Application
Development
Michael K. Johnson
Erik W. Troan
|
|
Linux
Application Development |
Michael K. Johnson Erik W. Troan |
Readline Library Version 2.0.
This chapter describes the basic features of the GNU command line editing interface.
The following paragraphs describe the notation used to represent keystrokes.
The text C-k is read as `Control-K' and describes the character produced when the Control key is depressed and the k key is struck.
The text M-k is read as `Meta-K' and describes the character produced when the meta key (if you have one) is depressed, and the k key is struck. If you do not have a meta key, the identical keystroke can be generated by typing ESC first, and then typing k. Either process is known as metafying the k key.
The text M-C-k is read as `Meta-Control-k' and describes the character produced by metafying C-k.
In addition, several keys have their own names. Specifically, DEL, ESC, LFD, SPC, RET, and TAB all stand for themselves when seen in this text, or in an init file (see section Readline Init File, for more info).
Often during an interactive session you type in a long line of text, only to notice that the first word on the line is misspelled. The Readline library gives you a set of commands for manipulating the text as you type it in, allowing you to just fix your typo, and not forcing you to retype the majority of the line. Using these editing commands, you move the cursor to the place that needs correction, and delete or insert the text of the corrections. Then, when you are satisfied with the line, you simply press RETURN. You do not have to be at the end of the line to press RETURN; the entire line is accepted regardless of the location of the cursor within the line.
In order to enter characters into the line, simply type them. The typed character appears where the cursor was, and then the cursor moves one space to the right. If you mistype a character, you can use your erase character to back up and delete the mistyped character.
Sometimes you may miss typing a character that you wanted to type, and not notice your error until you have typed several other characters. In that case, you can type C-b to move the cursor to the left, and then correct your mistake. Afterwards, you can move the cursor to the right with C-f.
When you add text in the middle of a line, you will notice that characters to the right of the cursor are `pushed over' to make room for the text that you have inserted. Likewise, when you delete text behind the cursor, characters to the right of the cursor are `pulled back' to fill in the blank space created by the removal of the text. A list of the basic bare essentials for editing the text of an input line follows.
The above table describes the most basic possible keystrokes that you need in order to do editing of the input line. For your convenience, many other commands have been added in addition to C-b, C-f, C-d, and DEL. Here are some commands for moving more rapidly about the line.
Notice how C-f moves forward a character, while M-f moves forward a word. It is a loose convention that control keystrokes operate on characters while meta keystrokes operate on words.
Killing text means to delete the text from the line, but to save it away for later use, usually by yanking (re-inserting) it back into the line. If the description for a command says that it `kills' text, then you can be sure that you can get the text back in a different (or the same) place later.
When you use a kill command, the text is saved in a kill-ring. Any number of consecutive kills save all of the killed text together, so that when you yank it back, you get it all. The kill ring is not line specific; the text that you killed on a previously typed line is available to be yanked back later, when you are typing another line.
Here is the list of commands for killing text.
And, here is how to yank the text back into the line. Yanking means to copy the most-recently-killed text from the kill buffer.
You can pass numeric arguments to Readline commands. Sometimes the argument acts as a repeat count, other times it is the sign of the argument that is significant. If you pass a negative argument to a command which normally acts in a forward direction, that command will act in a backward direction. For example, to kill text back to the start of the line, you might type M-- C-k.
The general way to pass numeric arguments to a command is to type meta digits before the command. If the first `digit' you type is a minus sign (-), then the sign of the argument will be negative. Once you have typed one meta digit to get the argument started, you can type the remainder of the digits, and then the command. For example, to give the C-d command an argument of 10, you could type M-1 0 C-d.
Although the Readline library comes with a set of Emacs-like
keybindings installed by default,
it is possible that you would like to use a different set
of keybindings. You can customize programs that use Readline by putting
commands in an init file in your home directory. The name of this
file is taken from the value of the environment variable INPUTRC. If
that variable is unset, the default is `~/.inputrc'.
When a program which uses the Readline library starts up, the init file is read, and the key bindings are set.
In addition, the C-x C-r command re-reads this init file, thus
incorporating any changes that you might have made to it.
There are only a few basic constructs allowed in the Readline init file. Blank lines are ignored. Lines beginning with a # are comments. Lines beginning with a $ indicate conditional constructs (see section Conditional Init Constructs). Other lines denote variable settings and key bindings.
set command within the init file. Here is how you
would specify that you wish to use vi line editing commands:
set editing-mode viRight now, there are only a few variables which can be set; so few, in fact, that we just list them here:
editing-mode
editing-mode variable controls which editing mode you are
using. By default, Readline starts up in Emacs editing mode, where
the keystrokes are most similar to Emacs. This variable can be
set to either emacs or vi.
horizontal-scroll-mode
On or Off. Setting it
to On means that the text of the lines that you edit will scroll
horizontally on a single screen line when they are longer than the width
of the screen, instead of wrapping onto a new screen line. By default,
this variable is set to Off.
mark-modified-lines
On, says to display an asterisk
(`*') at the start of history lines which have been modified.
This variable is off by default.
bell-style
none, Readline never rings the bell. If set to
visible, Readline uses a visible bell if one is available.
If set to audible (the default), Readline attempts to ring
the terminal's bell.
comment-begin
vi-comment command is executed. The default value
is "#".
meta-flag
on, Readline will enable eight-bit input (it
will not strip the eighth bit from the characters it reads),
regardless of what the terminal claims it can support. The
default value is off.
convert-meta
on, Readline will convert characters with the
eigth bit set to an ASCII key sequence by stripping the eigth
bit and prepending an ESC character, converting them to a
meta-prefixed key sequence. The default value is on.
output-meta
on, Readline will display characters with the
eighth bit set directly rather than as a meta-prefixed escape
sequence. The default is off.
completion-query-items
100.
keymap
keymap names are
emacs,
emacs-standard,
emacs-meta,
emacs-ctlx,
vi,
vi-move,
vi-command, and
vi-insert.
vi is equivalent to vi-command; emacs is
equivalent to emacs-standard. The default value is emacs.
The value of the editing-mode variable also affects the
default keymap.
show-all-if-ambiguous
on,
words which have more than one possible completion cause the
matches to be listed immediately instead of ringing the bell.
The default value is off.
expand-tilde
on, tilde expansion is performed when Readline
attempts word completion. The default is off.
Control-u: universal-argument Meta-Rubout: backward-kill-word Control-o: ">&output"In the above example, `C-u' is bound to the function
universal-argument, and `C-o' is bound to run the macro
expressed on the right hand side (that is, to insert the text
`>&output' into the line).
"\C-u": universal-argument "\C-x\C-r": re-read-init-file "\e[11~": "Function Key 1"In the above example, `C-u' is bound to the function
universal-argument (just as it was in the first example),
`C-x C-r' is bound to the function re-read-init-file, and
`ESC [ 1 1 ~' is bound to insert the text `Function Key 1'.
The following escape sequences are available when specifying key
sequences:
\C-
\M-
\e
\\
\"
\'
"\C-x\\": "\\"
Readline implements a facility similar in spirit to the conditional compilation features of the C preprocessor which allows key bindings and variable settings to be performed as the result of tests. There are three parser directives used.
$if
$if construct allows bindings to be made based on the
editing mode, the terminal being used, or the application using
Readline. The text of the test extends to the end of the line;
no characters are required to isolate it.
mode
mode= form of the $if directive is used to test
whether Readline is in emacs or vi mode.
This may be used in conjunction
with the `set keymap' command, for instance, to set bindings in
the emacs-standard and emacs-ctlx keymaps only if
Readline is starting out in emacs mode.
term
term= form may be used to include terminal-specific
key bindings, perhaps to bind the key sequences output by the
terminal's function keys. The word on the right side of the
`=' is tested against the full name of the terminal and the
portion of the terminal name before the first `-'. This
allows sun to match both sun and sun-cmd,
for instance.
application
$if bash # Quote the current or previous word "\C-xq": "\eb\"\ef\"" $endif
$endif
$if command.
$else
$if directive are executed if
the test fails.
beginning-of-line (C-a)
end-of-line (C-e)
forward-char (C-f)
backward-char (C-b)
forward-word (M-f)
backward-word (M-b)
clear-screen (C-l)
redraw-current-line ()
accept-line (Newline, Return)
previous-history (C-p)
next-history (C-n)
beginning-of-history (M-<)
end-of-history (M->)
reverse-search-history (C-r)
forward-search-history (C-s)
non-incremental-reverse-search-history (M-p)
non-incremental-forward-search-history (M-n)
history-search-forward ()
history-search-backward ()
yank-nth-arg (M-C-y)
yank-last-arg (M-., M-_)
yank-nth-arg.
delete-char (C-d)
backward-delete-char (Rubout)
quoted-insert (C-q, C-v)
tab-insert (M-TAB)
self-insert (a, b, A, 1, !, ...)
transpose-chars (C-t)
transpose-words (M-t)
upcase-word (M-u)
downcase-word (M-l)
capitalize-word (M-c)
kill-line (C-k)
backward-kill-line (C-x Rubout)
unix-line-discard (C-u)
kill-whole-line ()
kill-word (M-d)
forward-word.
backward-kill-word (M-DEL)
backward-word.
unix-word-rubout (C-w)
delete-horizontal-space ()
yank (C-y)
yank-pop (M-y)
digit-argument (M-0, M-1, ... M--)
universal-argument ()
complete (TAB)
possible-completions (M-?)
insert-completions ()
possible-completions. By default, this
is not bound to a key.
start-kbd-macro (C-x ()
end-kbd-macro (C-x ))
call-last-kbd-macro (C-x e)
re-read-init-file (C-x C-r)
abort (C-g)
bell-style).
do-uppercase-version (M-a, M-b, ...)
prefix-meta (ESC)
undo (C-_, C-x C-u)
revert-line (M-r)
undo
command enough times to get back to the beginning.
tilde-expand (M-~)
dump-functions ()
While the Readline library does not have a full set of vi
editing functions, it does contain enough to allow simple editing
of the line. The Readline vi mode behaves as specified in
the Posix 1003.2 standard.
In order to switch interactively between Emacs and Vi
editing modes, use the command M-C-j (toggle-editing-mode).
The Readline default is emacs mode.
When you enter a line in vi mode, you are already placed in
`insertion' mode, as if you had typed an `i'. Pressing ESC
switches you into `command' mode, where you can edit the text of the
line with the standard vi movement keys, move to previous
history lines with `k', and following lines with `j', and
so forth.
This document describes the GNU Readline Library, a utility for aiding in the consitency of user interface across discrete programs that need to provide a command line interface.
Copyright (C) 1988, 1994 Free Software Foundation, Inc.
Permission is granted to make and distribute verbatim copies of this manual provided the copyright notice and this permission notice pare preserved on all copies.
Permission is granted to copy and distribute modified versions of this manual under the conditions for verbatim copying, provided that the entire resulting derived work is distributed under the terms of a permission notice identical to this one.
Permission is granted to copy and distribute translations of this manual into another language, under the above conditions for modified versions, except that this permission notice may be stated in a translation approved by the Foundation.
This chapter describes the interface between the GNU Readline Library and other programs. If you are a programmer, and you wish to include the features found in GNU Readline such as completion, line editing, and interactive history manipulation in your own programs, this section is for you.
Many programs provide a command line interface, such as mail,
ftp, and sh. For such programs, the default behaviour of
Readline is sufficient. This section describes how to use Readline in
the simplest way possible, perhaps to replace calls in your code to
gets() or fgets ().
The function readline () prints a prompt and then reads and returns
a single line of text from the user. The line readline
returns is allocated with malloc (); you should free ()
the line when you are done with it. The declaration for readline
in ANSI C is
char *readline (char *prompt);
So, one might say
char *line = readline ("Enter a line: ");
in order to read a line of text from the user. The line returned has the final newline removed, so only the text remains.
If readline encounters an EOF while reading the line, and the
line is empty at that point, then (char *)NULL is returned.
Otherwise, the line is ended just as if a newline had been typed.
If you want the user to be able to get at the line later, (with
C-p for example), you must call add_history () to save the
line away in a history list of such lines.
add_history (line);
For full details on the GNU History Library, see the associated manual.
It is preferable to avoid saving empty lines on the history list, since
users rarely have a burning need to reuse a blank line. Here is
a function which usefully replaces the standard gets () library
function, and has the advantage of no static buffer to overflow:
/* A static variable for holding the line. */
static char *line_read = (char *)NULL;
/* Read a string, and return a pointer to it. Returns NULL on EOF. */
char *
rl_gets ()
{
/* If the buffer has already been allocated, return the memory
to the free pool. */
if (line_read)
{
free (line_read);
line_read = (char *)NULL;
}
/* Get a line from the user. */
line_read = readline ("");
/* If the line has any text in it, save it on the history. */
if (line_read && *line_read)
add_history (line_read);
return (line_read);
}
This function gives the user the default behaviour of TAB
completion: completion on file names. If you do not want Readline to
complete on filenames, you can change the binding of the TAB key
with rl_bind_key ().
int rl_bind_key (int key, int (*function)());
rl_bind_key () takes two arguments: key is the character that
you want to bind, and function is the address of the function to
call when key is pressed. Binding TAB to rl_insert ()
makes TAB insert itself.
rl_bind_key () returns non-zero if key is not a valid
ASCII character code (between 0 and 255).
Thus, to disable the default TAB behavior, the following suffices:
rl_bind_key ('\t', rl_insert);
This code should be executed once at the start of your program; you
might write a function called initialize_readline () which
performs this and other desired initializations, such as installing
custom completers (see section Custom Completers).
Readline provides many functions for manipulating the text of the line, but it isn't possible to anticipate the needs of all programs. This section describes the various functions and variables defined within the Readline library which allow a user program to add customized functionality to Readline.
For readabilty, we declare a new type of object, called
Function. A Function is a C function which
returns an int. The type declaration for Function is:
typedef int Function ();
The reason for declaring this new type is to make it easier to write code describing pointers to C functions. Let us say we had a variable called func which was a pointer to a function. Instead of the classic C declaration
int (*)()func;
we may write
Function *func;
Similarly, there are
typedef void VFunction (); typedef char *CPFunction (); and typedef char **CPPFunction ();
for functions returning no value, pointer to char, and
pointer to pointer to char, respectively.
In order to write new functions for Readline, you need to know the calling conventions for keyboard-invoked functions, and the names of the variables that describe the current state of the line read so far.
The calling sequence for a command foo looks like
foo (int count, int key)
where count is the numeric argument (or 1 if defaulted) and key is the key that invoked this function.
It is completely up to the function as to what should be done with the numeric argument. Some functions use it as a repeat count, some as a flag, and others to choose alternate behavior (refreshing the current line as opposed to refreshing the screen, for example). Some choose to ignore it. In general, if a function uses the numeric argument as a repeat count, it should be able to do something useful with both negative and positive arguments. At the very least, it should be aware that it can be passed a negative argument.
These variables are available to function writers.
rl_line_buffer
(the point).
rl_line_buffer. When
rl_point is at the end of the line, rl_point and
rl_end are equal.
readline (), and should not be assigned to directly.
readline prints the first prompt.
The user can dynamically change the bindings of keys while using Readline. This is done by representing the function with a descriptive name. The user is able to type the descriptive name when referring to the function. Thus, in an init file, one might find
Meta-Rubout: backward-kill-word
This binds the keystroke Meta-Rubout to the function
descriptively named backward-kill-word. You, as the
programmer, should bind the functions you write to descriptive names as
well. Readline provides a function for doing that:
rl_bind_key ().
Using this function alone is sufficient for most applications. It is the recommended way to add a few functions to the default functions that Readline has built in. If you need to do something other than adding a function to Readline, you may need to use the underlying functions described below.
Key bindings take place on a keymap. The keymap is the association between the keys that the user types and the functions that get run. You can make your own keymaps, copy existing keymaps, and tell Readline which keymap to use.
malloc (); you should free () it when you are done.
Readline has several internal keymaps. These functions allow you to change which keymap is active.
set keymap inputrc line (see section Readline Init File).
You associate keys with functions through the keymap. Readline has
several internal keymaps: emacs_standard_keymap,
emacs_meta_keymap, emacs_ctlx_keymap,
vi_movement_keymap, and vi_insertion_keymap.
emacs_standard_keymap is the default, and the examples in
this manual assume that.
These functions manage key bindings.
ISFUNC), a macro
(ISMACR), or a keymap (ISKMAP). This makes new keymaps as
necessary. The initial keymap in which to do bindings is map.
inputrc file and
perform any key bindings and variable assignments found
(see section Readline Init File).
These functions allow you to find out what keys invoke named functions and the functions invoked by a particular key sequence.
ISFUNC,
ISKMAP, or ISMACR).
rl_outstream. If readable is non-zero,
the list is formatted in such a way that it can be made part of an
inputrc file and re-read.
rl_outstream.
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 rl_insert_text () or 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 rl_begin_undo_group () and
rl_end_undo_group ().
The types of events that can be undone are:
enum undo_code { UNDO_DELETE, UNDO_INSERT, UNDO_BEGIN, UNDO_END };
Notice that UNDO_DELETE means to insert some text, and
UNDO_INSERT means to delete some text. That is, the undo code
tells undo what to undo, not how to undo it. UNDO_BEGIN and
UNDO_END are tags added by rl_begin_undo_group () and
rl_end_undo_group ().
rl_insert_text () and
rl_delete_text (), but could be the result of calls to
rl_add_undo ().
rl_begin_undo_group
(). There should be one call to rl_end_undo_group ()
for each call to rl_begin_undo_group ().
0 if there was
nothing to undo, non-zero if something was undone.
Finally, if you neither insert nor delete text, but directly modify the
existing text (e.g., change its case), call rl_modifying ()
once, just before you modify the text. You must supply the indices of
the text range that you are going to modify.
rl_line_buffer.
printf. The
resulting string is displayed in the echo area. The echo area
is also used to display numeric arguments and search strings.
rl_stuff_char (), macros, and characters read from the keyboard.
rl_read_key ().
vt100).
bell-style.
The following are implemented as macros, defined in chartypes.h.
Here is a function which changes lowercase characters to their uppercase equivalents, and uppercase characters to lowercase. If this function was bound to `M-c', then typing `M-c' would change the case of the character under point. Typing `M-1 0 M-c' would change the case of the following 10 characters, leaving the cursor on the last character changed.
/* 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);
}
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.
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:
rl_complete (). This function is
called with the same arguments as other Readline
functions intended for interactive use: count and
invoking_key. It isolates the word to be completed and calls
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.
completion_matches () uses your
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 rl_completion_entry_function.
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
(char *)NULL this signals completion_matches () that there are
no more possibilities left. Usually the generator function computes the
list of possible completions when 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 malloc(); Readline
frees the strings when it has finished with them.
completion_matches ()). The default is to do filename completion.
completion_matches
(). If the value of rl_completion_entry_function is
(Function *)NULL then the default filename generator function,
filename_entry_function (), is used.
Here is the complete list of callable completion functions present in Readline.
completion_matches () and rl_completion_entry_function).
The default is to do filename
completion. This calls rl_complete_internal () with an
argument depending on invoking_key.
rl_complete
(). This calls rl_complete_internal () with an argument of
`?'.
rl_complete ().
This calls rl_complete_internal () with an argument of `*'.
(char *) which is a list of completions for
text. If there are no completions, returns (char **)NULL.
The first entry in the returned array is the substitution for text.
The remaining entries are the possible completions. The array is
terminated with a NULL pointer.
entry_func is a function of two args, and returns a
(char *). 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 NULL pointer to the caller
when there are no more matches.
completion_matches ().
NULL means to use filename_entry_function (), the default
filename completer.
rl_line_buffer saying
what the boundaries of text are. If this function exists and
returns NULL, or if this variable is set to NULL, then
rl_complete () will call the value of
rl_completion_entry_function to generate matches, otherwise the
array of strings returned will be used.
" \t\n\"\\'`@$><=;|&{(".
rl_complete_internal (). The default list is the value of
rl_basic_word_break_characters.
rl_completer_word_break_characters are treated as any other character,
unless they also appear within this list.
rl_completer_word_break_chars. This is always non-zero
on entry, and can only be changed within a completion entry generator
function.
NULL terminated array of matches.
The first element (matches[0]) is the
maximal substring common to all matches. This function can
re-arrange the list of matches as required, but each element deleted
from the array must be freed.
Here is a small application demonstrating the use of the GNU Readline
library. It is called fileman, and the source code resides in
`examples/fileman.c'. This sample application provides
completion of command names, line editing features, and access to the
history list.
/* fileman.c -- A tiny application which demonstrates how to use the
GNU Readline library. This application interactively allows users
to manipulate files and their modes. */
#include <stdio.h>
#include <sys/types.h>
#include <sys/file.h>
#include <sys/stat.h>
#include <sys/errno.h>
#include <readline/readline.h>
#include <readline/history.h>
extern char *getwd ();
extern char *xmalloc ();
/* The names of functions that actually do the manipulation. */
int com_list (), com_view (), com_rename (), com_stat (), com_pwd ();
int com_delete (), com_help (), com_cd (), com_quit ();
/* A structure which contains information on the commands this program
can understand. */
typedef struct {
char *name; /* User printable name of the function. */
Function *func; /* Function to call to do the job. */
char *doc; /* Documentation for this function. */
} COMMAND;
COMMAND commands[] = {
{ "cd", com_cd, "Change to directory DIR" },
{ "delete", com_delete, "Delete FILE" },
{ "help", com_help, "Display this text" },
{ "?", com_help, "Synonym for `help'" },
{ "list", com_list, "List files in DIR" },
{ "ls", com_list, "Synonym for `list'" },
{ "pwd", com_pwd, "Print the current working directory" },
{ "quit", com_quit, "Quit using Fileman" },
{ "rename", com_rename, "Rename FILE to NEWNAME" },
{ "stat", com_stat, "Print out statistics on FILE" },
{ "view", com_view, "View the contents of FILE" },
{ (char *)NULL, (Function *)NULL, (char *)NULL }
};
/* Forward declarations. */
char *stripwhite ();
COMMAND *find_command ();
/* The name of this program, as taken from argv[0]. */
char *progname;
/* When non-zero, this global means the user is done using this program. */
int done;
char *
dupstr (s)
int s;
{
char *r;
r = xmalloc (strlen (s) + 1);
strcpy (r, s);
return (r);
}
main (argc, argv)
int argc;
char **argv;
{
char *line, *s;
progname = argv[0];
initialize_readline (); /* Bind our completer. */
/* Loop reading and executing lines until the user quits. */
for ( ; done == 0; )
{
line = readline ("FileMan: ");
if (!line)
break;
/* Remove leading and trailing whitespace from the line.
Then, if there is anything left, add it to the history list
and execute it. */
s = stripwhite (line);
if (*s)
{
add_history (s);
execute_line (s);
}
free (line);
}
exit (0);
}
/* Execute a command line. */
int
execute_line (line)
char *line;
{
register int i;
COMMAND *command;
char *word;
/* Isolate the command word. */
i = 0;
while (line[i] && whitespace (line[i]))
i++;
word = line + i;
while (line[i] && !whitespace (line[i]))
i++;
if (line[i])
line[i++] = '\0';
command = find_command (word);
if (!command)
{
fprintf (stderr, "%s: No such command for FileMan.\n", word);
return (-1);
}
/* Get argument to command, if any. */
while (whitespace (line[i]))
i++;
word = line + i;
/* Call the function. */
return ((*(command->func)) (word));
}
/* Look up NAME as the name of a command, and return a pointer to that
command. Return a NULL pointer if NAME isn't a command name. */
COMMAND *
find_command (name)
char *name;
{
register int i;
for (i = 0; commands[i].name; i++)
if (strcmp (name, commands[i].name) == 0)
return (&commands[i]);
return ((COMMAND *)NULL);
}
/* Strip whitespace from the start and end of STRING. Return a pointer
into STRING. */
char *
stripwhite (string)
char *string;
{
register char *s, *t;
for (s = string; whitespace (*s); s++)
;
if (*s == 0)
return (s);
t = s + strlen (s) - 1;
while (t > s && whitespace (*t))
t--;
*++t = '\0';
return s;
}
/* **************************************************************** */
/* */
/* Interface to Readline Completion */
/* */
/* **************************************************************** */
char *command_generator ();
char **fileman_completion ();
/* Tell the GNU Readline library how to complete. We want to try to complete
on command names if this is the first word in the line, or on filenames
if not. */
initialize_readline ()
{
/* Allow conditional parsing of the ~/.inputrc file. */
rl_readline_name = "FileMan";
/* Tell the completer that we want a crack first. */
rl_attempted_completion_function = (CPPFunction *)fileman_completion;
}
/* Attempt to complete on the contents of TEXT. START and END show the
region of TEXT that contains the word to complete. We can use the
entire line in case we want to do some simple parsing. Return the
array of matches, or NULL if there aren't any. */
char **
fileman_completion (text, start, end)
char *text;
int start, end;
{
char **matches;
matches = (char **)NULL;
/* If this word is at the start of the line, then it is a command
to complete. Otherwise it is the name of a file in the current
directory. */
if (start == 0)
matches = completion_matches (text, command_generator);
return (matches);
}
/* Generator function for command completion. STATE lets us know whether
to start from scratch; without any state (i.e. STATE == 0), then we
start at the top of the list. */
char *
command_generator (text, state)
char *text;
int state;
{
static int list_index, len;
char *name;
/* If this is a new word to complete, initialize now. This includes
saving the length of TEXT for efficiency, and initializing the index
variable to 0. */
if (!state)
{
list_index = 0;
len = strlen (text);
}
/* Return the next name which partially matches from the command list. */
while (name = commands[list_index].name)
{
list_index++;
if (strncmp (name, text, len) == 0)
return (dupstr(name));
}
/* If no names matched, then return NULL. */
return ((char *)NULL);
}
/* **************************************************************** */
/* */
/* FileMan Commands */
/* */
/* **************************************************************** */
/* String to pass to system (). This is for the LIST, VIEW and RENAME
commands. */
static char syscom[1024];
/* List the file(s) named in arg. */
com_list (arg)
char *arg;
{
if (!arg)
arg = "";
sprintf (syscom, "ls -FClg %s", arg);
return (system (syscom));
}
com_view (arg)
char *arg;
{
if (!valid_argument ("view", arg))
return 1;
sprintf (syscom, "more %s", arg);
return (system (syscom));
}
com_rename (arg)
char *arg;
{
too_dangerous ("rename");
return (1);
}
com_stat (arg)
char *arg;
{
struct stat finfo;
if (!valid_argument ("stat", arg))
return (1);
if (stat (arg, &finfo) == -1)
{
perror (arg);
return (1);
}
printf ("Statistics for `%s':\n", arg);
printf ("%s has %d link%s, and is %d byte%s in length.\n", arg,
finfo.st_nlink,
(finfo.st_nlink == 1) ? "" : "s",
finfo.st_size,
(finfo.st_size == 1) ? "" : "s");
printf ("Inode Last Change at: %s", ctime (&finfo.st_ctime));
printf (" Last access at: %s", ctime (&finfo.st_atime));
printf (" Last modified at: %s", ctime (&finfo.st_mtime));
return (0);
}
com_delete (arg)
char *arg;
{
too_dangerous ("delete");
return (1);
}
/* Print out help for ARG, or for all of the commands if ARG is
not present. */
com_help (arg)
char *arg;
{
register int i;
int printed = 0;
for (i = 0; commands[i].name; i++)
{
if (!*arg || (strcmp (arg, commands[i].name) == 0))
{
printf ("%s\t\t%s.\n", commands[i].name, commands[i].doc);
printed++;
}
}
if (!printed)
{
printf ("No commands match `%s'. Possibilties are:\n", arg);
for (i = 0; commands[i].name; i++)
{
/* Print in six columns. */
if (printed == 6)
{
printed = 0;
printf ("\n");
}
printf ("%s\t", commands[i].name);
printed++;
}
if (printed)
printf ("\n");
}
return (0);
}
/* Change to the directory ARG. */
com_cd (arg)
char *arg;
{
if (chdir (arg) == -1)
{
perror (arg);
return 1;
}
com_pwd ("");
return (0);
}
/* Print out the current working directory. */
com_pwd (ignore)
char *ignore;
{
char dir[1024], *s;
s = getwd (dir);
if (s == 0)
{
printf ("Error getting pwd: %s\n", dir);
return 1;
}
printf ("Current directory is %s\n", dir);
return 0;
}
/* The user wishes to quit using this program. Just set DONE non-zero. */
com_quit (arg)
char *arg;
{
done = 1;
return (0);
}
/* Function which tells you that you can't do this. */
too_dangerous (caller)
char *caller;
{
fprintf (stderr,
"%s: Too dangerous for me to distribute. Write it yourself.\n",
caller);
}
/* Return non-zero if ARG is a valid argument for CALLER, else print
an error message and return zero. */
int
valid_argument (caller, arg)
char *caller, *arg;
{
if (!arg || !*arg)
{
fprintf (stderr, "%s: Argument required.\n", caller);
return (0);
}
return (1);
}
This document was generated on 16 September 1996 using the texi2html translator version 1.51.