rltech.texinfo

linux下bash的源码

Print the readline function names and the key sequences currently
bound to them to @code{rl_outstream}.  If @var{readable} is non-zero,
the list is formatted in such a way that it can be made part of an
@code{inputrc} file and re-read.
@end deftypefun

@deftypefun void rl_list_funmap_names ()
Print the names of all bindable Readline functions to @code{rl_outstream}.
@end deftypefun

@node Allowing Undoing
@subsection Allowing Undoing

Supporting the undo command is a painless thing, and makes your
functions much more useful.  It is certainly easy to try
something if you know you can undo it.  I could use an undo function for
the stock market.

If your function simply inserts text once, or deletes text once, and
uses @code{rl_insert_text ()} or @code{rl_delete_text ()} to do it, then
undoing is already done for you automatically.

If you do multiple insertions or multiple deletions, or any combination
of these operations, you should group them together into one operation.
This is done with @code{rl_begin_undo_group ()} and
@code{rl_end_undo_group ()}.

The types of events that can be undone are:

@example
enum undo_code @{ UNDO_DELETE, UNDO_INSERT, UNDO_BEGIN, UNDO_END @}; 
@end example

Notice that @code{UNDO_DELETE} means to insert some text, and
@code{UNDO_INSERT} means to delete some text.  That is, the undo code
tells undo what to undo, not how to undo it.  @code{UNDO_BEGIN} and
@code{UNDO_END} are tags added by @code{rl_begin_undo_group ()} and
@code{rl_end_undo_group ()}.

@deftypefun int rl_begin_undo_group ()
Begins saving undo information in a group construct.  The undo
information usually comes from calls to @code{rl_insert_text ()} and
@code{rl_delete_text ()}, but could be the result of calls to
@code{rl_add_undo ()}.
@end deftypefun

@deftypefun int rl_end_undo_group ()
Closes the current undo group started with @code{rl_begin_undo_group
()}.  There should be one call to @code{rl_end_undo_group ()}
for each call to @code{rl_begin_undo_group ()}.
@end deftypefun

@deftypefun void rl_add_undo (enum undo_code what, int start, int end, char *text)
Remember how to undo an event (according to @var{what}).  The affected
text runs from @var{start} to @var{end}, and encompasses @var{text}.
@end deftypefun

@deftypefun void free_undo_list ()
Free the existing undo list.
@end deftypefun

@deftypefun int rl_do_undo ()
Undo the first thing on the undo list.  Returns @code{0} if there was
nothing to undo, non-zero if something was undone.
@end deftypefun

Finally, if you neither insert nor delete text, but directly modify the
existing text (e.g., change its case), call @code{rl_modifying ()}
once, just before you modify the text.  You must supply the indices of
the text range that you are going to modify.

@deftypefun int rl_modifying (int start, int end)
Tell Readline to save the text between @var{start} and @var{end} as a
single undo unit.  It is assumed that you will subsequently modify
that text.
@end deftypefun

@node Redisplay
@subsection Redisplay

@deftypefun int rl_redisplay ()
Change what's displayed on the screen to reflect the current contents
of @code{rl_line_buffer}.
@end deftypefun

@deftypefun int rl_forced_update_display ()
Force the line to be updated and redisplayed, whether or not
Readline thinks the screen display is correct.
@end deftypefun

@deftypefun int rl_on_new_line ()
Tell the update routines that we have moved onto a new (empty) line,
usually after ouputting a newline.
@end deftypefun

@deftypefun int rl_reset_line_state ()
Reset the display state to a clean state and redisplay the current line
starting on a new line.
@end deftypefun

@deftypefun int rl_message (va_alist)
The arguments are a string as would be supplied to @code{printf}.  The
resulting string is displayed in the @dfn{echo area}.  The echo area
is also used to display numeric arguments and search strings.
@end deftypefun

@deftypefun int rl_clear_message ()
Clear the message in the echo area.
@end deftypefun

@node Modifying Text
@subsection Modifying Text

@deftypefun int rl_insert_text (char *text)
Insert @var{text} into the line at the current cursor position.
@end deftypefun

@deftypefun int rl_delete_text (int start, int end)
Delete the text between @var{start} and @var{end} in the current line.
@end deftypefun

@deftypefun {char *} rl_copy_text (int start, int end)
Return a copy of the text between @var{start} and @var{end} in
the current line.
@end deftypefun

@deftypefun int rl_kill_text (int start, int end)
Copy the text between @var{start} and @var{end} in the current line
to the kill ring, appending or prepending to the last kill if the
last command was a kill command.  The text is deleted.
If @var{start} is less than @var{end},
the text is appended, otherwise prepended.  If the last command was
not a kill, a new kill ring slot is used.
@end deftypefun

@node Utility Functions
@subsection Utility Functions

@deftypefun int rl_read_key ()
Return the next character available.  This handles input inserted into
the input stream via @var{pending input} (@pxref{Readline Variables})
and @code{rl_stuff_char ()}, macros, and characters read from the keyboard.
@end deftypefun

@deftypefun int rl_stuff_char (int c)
Insert @var{c} into the Readline input stream.  It will be "read"
before Readline attempts to read characters from the terminal with
@code{rl_read_key ()}.
@end deftypefun

@deftypefun int rl_initialize ()
Initialize or re-initialize Readline's internal state.
@end deftypefun

@deftypefun int rl_reset_terminal (char *terminal_name)
Reinitialize Readline's idea of the terminal settings using
@var{terminal_name} as the terminal type (e.g., @code{vt100}).
@end deftypefun

@deftypefun int alphabetic (int c)
Return 1 if @var{c} is an alphabetic character.
@end deftypefun

@deftypefun int numeric (int c)
Return 1 if @var{c} is a numeric character.
@end deftypefun

@deftypefun int ding ()
Ring the terminal bell, obeying the setting of @code{bell-style}.
@end deftypefun

The following are implemented as macros, defined in @code{chartypes.h}.

@deftypefun int uppercase_p (int c)
Return 1 if @var{c} is an uppercase alphabetic character.
@end deftypefun

@deftypefun int lowercase_p (int c)
Return 1 if @var{c} is a lowercase alphabetic character.
@end deftypefun

@deftypefun int digit_p (int c)
Return 1 if @var{c} is a numeric character.
@end deftypefun

@deftypefun int to_upper (int c)
If @var{c} is a lowercase alphabetic character, return the corresponding
uppercase character.
@end deftypefun

@deftypefun int to_lower (int c)
If @var{c} is an uppercase alphabetic character, return the corresponding
lowercase character.
@end deftypefun

@deftypefun int digit_value (int c)
If @var{c} is a number, return the value it represents.
@end deftypefun

@subsection An Example

Here is a function which changes lowercase characters to their uppercase
equivalents, and uppercase characters to lowercase.  If
this function was bound to @samp{M-c}, then typing @samp{M-c} would
change the case of the character under point.  Typing @samp{M-1 0 M-c}
would change the case of the following 10 characters, leaving the cursor on
the last character changed.

@example
/* Invert the case of the COUNT following characters. */
int
invert_case_line (count, key)
     int count, key;
@{
  register int start, end, i;

  start = rl_point;

  if (rl_point >= rl_end)
    return (0);

  if (count < 0)
    @{
      direction = -1;
      count = -count;
    @}
  else
    direction = 1;
      
  /* Find the end of the range to modify. */
  end = start + (count * direction);

  /* Force it to be within range. */
  if (end > rl_end)
    end = rl_end;
  else if (end < 0)
    end = 0;

  if (start == end)
    return (0);

  if (start > end)
    @{
      int temp = start;
      start = end;
      end = temp;
    @}

  /* Tell readline that we are modifying the line, so it will save
     the undo information. */
  rl_modifying (start, end);

  for (i = start; i != end; i++)
    @{
      if (uppercase_p (rl_line_buffer[i]))
        rl_line_buffer[i] = to_lower (rl_line_buffer[i]);
      else if (lowercase_p (rl_line_buffer[i]))
        rl_line_buffer[i] = to_upper (rl_line_buffer[i]);
    @}
  /* Move point to on top of the last character changed. */
  rl_point = (direction == 1) ? end - 1 : start;
  return (0);
@}
@end example

@node Custom Completers
@section Custom Completers

Typically, a program that reads commands from the user has a way of
disambiguating commands and data.  If your program is one of these, then
it can provide completion for commands, data, or both.
The following sections describe how your program and Readline
cooperate to provide this service.

@menu
* How Completing Works::	The logic used to do completion.
* Completion Functions::	Functions provided by Readline.
* Completion Variables::	Variables which control completion.
* A Short Completion Example::	An example of writing completer subroutines.
@end menu

@node How Completing Works
@subsection How Completing Works

In order to complete some text, the full list of possible completions
must be available.  That is, it is not possible to accurately
expand a partial word without knowing all of the possible words
which make sense in that context.  The Readline library provides
the user interface to completion, and two of the most common
completion functions:  filename and username.  For completing other types
of text, you must write your own completion function.  This section
describes exactly what such functions must do, and provides an example.

There are three major functions used to perform completion:

@enumerate
@item
The user-interface function @code{rl_complete ()}.  This function is
called with the same arguments as other Readline
functions intended for interactive use:  @var{count} and
@var{invoking_key}.  It isolates the word to be completed and calls
@code{completion_matches ()} to generate a list of possible completions.
It then either lists the possible completions, inserts the possible
completions, or actually performs the
completion, depending on which behavior is desired.

@item
The internal function @code{completion_matches ()} uses your
@dfn{generator} function to generate the list of possible matches, and
then returns the array of these matches.  You should place the address
of your generator function in @code{rl_completion_entry_function}.

@item
The generator function is called repeatedly from
@code{completion_matches ()}, returning a string each time.  The
arguments to the generator function are @var{text} and @var{state}.
@var{text} is the partial word to be completed.  @var{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
@code{(char *)NULL} this signals @code{completion_matches ()} that there are
no more possibilities left.  Usually the generator function computes the
list of possible completions when @var{state} is zero, and returns them
one at a time on subsequent calls.  Each string the generator function
returns as a match must be allocated with @code{malloc()}; Readline
frees the strings when it has finished with them.

@end enumerate

@deftypefun int rl_complete (int ignore, int invoking_key)
Complete the word at or before point.  You have supplied the function
that does the initial simple matching selection algorithm (see
@code{completion_matches ()}).  The default is to do filename completion.
@end deftypefun

@deftypevar {Function *} rl_completion_entry_function
This is a pointer to the generator function for @code{completion_matches
()}.  If the value of @code{rl_completion_entry_function} is
@code{(Function *)NULL} then the default filename generator function,
@code{filename_entry_function ()}, is used.
@end deftypevar

@node Completion Functions
@subsection Completion Functions

Here is the complete list of callable completion functions present in
Readline.

@deftypefun int rl_complete_internal (int what_to_do)
Complete the word at or before point.  @var{what_to_do} says what to do
with the completion.  A value of @samp{?} means list the possible
completions.  @samp{TAB} means do standard completion.  @samp{*} means
insert all of the possible completions.  @samp{!} means to display
all of the possible completions, if there is more than one, as well as
performing partial completion.
@end deftypefun

@deftypefun int rl_complete (int ignore, int invoking_key)
Complete the word at or before point.  You have supplied the function
that does the initial simple matching selection algorithm (see
@code{completion_matches ()} and @code{rl_completion_entry_function}).
The default is to do filename
completion.  This calls @code{rl_complete_internal ()} with an
argument depending on @var{invoking_key}.
@end deftypefun

@deftypefun int rl_possible_completions (int count, int invoking_key))
List the possible completions.  See description of @code{rl_complete
()}.  This calls @code{rl_complete_internal ()} with an argument of
@samp{?}.
@end deftypefun

@deftypefun int rl_insert_completions (int count, int invoking_key))
Insert the list of possible completions into the line, deleting the
partially-completed word.  See description of @code{rl_complete ()}.
This calls @code{rl_complete_internal ()} with an argument of @samp{*}.
@end deftypefun

@deftypefun {char **} completion_matches (char *text, CPFunction *entry_func)
Returns an array of @code{(char *)} which is a list of completions for
@var{text}.  If there are no completions, returns @code{(char **)NULL}.
The first entry in the returned array is the substitution for @var{text}.
The remaining entries are the possible completions.  The array is
terminated with a @code{NULL} pointer.

@var{entry_func} is a function of two args, and returns a
@code{(char *)}.  The first argument is @var{text}.  The second is a
state argument; it is zero on the first call, and non-zero on subsequent
calls.  @var{entry_func} returns a @code{NULL}  pointer to the caller
when there are no more matches.
@end deftypefun

@deftypefun {char *} filename_completion_function (char *text, int state)
A generator function for filename completion in the general case.  Note
that completion in Bash is a little different because of all
the pathnames that must be followed when looking up completions for a
command.  The Bash source is a useful reference for writing custom
completion functions.
@end deftypefun

@deftypefun {char *} username_completion_function (char *text, int state)
A completion generator for usernames.  @var{text} contains a partial
username preceded by a random character (usually @samp{~}).  As with all
completion generators, @var{state} is zero on the first call and non-zero
for subsequent calls.
@end deftypefun

@node Completion Variables
@subsection Completion Variables

@deftypevar {Function *} rl_completion_entry_function
A pointer to the generator function for @code{completion_matches ()}.
@code{NULL} means to use @code{filename_entry_function ()}, the default
filename completer.
@end deftypevar

@deftypevar {CPPFunction *} rl_attempted_completion_function
A pointer to an alternative function to create matches.
The function is called with @var{text}, @var{start}, and @var{end}.
@var{start} and @var{end} are indices in @code{rl_line_buffer} saying
what the boundaries of @var{text} are.  If this function exists and
returns @code{NULL}, or if this variable is set to @code{NULL}, then
@code{rl_complete ()} will call the value of
@code{rl_completion_entry_function} to generate matches, otherwise the
array of strings returned will be used.
@end deftypevar

@deftypevar int rl_completion_query_items
Up to this many items will be displayed in response to a
possible-completions call.  After that, we ask the user if she is sure
she wants to see them all.  The default value is 100.
@end deftypevar

@deftypevar {char *} rl_basic_word_break_characters
The basic list of characters that signal a break between words for the
completer routine.  The default value of this variable is the characters
which break words for completion in Bash, i.e.,
@code{" \t\n\"\\'`@@$><=;|&@{("}.
@end deftypevar

@deftypevar {char *} rl_completer_word_break_characters
The list of characters that signal a break between words for
@code{rl_complete_internal ()}.  The default list is the value of
@code{rl_basic_word_break_characters}.
@end deftypevar

@deftypevar {char *} rl_completer_quote_characters
List of characters which can be used to quote a substring of the line.
Completion occurs on the entire substring, and within the substring
@code{rl_completer_word_break_characters} are treated as any other character,
unless they also appear within this list.
@end deftypevar

@deftypevar {char *} rl_special_prefixes
The list of characters that are word break characters, but should be
left in @var{text} when it is passed to the completion function.
Programs can use this to help determine what kind of completing to do.
For instance, Bash sets this variable to "$@@" so that it can complete
shell variables and hostnames.
@end deftypevar

@deftypevar int rl_ignore_completion_duplicates
If non-zero, then disallow duplicates in the matches.  Default is 1.
@end deftypevar

@deftypevar int rl_filename_completion_desired
Non-zero means that the results of the matches are to be treated as
filenames.  This is @emph{always} zero on entry, and can only be changed
within a completion entry generator function.  If it is set to a non-zero