Term::ReadLine
See the current Perl documentation for Term::ReadLine.
Here is our local, out-dated (pre-5.6) version:
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)) ) { $res = eval($_), &q
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
andOUT
filehandles. These arguments should be globs. - readline
-
gets an input line, possibly with actual
readline
support. Trailing newline is removed. Returns undef onEOF
. - addhistory
-
adds the line to the history of input, from where it can be used if the
actual
readline
is 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 tonew
is recognized, andminline
should be present ifMinLine
method is not dummy.autohistory
should be present if lines are put into history automatically (maybe subject toMinLine
), andaddhistory
ifaddhistory
method is not dummy.If
Features
method reports a featureattribs
as present, the methodAttribs
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 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 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).