Term::ReadLine::Gnu(3) Perl extension for the GNU Readline/History Library


use Term::ReadLine; # Do not "use Term::ReadLine::Gnu;"
$term = new Term::ReadLine 'ProgramName';
while ( defined ($_ = $term->readline('prompt>')) ) {



This is an implementation of Term::ReadLine <http://search.cpan.org/dist/Term-ReadLine/> using the GNU Readline/History Library <http://cnswww.cns.cwru.edu/php/chet/readline/rltop.html>.

For basic functions object oriented interface is provided. These are described in the section ``Standard Methods'' and ""Term::ReadLine::Gnu" Functions".

This package also has the interface with the almost all functions and variables which are documented in the GNU Readline/History Library Manual. They are documented in the section ""Term::ReadLine::Gnu" Functions" and ""Term::ReadLine::Gnu" Variables" briefly. For further details of the GNU Readline/History Library, see GNU Readline Library Manual <http://cnswww.cns.cwru.edu/php/chet/readline/readline.html> and GNU History Library Manual <http://cnswww.cns.cwru.edu/php/chet/readline/history.html>.

There are some "Term::ReadLine::Gnu" original features. They are described in the section ""Term::ReadLine::Gnu" Specific Features"

The sample programs under eg/ directory and test programs under t/ directory in the "Term::ReadLine::Gnu" distribution <http://search.cpan.org/dist/Term-ReadLine-Gnu/> include many examples of this module.

Standard Methods

These are standard methods defined by Term::ReadLine <http://search.cpan.org/dist/Term-ReadLine/>.
returns the actual package that executes the commands. If this package is being used, "Term::ReadLine::Gnu" is returned.
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.
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".

"PROMPT" may include some escape sequences. Use "RL_PROMPT_START_IGNORE" to begin a sequence of non-printing characters, and "RL_PROMPT_END_IGNORE" to end the sequence.

"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.
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.
returns an array with two strings that give most appropriate names for files for input and output using conventions "<$in", ">$out".
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 ""Term::ReadLine::Gnu" Variables" for supported variables.

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.
makes Tk event loop run when waiting for user input (i.e., during "readline" method).
See the description of "event_loop" on Term::ReadLine <http://search.cpan.org/dist/Term-ReadLine/>.
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.
takes two arguments which are input filehandle and output filehandle. Switches to use these filehandles.
Enables UTF-8 support.

If STDIN is in UTF-8 by the "-C" command-line switch or "PERL_UNICODE" environment variable, or "IN" file handle has "utf8" IO layer, then UTF-8 support is also enabled. In other cases you need this "enableUTF8" method.

This is an original method of "Term::ReadLine:Gnu".

Term::ReadLine::Gnu Functions

All these GNU Readline/History Library functions supported are callable via method interface and have names which conform to standard conventions with the leading "rl_" stripped. For example "rl_foo()" function is called as "$term->foo()".

The titles of the following sections are same as the titles of the corresponding sections in the ``Programming with GNU Readline'' section in the GNU Readline Library Manual <http://cnswww.cns.cwru.edu/php/chet/readline/readline.html>. Refer them for further details.

Although it is preferred to use method interface, most methods have lower level functions in "Term::ReadLine::Gnu::XS" package. To use them a full qualified name is required.

Basic Behavior

The function "readline()" prints a prompt and then reads and returns a single line of text from the user.

        $_ = $term->readline('Enter a line: ');

You can change key-bindings using "bind_key(KEY, FUNCTION [,MAP])" function. The first argument, "KEY", is the character that you want bind. The second argument, "FUNCTION", is the function to call when "KEY" is pressed. The "FUNCTION" can be a reference to a Perl function (see ``Custom Functions'') or a ``named function'' named by "add_defun()" function or commands described in the ``Bindable Readline Commands'' section in the GNU Readline Library Manual <http://cnswww.cns.cwru.edu/php/chet/readline/readline.html>.

        $term->bind_key(ord "\ci, 'tab-insert');

The above example binds Control-I to the 'tab-insert' command.

Custom Functions

You can write new functions using Perl. The calling sequence for a command foo looks like

        sub foo ($count, $key) { ... }

where $count is the numeric argument (or 1 if defaulted) and $key is the key that invoked this function.

Here is an example;

        sub reverse_line {              # reverse a whole line
            my($count, $key) = @_;      # ignored in this sample function
            $t->modifying(0, $a->{end}); # save undo information
            $a->{line_buffer} = reverse $a->{line_buffer};

See the ``Writing a New Function'' section in the GNU Readline Library Manual <http://cnswww.cns.cwru.edu/php/chet/readline/readline.html> for further details.

Readline Convenience Functions

Naming a Function

"add_defun(NAME, FUNCTION [,KEY=-1])"
Add name to a Perl function "FUNCTION". If optional argument "KEY" is specified, bind it to the "FUNCTION". Returns reference to "FunctionPtr".

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

Selecting a Keymap

        Keymap  rl_make_bare_keymap()
        Keymap  rl_copy_keymap(Keymap|str map)
        Keymap  rl_make_keymap()
        Keymap  rl_discard_keymap(Keymap|str map)
        void    rl_free_keymap(Keymap|str map)
        Keymap  rl_get_keymap()
        Keymap  rl_set_keymap(Keymap|str map)
        Keymap  rl_get_keymap_by_name(str name)
        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.

"bind_key_if_unbound(KEY, FUNCTION [,MAP])"
        int     rl_bind_key_if_unbound(int key, FunctionPtr|str function,
                                       Keymap|str map = rl_get_keymap()) # GRL 5.0
"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.

"unbind_function(FUNCTION [,MAP])"
        int     rl_unbind_function(FunctionPtr|str function,
                                   Keymap|str map = rl_get_keymap())
"unbind_command(COMMAND [,MAP])"
        int     rl_unbind_command(str command,
                                  Keymap|str map = rl_get_keymap())
"bind_keyseq(KEYSEQ, FUNCTION [,MAP])"
        int     rl_bind_keyseq(str keyseq, FunctionPtr|str function,
                               Keymap|str map = rl_get_keymap()) # GRL 5.0
"set_key(KEYSEQ, FUNCTION [,MAP])"
        int     rl_set_key(str keyseq, FunctionPtr|str function,
                           Keymap|str map = rl_get_keymap())    # GRL 4.2
"bind_keyseq_if_unbound(KEYSEQ, FUNCTION [,MAP])"
        int     rl_bind_keyseq_if_unbound(str keyseq, FunctionPtr|str function,
                                          Keymap|str map = rl_get_keymap()) # GRL 5.0
"generic_bind(TYPE, KEYSEQ, DATA, [,MAP])"
        int     rl_generic_bind(int type, str keyseq,
                                FunctionPtr|Keymap|str data,
                                Keymap|str map = rl_get_keymap())
        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 further detail see GNU Readline Library Manual <http://cnswww.cns.cwru.edu/php/chet/readline/readline.html>.

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

Associating Function Names and Bindings

        FunctionPtr rl_named_function(str name)
        str     rl_get_function_name(FunctionPtr function)      # TRG original
"function_of_keyseq(KEYSEQ [,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())
        void    rl_function_dumper(int readable = 0)
        void    rl_list_funmap_names()
        (@str)  rl_funmap_names()
"add_funmap_entry(NAME, FUNCTION)"
        int     rl_add_funmap_entry(char *name, FunctionPtr|str function)

Allowing Undoing

        int     rl_begin_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)
        void    rl_free_undo_list()
        int     rl_do_undo()
"modifying([START [,END]])"
        int     rl_modifying(int start = 0, int end = rl_end)


        void    rl_redisplay()
        int     rl_forced_update_display()
        int     rl_on_new_line()
        int     rl_on_new_line_with_prompt()                    # GRL 4.1
        int     rl_reset_line_state()
        int     rl_crlf()
        int     rl_show_char(int c)
"message(FMT[, ...])"
        int     rl_message(str fmt, ...)
        int     rl_clear_message()
        void    rl_save_prompt()
        void    rl_restore_prompt()
        int     rl_expand_prompt(str prompt)
        int     rl_set_prompt(const str prompt)                 # GRL 4.2

Modifying Text

        int     rl_insert_text(str text)
"delete_text([START [,END]])"
        int     rl_delete_text(int start = 0, int end = rl_end)
"copy_text([START [,END]])"
        str     rl_copy_text(int start = 0, int end = rl_end)
"kill_text([START [,END]])"
        int     rl_kill_text(int start = 0, int end = rl_end)
        int     rl_push_macro_input(str macro)

Character Input

        int     rl_read_key()
        int     rl_getc(FILE *STREAM)
        int     rl_stuff_char(int c)
        int     rl_execute_next(int c)
        int     rl_clear_pending_input()                        # GRL 4.2
        int     rl_set_keyboard_input_timeout(int usec)         # GRL 4.2

Terminal Management

        void    rl_prep_terminal(int META_FLAG)
        void    rl_deprep_terminal()
        void    rl_tty_set_default_bindings([Keymap|str map = rl_get_keymap()]) # GRL 4.0
        void    rl_tty_unset_default_bindings([Keymap|str map = rl_get_keymap()]) # GRL 5.0
        int     rl_reset_terminal(str terminal_name = getenv($TERM))

Utility Functions

        READLINE_STATE  rl_save_state()                         # GRL 6.0
        int     rl_restore_state(READLINE_STATE)                # GRL 6.0
        Not implemented since not required for Perl.
        int     rl_free(void *mem)                              # GRL 6.0
"replace_line(TEXT [,CLEAR_UNDO])"
        int     rl_replace_line(str text, int clear_undo = 0)   # GRL 4.3
        Not implemented since not required for Perl.
        int     rl_extend_line_buffer(int len)
        int     rl_initialize()
        int     rl_ding()
        int     rl_alphabetic(int C)                            # GRL 4.2
"display_match_list(MATCHES [,LEN [,MAX]])"
        void    rl_display_match_list(\@matches, len = $#maches, max) # GRL 4.0

Since the first element of an array @matches as treated as a possible completion, it is not displayed. See the descriptions of "completion_matches()". When "MAX" is omitted, the max length of an item in @matches is used.

Miscellaneous Functions

"macro_bind(KEYSEQ, MACRO [,MAP])"
        int     rl_macro_bind(const str keyseq, const str macro, Keymap map)
        int     rl_macro_dumper(int readline)
"variable_bind(VARIABLE, VALUE)"
        int     rl_variable_bind(const str variable, const str value)
        str     rl_variable_value(const str variable)           # GRL 5.1
        int     rl_variable_dumper(int readline)
        int     rl_set_paren_blink_timeout(usec)                # GRL 4.2
        str     rl_get_termcap(cap)
    void        rl_clear_history()                              # GRL 6.3

Alternate Interface

"callback_handler_install(PROMPT, LHANDLER)"
        void    rl_callback_handler_install(str prompt, pfunc lhandler)
        void    rl_callback_read_char()
"callback_sigcleanup"                                        # GRL 7.0

        void    rl_callback_sigcleanup()
        void    rl_callback_handler_remove()

Readline Signal Handling

        void    rl_cleanup_after_signal()                       # GRL 4.0
        void    rl_free_line_state()                            # GRL 4.0
        void    rl_reset_after_signal()                         # GRL 4.0
        void    rl_echo_signal_char(int sig)                    # GRL 6.0
        void    rl_resize_terminal()                            # GRL 4.0
"set_screen_size(ROWS, COLS)"
        void    rl_set_screen_size(int ROWS, int COLS)          # GRL 4.2
        (int rows, int cols)    rl_get_screen_size()            # GRL 4.2
        void    rl_reset_screen_size()                          # GRL 5.1
        int     rl_set_signals()                                # GRL 4.0
        int     rl_clear_signals()                              # GRL 4.0

Completion Functions

        int     rl_complete_internal(int what_to_do = TAB)
        int     rl_completion_mode(FunctionPtr|str function)    # GRL 4.3
"completion_matches(TEXT [,FUNC])"
        (@str)  rl_completion_matches(str text,
                                      pfunc func = filename_completion_function)
"filename_completion_function(TEXT, STATE)"
        str     rl_filename_completion_function(str text, int state)
"username_completion_function(TEXT, STATE)"
        str     rl_username_completion_function(str text, int state)
"list_completion_function(TEXT, STATE)"
        str     list_completion_function(str text, int state)   # TRG original

History Functions

Initializing History and State Management

        void    using_history()
        HISTORY_STATE   history_get_hitory_state()              # GRL 6.3
        void    history_set_hitory_state(HISTORY_STATE)         # GRL 6.3

History List Management

        void    add_history(str string)
        void    add_history_time(str string)                    # GRL 5.0
        str     remove_history(int which)
        Not implemented since Term::ReadLine::Gnu does not support the
        member 'data' of HIST_ENTRY structure. remove_history() frees
        the memory.
        histdata_t      free_history_entry(HIST_ENTRY *histent) # GRL 5.0
"replace_history_entry(WHICH, STRING)"
        str     replace_history_entry(int which, str string)
        void    clear_history()
        int     stifle_history(int max|undef)

stifles the history list, remembering only the last "MAX" entries. If "MAX" is undef, remembers all entries. This is a replacement of "unstifle_history()".

        int     unstifle_history()

This is equivalent with "stifle_history(undef)".

        int     history_is_stifled()
"SetHistory(LINE1 [, LINE2, ...])"
sets the history of input, from where it can be used if the actual "readline" is present.

Information About the History List

        Not implemented since not required for Perl.
        HIST_ENTRY **history_list()
        int     where_history()
        str     current_history()
        str     history_get(offset)
        time_t  history_get_time(offset)                        # GRL 5.0
        int     history_total_bytes()
returns the history of input as a list, if actual "readline" is present.

Moving Around the History List

        int     history_set_pos(int pos)
        str     previous_history()
        str     next_history()

Searching the History List

"history_search(STRING [,DIRECTION])"
        int     history_search(str string, int direction = -1)
"history_search_prefix(STRING [,DIRECTION])"
        int     history_search_prefix(str string, int direction = -1)
"history_search_pos(STRING [,DIRECTION [,POS]])"
        int     history_search_pos(str string,
                                   int direction = -1,
                                   int pos = where_history())

Managing the History File

"ReadHistory([FILENAME [,FROM [,TO]]])"
        int     read_history(str filename = '~/.history',
                             int from = 0, int to = -1)
        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. "read_history()" is an alias of "read_history_range()".

        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

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

Note that this function returns "expansion" in the scalar context.

"get_history_event(STRING, CINDEX [,QCHAR])"
        (str text, int cindex) = get_history_event(str  string,
                                                   int  cindex,
                                                   char qchar = '\0')
        (@str)  history_tokenize(str string)
"history_arg_extract(STRING, [FIRST [,LAST]])"
        str history_arg_extract(str string, int first = 0, int last = '$')

Term::ReadLine::Gnu Variables

Following GNU Readline/History Library variables can be accessed by a Perl program. See GNU Readline Library Manual <http://cnswww.cns.cwru.edu/php/chet/readline/readline.html> and GNU History Library Manual <http://cnswww.cns.cwru.edu/php/chet/readline/history.html> for details of each variable. You can access them by using "Attribs" methods. Names of keys in this hash conform to standard conventions with the leading "rl_" stripped.


    $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_num_chars_to_read (GRL 4.1)
        int rl_pending_input
        int rl_dispatching
        int rl_erase_empty_line (GRL 4.0)
        str rl_prompt (read only)
        str rl_display_prompt
        int rl_already_prompted (GRL 4.1)
        str rl_library_version (read only)
        int rl_readline_version (read only)
        int rl_gnu_readline_p (GRL 4.1, read only)
        str rl_terminal_name
        str rl_readline_name
        filehandle rl_instream
        filehandle rl_outstream
        int rl_prefer_env_winsize (GRL 5.1)
        pfunc rl_last_func (GRL 4.2, read only)
        pfunc rl_startup_hook
        pfunc rl_pre_input_hook (GRL 4.0)
        pfunc rl_event_hook
        pfunc rl_getc_function
        pfunc rl_signal_event_hook (GRL 6.3)
        pfunc rl_input_available_hook (GRL 6.3)
        pfunc rl_redisplay_function
        pfunc rl_prep_term_function (GRL 2.1)
        pfunc rl_deprep_term_function (GRL 2.1)
        Keymap rl_executing_keymap (read only)
        Keymap rl_binding_keymap (read only)
        str rl_executing_macro (GRL 4.2, read only)
        int rl_executing_key (GRL 6.3, read only)
        str rl_executing_keyseq (GRL 6.3, read only)
        int rl_key_sequence_length (read only)
        int rl_readline_state (GRL 4.2)
        int rl_explicit_arg (read only)
        int rl_numeric_arg (read only)
        int rl_editing_mode (read only)

Signal Handling Variables

        int rl_catch_signals (GRL 4.0)
        int rl_catch_sigwinch (GRL 4.0)
        int rl_change_environment (GRL 6.3)

Completion Variables

        pfunc rl_completion_entry_function
        pfunc rl_attempted_completion_function
        pfunc rl_filename_quoting_function
        pfunc rl_filename_dequoting_function
        pfunc rl_char_is_quoted_p
        pfunc rl_ignore_some_completions_function
        pfunc rl_directory_completion_hook
        pfunc rl_directory_rewrite_hook (GRL 4.2)
        pfunc rl_filename_stat_hook (GRL 6.3)
        pfunc rl_filename_rewrite_hook (GRL 6.1)
        pfunc rl_completion_display_matches_hook (GRL 4.0)
        str rl_basic_word_break_characters
        str rl_basic_quote_characters
        str rl_completer_word_break_characters
        pfunc rl_completion_word_break_hook (GRL 5.0)
        str rl_completer_quote_characters
        str rl_filename_quote_characters
        str rl_special_prefixes
        int rl_completion_query_items
        int rl_completion_append_character
        int rl_completion_suppress_append (GRL 4.3)
        int rl_completion_quote_character (GRL 5.0, read only)
        int rl_completion_suppress_quote (GRL 5.0)
        int rl_completion_found_quote (GRL 5.0, read only)
        int rl_completion_mark_symlink_dirs (GRL 4.3)
        int rl_ignore_completion_duplicates
        int rl_filename_completion_desired
        int rl_filename_quoting_desired
        int rl_attempted_completion_over
        int rl_sort_completion_matches (GRL 6.0)
        int rl_completion_type (read only)
        int rl_completion_invoking_key (GRL 6.0, read only)
        int rl_inhibit_completion

History Variables

        int history_base
        int history_length
        int history_max_entries (called `max_input_history', read only)
        int history_write_timestamps (GRL 5.0)
        char history_expansion_char
        char history_subst_char
        char history_comment_char
        str history_word_delimiters (GRL 4.2)
        str history_search_delimiter_chars
        str history_no_expand_chars
        int history_quotes_inhibit_expansion
        pfunc history_inhibit_expansion_function

Function References


Custom Completion

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

Most of descriptions in this section came from GNU Readline Library Manual <http://cnswww.cns.cwru.edu/php/chet/readline/readline.html>.

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 this variable set to 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->{completion_entry_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".

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 "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,
        } 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 "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 "completion_entry_function".

A variable whose content is a reference to a function which returns a list of candidates to complete.

This variable is compatible with Term::ReadLine::Perl <http://search.cpan.org/dist/Term-ReadLine-Perl/> and very easy to use.

    use Term::ReadLine;
    my $term = new Term::ReadLine 'sample';
    my $attribs = $term->Attribs;
    $attribs->{completion_function} = sub {
        my ($text, $line, $start) = @_;
        return qw(a list of candidates to complete);
"list_completion_function(TEXT, STATE)"
A sample generator function defined by "Term::ReadLine::Gnu". Example code at "completion_entry_function" shows how to use this function.

Term::ReadLine::Gnu Specific Features

"Term::ReadLine::Gnu" Specific Functions
"CallbackHandlerInstall(PROMPT, LHANDLER)"
This method provides the function "rl_callback_handler_install()" with the following additional feature compatible with "readline" method; ornament feature, Term::ReadLine::Perl <http://search.cpan.org/dist/Term-ReadLine-Perl/> compatible completion function, history expansion, and addition to history buffer.
"call_function(FUNCTION, [COUNT [,KEY]])"
        int     rl_call_function(FunctionPtr|str function, count = 1, key = -1)
Returns a list of all function names.
A redisplay function for password input. You can use it as follows;

        $attribs->{redisplay_function} = $attribs->{shadow_redisplay};
        $line = $term->readline("password> ");
Returns candidates of filenames to complete. This function can be used with "completion_function" and is implemented for the compatibility with Term::ReadLine::Perl <http://search.cpan.org/dist/Term-ReadLine-Perl/>.
See the description of section ``Custom Completion''.

"Term::ReadLine::Gnu" Specific Variables

When true, the history expansion is enabled. By default false.
See the description of section ``Custom Completion''.
A reference to a list of candidates to complete for "list_completion_function".

"Term::ReadLine::Gnu" Specific Commands

The equivalent of the Bash "history-expand-line" editing command.
The equivalent of the Korn shell "operate-and-get-next-history-line" editing command and the Bash "operate-and-get-next".

This command is bound to "\C-o" by default for the compatibility with the Bash and Term::ReadLine::Perl <http://search.cpan.org/dist/Term-ReadLine-Perl/>.

Shows the version of "Term::ReadLine::Gnu" and the one of the GNU Readline Library.
Change ornaments interactively.


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 GNU Readline library starts up, the init file is read, and the key bindings are set.

The conditional init constructs is supported. The program name which is specified by the first argument of "new" method is used as the application construct.

For example, when your program calls "new" method as follows;

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

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

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

For further details, see the section ``Readline Init File'' in the GNU Readline Library Manual <http://cnswww.cns.cwru.edu/php/chet/readline/readline.html>


No symbols are exported by default. The following tags are defined and their symbols can be exported.

They can be exported as follows;

        use Term::ReadLine;
        BEGIN {
            import Term::ReadLine::Gnu qw(:keymap_type RL_STATE_INITIALIZED);


The environment variable "PERL_RL" governs which ReadLine clone is loaded. See the ENVIRONMENT section on Term::ReadLine <http://search.cpan.org/dist/Term-ReadLine/> for further details.


GTK+ support in addition to Tk.


Submit a bug report to rt.cpan.org <https://rt.cpan.org/Dist/Display.html?Name=Term-ReadLine-Gnu>.
"add_defun()" can define up to 16 functions.
Some functions and variables do not have test code yet. Your contribution is welcome. See t/readline.t for details.
If the pager command (| or ||) in Perl debugger causes segmentation fault, you need to fix perl5db.pl. See <https://rt.perl.org/Public/Bug/Display.html?id=121456> for details.


Copyright (c) 1996-2016 Hiroo Hayashi. All rights reserved.

This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.