NAME

Term::ReadLine::Gnu - Perl extension for the GNU Readline/History Library

SYNOPSIS

use Term::ReadLine;
$term = new Term::ReadLine 'ProgramName';
while ( defined ($_ = $term->readline('prompt>')) ) {
  ...
}

DESCRIPTION

Overview

This is an implementation of Term::ReadLine using the GNU Readline/History Library.

For basic functions object oriented interface is provided. These are described in the section Methods.

This package also has the interface with the almost all variables and functions which are documented in the GNU Readline/History Library Manual. These variables and functions are documented in the section Variables and Functions briefly. For more detail of the GNU Readline/History Library, see 'GNU Readline Library Manual' and 'GNU History Library Manual'.

Minimal Set of Methods defined by Readline.pm

ReadLine

returns the actual package that executes the commands. If you have installed this package, possible value is Term::ReadLine::Gnu.

new(NAME,[IN[,OUT]])

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 file handles. These arguments should be globs.

readline(PROMPT[,PREPUT])

gets an input line, with actual GNU Readline support. Trailing newline is removed. Returns undef on EOF. PREPUT is an optional argument meaning the initial value of input.

The optional argument PREPUT is granted only if the value preput is in Features.

AddHistory(LINE1, LINE2, ...)

adds the lines to the history of input, from where it can be used if the actual readline is present.

IN, OUT

return the file handles for input and output or undef if readline input and output cannot be used for Perl.

MinLine([MAX])

If argument MAX 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 (variables) of the package. Names of keys in this hash conform to standard conventions with the leading rl_ stripped.

See section "Variables" for supported variables.

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. preput means the second argument to readline method is processed. getHistory and setHistory denote that the corresponding methods are present. tkRunning denotes that a Tk application may run while ReadLine is getting input (undocumented feature).

Additional Supported Methods

All these GNU Readline/History Library functions are callable via method interface and have names which conform to standard conventions with the leading rl_ stripped.

Almost methods have lower level functions in Term::ReadLine::Gnu::XS package. To use them full qualified name is required. Using method interface is preferred.

Readline Convenience Functions

Naming Function

add_defun(NAME, FUNC [,KEY=-1])

Add name to the Perl function FUNC. If optional argument KEY is specified, bind it to the FUNC. Returns reference to FunctionPtr.

  Example:
	# name name `reverse-line' to a function reverse_line(),
	# and bind it to "\C-t"
	$term->add_defun('reverse-line', \&reverse_line, "\ct");

Selecting a Keymap

make_bare_keymap

Keymap	rl_make_bare_keymap()

copy_keymap(MAP)

Keymap	rl_copy_keymap(Keymap|str map)

make_keymap

Keymap	rl_make_keymap()

discard_keymap(MAP)

Keymap	rl_discard_keymap(Keymap|str map)

get_keymap

Keymap	rl_get_keymap()

set_keymap(MAP)

Keymap	rl_set_keymap(Keymap|str map)

get_keymap_by_name(NAME)

Keymap	rl_get_keymap_by_name(str name)

get_keymap_name(MAP)

str	rl_get_keymap_name(Keymap map)

Binding Keys

bind_key(KEY, FUNCTION [,MAP])

int	rl_bind_key(int key, FunctionPtr|str function,
		    Keymap|str map = rl_get_keymap())

Bind KEY to the FUNCTION. FUNCTION is the name added by the add_defun method. If optional argument MAP is specified, binds in MAP. Returns non-zero in case of error.

unbind_key(KEY [,MAP])

int	rl_unbind_key(int key, Keymap|str map = rl_get_keymap())

Bind KEY to the null function. Returns non-zero in case of error.

generic_bind(TYPE, KEYSEQ, DATA, [,MAP])

int	rl_generic_bind(int type, str keyseq,
			FunctionPtr|Keymap|str data,
			Keymap|str map = rl_get_keymap())

parse_and_bind(LINE)

void	rl_parse_and_bind(str line)

Parse LINE as if it had been read from the ~/.inputrc file and perform any key bindings and variable assignments found. For more detail see 'GNU Readline Library Manual'.

read_init_file([FILENAME])

int	rl_read_init_file(str filename = '~/.inputrc')

Associating Function Names and Bindings

call_function(FUNCTION, [COUNT [,KEY]])

int	rl_call_function(FunctionPtr|str function, count = 1, key = -1)

named_function(NAME)

FunctionPtr rl_named_function(str name)

get_function_name(FUNCTION)

str	rl_get_function_name(FunctionPtr function)

function_of_keyseq(KEYMAP [,MAP])

(FunctionPtr|Keymap|str data, int type)
	rl_function_of_keyseq(str keyseq,
			      Keymap|str map = rl_get_keymap())

invoking_keyseqs(FUNCTION [,MAP])

(@str)	rl_invoking_keyseqs(FunctionPtr|str function,
			    Keymap|str map = rl_get_keymap())

function_dumper([READABLE])

void	rl_function_dumper(int readable = 0)

list_funmap_names

void	rl_list_funmap_names()

Allowing Undoing

begin_undo_group

int	rl_begin_undo_group()

end_undo_group

int	rl_end_undo_group()

add_undo(WHAT, START, END, TEXT)

int	rl_add_undo(int what, int start, int end, str text)

free_undo_list

void	free_undo_list()

do_undo

int	rl_do_undo()

modifying([START [,END]])

int	rl_modifying(int start = 0, int end = rl_end)

Redisplay

redisplay

void	rl_redisplay()

forced_update_display

int	rl_forced_update_display()

on_new_line

int	rl_on_new_line()

reset_line_state

int	rl_reset_line_state()

message(FMT[, ...])

int	rl_message(str fmt, ...)

clear_message

int	rl_clear_message()

Modifying Text

insert_text(TEXT)

int	rl_insert_text(str text)

delete_text([START [,END]])

int	rl_delete_text(start = 0, end = rl_end)

copy_text([START [,END]])

str	rl_copy_text(start = 0, end = rl_end)

kill_text([START [,END]])

int	rl_kill_text(start = 0, end = rl_end)

Utility Functions

read_key

int	rl_read_key()

getc(FILE)

int	rl_getc(FILE *)

stuff_char(C)

int	rl_stuff_char(int c)

initialize

int	rl_initialize()

reset_terminal([TERMINAL_NAME])

int	rl_reset_terminal(str terminal_name = getenv($TERM))

ding

int	ding()

Alternate Interface

callback_handler_install(PROMPT, LHANDLER)

void	rl_callback_handler_install(str prompt, pfunc lhandler)

callback_read_char

void	rl_callback_read_char()

callback_handler_remove

void	rl_callback_handler_remove()

Completion Functions

complete_internal([WHAT_TO_DO])

int	rl_complete_internal(int what_to_do = TAB)

completion_matches(TEXT [,FUNC])

(@str)	completion_matches(str text,
			   pfunc func = filename_completion_function)

filename_completion_function(TEXT, STATE)

str	filename_completion_function(str text, int state)

username_completion_function(TEXT, STATE)

str	username_completion_function(str text, int state)

listname_completion_function(TEXT, STATE)

str	list_completion_function(str text, int state)

History Functions

Initializing History and State Management

using_history

void	using_history()

History List Management

addhistory(STRING[, STRING, ...])

void	add_history(str string)

StifleHistory(MAX)

int	stifle_history(int max|undef)

stifles the history list, remembering only the last MAX entries. If MAX is undef, remembers all entries.

SetHistory(LINE1 [, LINE2, ...])

sets the history of input, from where it can be used if the actual readline is present.

remove_history(WHICH)

str	remove_history(int which)

replace_history_entry(WHICH, LINE)

str	replace_history_entry(int which, str line)

clear_history

void	clear_history()

history_is_stifled

int	history_is_stifled()

Information About the History List

where_history

int	where_history()

current_history

str	current_history()

history_get(OFFSET)

str	history_get(offset)

history_total_bytes

int	history_total_bytes()

GetHistory

returns the history of input as a list, if actual readline is present.

Moving Around the History List

history_set_pos(POS)

int	history_set_pos(int pos)

previous_history

str	previous_history()

next_history

str	next_history()

Searching the History List

history_search(STRING [,DIRECTION [,POS]])

int	history_search(str string,
		       int direction = -1, int pos = where_history())

history_search_prefix(STRING [,DIRECTION])

int	history_search_prefix(str string, int direction = -1)

Managing the History File

ReadHistory([FILENAME [,FROM [,TO]]])

int	read_history_range(str filename = '~/.history',
			   int from = 0, int to = -1)

adds the contents of FILENAME to the history list, a line at a time. If FILENAME is false, then read from ~/.history. Start reading at line FROM and end at TO. If FROM is omitted or zero, start at the beginning. If TO is omitted or less than FROM, then read until the end of the file. Returns true if successful, or false if not.

WriteHistory([FILENAME])

int	write_history(str filename = '~/.history')

writes the current history to FILENAME, overwriting FILENAME if necessary. If FILENAME is false, then write the history list to ~/.history. Returns true if successful, or false if not.

append_history(NELEMENTS [,FILENAME])

int	append_history(int nelements, str filename = '~/.history')

history_truncate_file([FILENAME [,NLINES]])

int	history_truncate_file(str filename = '~/.history',
			      int nlines = 0)

History Expansion

history_expand(LINE)

(int result, str expansion) history_expand(str line)

Variables

Following GNU Readline/History Library variables can be accessed from Perl program. See 'GNU Readline Library Manual' and ' GNU History Library Manual' for each variable. You can access them with Attribs methods. Names of keys in this hash conform to standard conventions with the leading rl_ stripped.

Examples:

$attribs = $term->Attribs;
$v = $attribs->{library_version};	# rl_library_version
$v = $attribs->{history_base};	# history_base

Readline Variables

str rl_line_buffer
int rl_point
int rl_end
int rl_mark
int rl_done		
int rl_pending_input
str rl_prompt (read only)
str rl_library_version (read only)
str rl_terminal_name
str rl_readline_name
filehandle rl_instream
filehandle rl_outstream
pfunc rl_startup_hook
pfunc rl_event_hook
pfunc rl_getc_function
pfunc rl_redisplay_function
Keymap rl_executing_keymap (read only)
Keymap rl_binding_keymap (read only)

Completion Variables

pfunc rl_completion_entry_function
pfunc rl_attempted_completion_function
rl_filename_quoting_function (not implemented)
rl_filename_dequoting_function (not implemented)
rl_char_is_quoted_p (not implemented)
int rl_completion_query_items
str rl_basic_word_break_characters
str rl_basic_quote_characters
str rl_completer_word_break_characters
str rl_completer_quote_characters
str rl_filename_quote_characters
str rl_special_prefixes
int rl_completion_append_character
int rl_ignore_completion_duplicates
int rl_filename_completion_desired
int rl_filename_quoting_desired
int rl_inhibit_completion
rl_ignore_some_completion_function (not implemented)
rl_directory_completion_hook (not implemented)

History Variables

int history_base
int history_length
int max_input_history (not implemented)
char history_expansion_char
char history_subst_char
char history_comment_char
str history_no_expand_chars
str history_search_delimiter_chars
int history_quotes_inhibit_expansion

Function References

rl_getc
rl_callback_read_char
filename_completion_function
username_completion_function
list_completion_function

Term::ReadLine::Gnu Specific Variables

do_expand		# if true history expansion is enabled
completion_word		# for list_completion_function

Custom Completion

In this section variables and functions for custom completion is described with examples.

Most of descriptions in this section is cited from GNU Readline Library manual.

rl_completion_entry_function

This variable holds reference refers to a generator function for completion_matches().

A generator function is called repeatedly from completion_matches(), returning a string each time. The arguments to the generator function are TEXT and STATE. TEXT is the partial word to be completed. STATE is zero the first time the function is called, allowing the generator to perform any necessary initialization, and a positive non-zero integer for each subsequent call. When the generator function returns undef this signals completion_matches() that there are no more possibilities left.

If the value is undef, built-in filename_completion_function is used.

A sample generator function, list_completion_function, is defined in Gnu.pm. You can use it as follows;

    use Term::ReadLine;
    ...
    my $term = new Term::ReadLine 'sample';
    my $attribs = $term->Attribs;
    ...
    $attribs->{rl_completion_entry_function} =
	$attribs->{'list_completion_function'};
    ...
    $attribs->{completion_word} =
	[qw(reference to a list of words which you want to use for completion)];
    $term->readline("custom completion>");

See also completion_matches.

rl_attempted_completion_function

A reference to an alternative function to create matches.

The function is called with TEXT, LINE_BUFFER, START, and END. LINE_BUFFER is a current input buffer string. START and END are indices in LINE_BUFFER saying what the boundaries of TEXT are.

If this function exists and returns null list or undef, or if this variable is set to undef, then an internal function rl_complete() will call the value of $rl_completion_entry_function to generate matches, otherwise the array of strings returned will be used.

The default value of this variable is undef. You can use it as follows;

    use Term::ReadLine;
    ...
    my $term = new Term::ReadLine 'sample';
    my $attribs = $term->Attribs;
    ...
    sub sample_completion {
        my ($text, $line, $start, $end) = @_;
        # If first word then username completion, else filename completion
        if (substr($line, 0, $start) =~ /^\s*$/) {
    	    return $term->completion_matches($text,
					     $attribs->{'username_completion_function'});
        } else {
    	    return ();
        }
    }
    ...
    $attribs->{attempted_completion_function} = \&sample_completion;

completion_matches(TEXT, ENTRY_FUNC)

Returns an array of strings which is a list of completions for TEXT. If there are no completions, returns undef. The first entry in the returned array is the substitution for TEXT. The remaining entries are the possible completions.

ENTRY_FUNC is a generator function which has two arguments, and returns a string. The first argument is TEXT. The second is a state argument; it is zero on the first call, and non-zero on subsequent calls. ENTRY_FUNC returns a undef to the caller when there are no more matches.

If the value of ENTRY_FUNC is undef, built-in filename_completion_function is used.

completion_matches is a Perl wrapper function of an internal function completion_matches(). See also $rl_completion_entry_function.

list_completion_function(TEXT, STATE)

A sample generator function defined by Term::ReadLine::Gnu.pm. Example code at rl_completion_entry_function shows how to use this function.

FILES

~/.inputrc

Readline init file. Using this file it is possible that you would like to use a different set of key bindings. When a program which uses the Readline library starts up, the init file is read, and the key bindings are set.

Conditional key binding is also available. The program name which is specified by the first argument of new method is used as the application construct.

For example, when your program call new method like this;

...
$term = new Term::ReadLine 'PerlSh';
...

your ~/.inputrc can define key bindings only for it as follows;

	...
	$if PerlSh
	Meta-Rubout: backward-kill-word
	"\C-x\C-r": re-read-init-file
        "\e[11~": "Function Key 1"
	$endif
	...

EXPORTS

None.

SEE ALSO

GNU Readline Library Manual

GNU History Library Manual

Term::ReadLine

Term::ReadLine::Perl (Term-ReadLine-xx.tar.gz)

AUTHOR

Hiroo Hayashi <hiroo.hayashi@toshiba.co.jp>

TODO

Test routines for following variable and functions are required.

rl_read_key()
rl_stuff_char()

rl_callback_handler_install()
rl_callback_read_char()
rl_callback_handler_remove()

rl_complete_internal()

history_search()
history_search_prefix()

BUGS

rl_add_defun() can define up to 16 functions.

rl_message() does not work. See display_readline_version() in t/readline.t.

cpanm Term::ReadLine::Gnu

perl -MCPAN -e shell
install Term::ReadLine::Gnu