Term::ReadLine - Perl interface to various readline
packages. If no real package is found, substitutes stubs instead of basic
functions.
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/; }
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.
All the supported functions should be called as methods, i.e., either as
$term = new Term::ReadLine 'name';
or as
$term->addhistory('row');
where $term
is a return value of Term::ReadLine->Init.
Term::ReadLine::Gnu
, Term::ReadLine::Perl
,
Term::ReadLine::Stub Exporter
.
IN
and OUT
filehandles. These arguments should be globs.
readline
support. Trailing newline is removed. Returns undef on EOF
.
readline
is present.
readline
input and output cannot be used for Perl.
"<$in"
, ">out"
.
rl_
stripped.
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.
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:
readline
method).
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 standout, last two to make
the input line standout.
One can check whether the currently loaded ReadLine package supports these
methods by checking for corresponding Features
.
None
The envrironment 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).
If rather than formatting bugs, you encounter substantive content errors in these documents, such as mistakes in the explanations or code, please use the perlbug utility included with the Perl distribution.