Term::ReadLine - Perl interface to various C<readline> packages. If no real package is found, substitutes stubs instead of basic functions. |
Term::ReadLine - Perl interface to various readline
packages. If
no real package is found, substitutes stubs instead of basic functions.
use Term::ReadLine; my $term = new Term::ReadLine 'Simple Perl calc'; my $prompt = "Enter your arithmetic expression: "; my $OUT = $term->OUT || \*STDOUT; while ( defined ($_ = $term->readline($prompt)) ) { my $res = eval($_), "\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.
ReadLine
Term::ReadLine::Gnu
, Term::ReadLine::Perl
,
Term::ReadLine::Stub
.
new
IN
and OUT
filehandles. These
arguments should be globs.
readline
readline
support. Trailing newline is removed. Returns undef
on EOF
.
addhistory
readline
is present.
IN
, $OUT
undef
if readline
input and output cannot be used for Perl.
MinLine
undef
means do not include anything into
history. Returns the old value.
findConsole
"<$in"
, ">out"
.
rl_
stripped.
Features
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:
tkRunning
readline
method).
ornaments
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.
newTTY
One can check whether the currently loaded ReadLine package supports
these methods by checking for corresponding Features
.
None
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).
It seems that using Term::ReadLine from Emacs minibuffer doesn't work quite right and one will get an error message like
Cannot open /dev/tty for read at ...
One possible workaround for this is to explicitly open /dev/tty like this
open (FH, "/dev/tty" ) or eval 'sub Term::ReadLine::findConsole { ("&STDIN", "&STDERR") }'; die $@ if $@; close (FH);
or you can try using the 4-argument form of Term::ReadLine->new().
Term::ReadLine - Perl interface to various C<readline> packages. If no real package is found, substitutes stubs instead of basic functions. |