


Term::ReadLine(3pPerl Programmers Reference GuiTerm::ReadLine(3p)


NAME
       Term::ReadLine - Perl interface to various readline
       packages. If no real package is found, substitutes stubs
       instead of basic functions.

SYNOPSIS
         use Term::ReadLine;
         $term = new Term::ReadLine 'Simple Perl calc';
         $prompt = "Enter your arithmetic expression: ";
         $OUT = $term->OUT || STDOUT;
         while ( defined ($_ = $term->readline($prompt)) ) {
           $res = eval($_), "\n";
           warn $@ if $@;
           print $OUT $res, "\n" unless $@;
           $term->addhistory($_) if /\S/;
         }


DESCRIPTION
       This package is just a front end to some other packages.
       At the moment this description is written, the only such
       package is Term-ReadLine, available on CPAN near you. The
       real target of this stub package is to set up a common
       interface to whatever Readline emerges with time.

Minimal set of supported functions
       All the supported functions should be called as methods,
       i.e., either as

         $term = new Term::ReadLine 'name';

       or as

         $term->addhistory('row');

       where $term is a return value of Term::ReadLine->Init.

       ReadLine    returns the actual package that executes the
                   commands. Among possible values are
                   Term::ReadLine::Gnu, Term::ReadLine::Perl,
                   Term::ReadLine::Stub Exporter.

       new         returns the handle for subsequent calls to
                   following functions. Argument is the name of
                   the application. Optionally can be followed by
                   two arguments for IN and OUT filehandles.
                   These arguments should be globs.

       readline    gets an input line, possibly with actual
                   readline support. Trailing newline is removed.
                   Returns undef on EOF.

       addhistory  adds the line to the history of input, from
                   where it can be used if the actual readline is



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Term::ReadLine(3pPerl Programmers Reference GuiTerm::ReadLine(3p)


                   present.

       IN, $OUT    return the filehandles for input and output or
                   undef if readline input and output cannot be
                   used for Perl.

       MinLine     If argument is specified, it is an advice on
                   minimal size of line to be included into
                   history.  undef means do not include anything
                   into history. Returns the old value.

       findConsole returns an array with two strings that give
                   most appropriate names for files for input and
                   output using conventions "<$in", ">out".

       Attribs     returns a reference to a hash which describes
                   internal configuration of the package. Names
                   of keys in this hash conform to standard
                   conventions with the leading rl_ stripped.

       Features    Returns a reference to a hash with keys being
                   features present in current implementation.
                   Several optional features are used in the
                   minimal interface: appname should be present
                   if the first argument to new is recognized,
                   and minline should be present if MinLine
                   method is not dummy.  autohistory should be
                   present if lines are put into history
                   automatically (maybe subject to MinLine), and
                   addhistory if addhistory method is not dummy.

                   If Features method reports a feature attribs
                   as present, the method Attribs is not dummy.

Additional supported functions
       Actually Term::ReadLine can use some other package, that
       will support reacher set of commands.

       All these commands are callable via method interface and
       have names which conform to standard conventions with the
       leading rl_ stripped.

       The stub package included with the perl distribution
       allows some additional methods:

       tkRunning   makes Tk event loop run when waiting for user
                   input (i.e., during readline method).

       ornaments   makes the command line stand out by using
                   termcap data.  The argument to ornaments
                   should be 0, 1, or a string of a form
                   "aa,bb,cc,dd".  Four components of this string
                   should be names of terminal capacities, first
                   two will be issued to make the prompt



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Term::ReadLine(3pPerl Programmers Reference GuiTerm::ReadLine(3p)


                   standout, last two to make the input line
                   standout.

       newTTY      takes two arguments which are input filehandle
                   and output filehandle.  Switches to use these
                   filehandles.

       One can check whether the currently loaded ReadLine
       package supports these methods by checking for
       corresponding Features.

EXPORTS
       None

ENVIRONMENT
       The environment variable PERL_RL governs which ReadLine
       clone is loaded. If the value is false, a dummy interface
       is used. If the value is true, it should be tail of the
       name of the package to use, such as Perl or Gnu.

       As a special case, if the value of this variable is space-
       separated, the tail might be used to disable the ornaments
       by setting the tail to be o=0 or ornaments=0.  The head
       should be as described above, say

       If the variable is not set, or if the head of space-
       separated list is empty, the best available package is
       loaded.

         export "PERL_RL=Perl o=0"     # Use Perl ReadLine without ornaments
         export "PERL_RL= o=0"         # Use best available ReadLine without ornaments

       (Note that processing of PERL_RL for ornaments is in the
       discretion of the particular used Term::ReadLine::*
       package).

       no real package is found, substitutes stubs instead of
       basic functions."



















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