
             -=*  Syntax::Highlight::Perl::Improved v1.01  *=-

Please note:  Right now, this is simply a bug-fixed version of Cory John's
original Syntax::Highlight::Perl,  since it appears that  he is no  longer
maintaining the module. This may eventually change. (See the ChangeLog for
more information.)  --David C.Y. Liu

This is a  module  for  marking  up  Perl  code  files  for  presentation,
printing,  or  publication.  This  markup  can  be  made  up  of any user-
specified strings  and  can  include  anything  ranging  from  HTML/XML to
PostScript  formatting  codes  to   ANSI  escape  sequences  to  abstract,
binary-data markups.

The current version  of  the  module  is  suited  best  to  one-shot, full
document processing that is  not  exceedingly  time-critical.  No attempts
have yet  been  made  to  optimize  the  formatting  routines.  It  is not
inordinately   slow   but  there  is  a  small-but-noticeable  delay  when
rendering  anything  but  the  most  simple  of  code  files.  You can try
out  the  included  command-line  viewing  script  (viewperl)  to  see how
it runs on your  system.  The  delay  is  not  usually  noticeable  in CGI
scripts, as it is usually overshadowed by the latency of the internet.

The other main  reason  that  the  current  version  of  the module is not
well  suited  for  time-critical,  repeated  tasks  (an  example  of  such
a task  might  be  syntax  highlighting  in  an  editor,  where the active
line  should  be  re-processed    after   every  keystroke,  and  possibly
following lines as well) is  that  it  has  no  method of "back-tracking,"
or revising a token that has already  been  formatted without reformatting
the entire string.  Using  our  example  of  a syntax highlighting editor,
this means that we would  have  to  re-process  the  entire document every
time   the  user  presses  a  key.  This  would  introduce  a  prohibitive
delay in the response  time  of  the  program.  (A  way  around this would
be to save a  "state-copy"  of  the  document  at  the  point  just before
the active line  but  this  requires  a  fast  state-copying  routine, and
the    only   current  method  for  state-copying  --  calling  the  new()
method on an existing  object  --  uses  string  eval  (a la Data::Dumper)
to  perform  the  necessary  deep-copy  of  the  data  structure. This may
be addressed in the next version.)

The  lack  of  a  back-tracking  feature  also  puts  a  limitation on the
module's ability to  handle  certain  Perl  constructs.  Two good examples
of this type of construct are the  x  and  e  modifiers to certain Regular
Expression  operators.  We  cannot  tell  before  we  encounter  them that
we should be formatting the  Regular  Expression  differently  than usual,
and yet there may  be  several  lines  of  code  that  should be formatted
specially before  we  get  to  them!  I  cannot,  as  of  yet,  think of a
good way  to  accomplish  this,  or  even  if  it's  possible.  If you can
think of a way to do it, please let me know.


                            -=*  VIEWPERL  *=-

A useful utility that  uses  the  module  has  been included. This utility
allows you to view  Perl  programs  or  modules  quickly  from the command
line,  fully  syntax  highlighted.  (Note  that  this  utility  uses  ANSI
color escape sequences, so your terminal must support them.)

To use viewperl,  just  make  it  executable  and  place  it  somewhere on
your path.  Then  just  type  `viewperl  FILE'  or  `viewperl  -m MODULE',
where FILE is the name  of  a  file  or  MODULE  is  the  name of a module
installed on  your  system  (in  the  form  you  would  `use'  it  in your
script;  eg:  Syntax::Highlight::Perl).  You  can  also  pipe  or redirect
data  into  viewperl.  Typing  `viewperl'  with  no  file  names causes it
to  read  from  the  standard  input.  You  can  also  use  the  -c option
to specify a string of code to format from the command line.

You can turn  on  line  numbering  with  the  -l  option,  or you can hide
any inline  POD  using  the  -P  option.  Type  `viewperl  --help'  for  a
list of all the options available, as well as a description of each.
