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.
- 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 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.
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.
None
The 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.
If the variable is not set, the best available package is loaded.