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'.

The sample programs under eg/ directory and test programs under t/ directory in the Term::ReadLine::Gnu distribution include many example of this module.

Minimal Set of Methods defined by Term::ReadLine

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.

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 of such a 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.

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.

CallbackHandlerInstall(PROMPT, LHANDLER)

This method provides the function rl_callback_handler_install() with the following addtional feature compatible with readline method; ornament feature, Term::ReadLine::Perl compatible completion function, histroy expansion, and addition to history buffer.

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.

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())

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()

save_prompt

        void    rl_save_prompt()

restore_prompt

        void    rl_restore_prompt()

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()

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 ommited, the max length of an item in @matches is used.

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()

Readline Signal Handling

cleanup_after_signal

        void    rl_cleanup_after_signal()       # GRL 4.0

free_line_state

        void    rl_free_line_state()    # GRL 4.0

reset_after_signal

        void    rl_reset_after_signal() # GRL 4.0

resize_terminal

        void    rl_resize_terminal()    # GRL 4.0

set_signals

        int     rl_set_signals()        # GRL 4.0

clear_signals

        int     rl_clear_signals()      # GRL 4.0

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)

list_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. This is a replacement of unstifle_history().

unstifle_history

        int     unstifle_history()

This is equivalent with 'stifle_history(undef)'.

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])

        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 aliase of read_history_range().

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)

Note that this function returns expansion in scalar context.

history_arg_extract(LINE, [FIRST [,LAST]])

        str history_arg_extract(str line, int first = 0, int last = '$')

get_history_event(STRING, CINDEX [,QCHAR])

        (str text, int cindex) = get_history_event(str  string,
                                                   int  cindex,
                                                   char qchar = '\0')

history_tokenize(LINE)

        (@str)  history_tokenize(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
        int rl_erase_empty_line (GRL 4.0)
        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_pre_input_hook (GRL 4.0)
        pfunc rl_event_hook
        pfunc rl_getc_function
        pfunc rl_redisplay_function
        Keymap rl_executing_keymap (read only)
        Keymap rl_binding_keymap (read only)

Signal Handling Variables

        int rl_catch_signals (GRL 4.0)
        int rl_catch_sigwinch (GRL 4.0)

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
        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
        pfunc rl_ignore_some_completion_function
        pfunc rl_directory_completion_hook
        pfunc rl_completion_display_matches_hook (GRL 4.0)

History Variables

        int history_base
        int history_length
        int max_input_history (read only)
        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
        pfunc history_inhibit_expansion_function

Function References

        rl_getc
        rl_redisplay
        rl_callback_read_char
        rl_display_match_list
        filename_completion_function
        username_completion_function
        list_completion_function
        shadow_redisplay
        Tk_getc

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->{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.

completion_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 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 rl_completion_entry_function shows how to use this function.

Term::ReadLine::Gnu Specific Features

Functions

rl_get_all_function_names

Returns a list of all function names.

shadow_redisplay

A redisplay function for password input. You can use it as follows;

        $attribs->{redisplay_function} = $attribs->{shadow_redisplay};
        $line = $term->readline("password> ");

rl_filename_list

Returns candidates of filename to complete. This function can be used with completion_function and is implemented for the compatibility with Term::ReadLine::Perl.

list_completion_function

See the description of section "Custom Completion".

Variables

do_expand

When true, the history expansion is enabled. By default false.

completion_function

See the description of section "Custom Completion".

completion_word

A reference to a list of candidates to complete for list_completion_function.

Commands

operate-and-get-next

The equivalent of the Korn shell C-o 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.

display-readline-version

Shows the version of Term::ReadLine::Gnu and the one of the GNU Readline Library.

change-ornaments

Change ornaments interactively.

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-Perl-xx.tar.gz)

AUTHOR

Hiroo Hayashi <hiroo.hayashi@computer.org>

http://www.perl.org/CPAN/authors/Hiroo_HAYASHI/

TODO

GTK+ support in addition to Tk.

BUGS

rl_add_defun() can define up to 16 functions.

Ornament feature works only on prompt strings. It requires very hard hacking of display.c:rl_redisplay() in GNU Readline library to ornament input line.

newTTY() is not tested yet.

cpanm Term::ReadLine::Gnu

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