tokenPerl,
      chain: null,
      style: null,
      tail: null
    };
  },
  token: function(stream, state) {
    return (state.tokenize || tokenPerl)(stream, state);
  },
  languageData: {
    commentTokens: {line: "#"},
    wordChars: "$"
  }
};

export { perl };
