.\"	$OpenBSD: editline.3,v 1.4 1999/02/27 21:57:22 deraadt Exp $
.\"	$NetBSD: editline.3,v 1.4 1997/01/14 04:17:23 lukem Exp $
.\"
.\" Copyright (c) 1997 The NetBSD Foundation, Inc.
.\" All rights reserved.
.\"
.\" This file was contributed to The NetBSD Foundation by Luke Mewburn.
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\" 1. Redistributions of source code must retain the above copyright
.\"    notice, this list of conditions and the following disclaimer.
.\" 2. Redistributions in binary form must reproduce the above copyright
.\"    notice, this list of conditions and the following disclaimer in the
.\"    documentation and/or other materials provided with the distribution.
.\" 3. All advertising materials mentioning features or use of this software
.\"    must display the following acknowledgement:
.\"        This product includes software developed by the NetBSD
.\"        Foundation, Inc. and its contributors.
.\" 4. Neither the name of The NetBSD Foundation nor the names of its
.\"    contributors may be used to endorse or promote products derived
.\"    from this software without specific prior written permission.
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
.\" ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
.\" TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
.\" PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE
.\" LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
.\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
.\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
.\" INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
.\" CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
.\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
.\" POSSIBILITY OF SUCH DAMAGE.
.\"
.Dd January 11, 1997
.Os BSD 4.4
.Dt EDITLINE 3
.Sh NAME
.Nm editline ,
.Nm el_init ,
.Nm el_end ,
.Nm el_reset ,
.Nm el_gets ,
.Nm el_getc ,
.Nm el_push ,
.Nm el_parse ,
.Nm el_set ,
.Nm el_source ,
.Nm el_resize ,
.Nm el_line ,
.Nm el_insertstr ,
.Nm el_deletestr ,
.Nm history_init ,
.Nm history_end ,
.Nm history
.Nd line editor and history functions
.Sh SYNOPSIS
.Fd #include <histedit.h>
.Ft EditLine *
.Fn el_init "const char *prog" "FILE *fin" "FILE *fout"
.Ft void
.Fn el_end "EditLine *e"
.Ft void
.Fn el_reset "EditLine *e"
.Ft const char *
.Fn el_gets "EditLine *e" "int *count"
.Ft int
.Fn el_getc "EditLine *e" "char *ch"
.Ft void
.Fn el_push "EditLine *e" "const char *str"
.Ft int
.Fn el_parse "EditLine *e" "int argc" "char *argv[]"
.Ft int
.Fn el_set "EditLine *e" "int op" "..."
.Ft int
.Fn el_source "EditLine *e" "const char *file"
.Ft void
.Fn el_resize "EditLine *e"
.Ft const LineInfo *
.Fn el_line "EditLine *e"
.Ft int
.Fn el_insertstr "EditLine *e" "char *str"
.Ft void
.Fn el_deletestr "EditLine *e" "int count"
.Ft History *
.Fn history_init
.Ft void
.Fn history_end "History *h"
.Ft HistEvent *
.Fn history "History *h" "int op" "..."
.Sh DESCRIPTION
The
.Nm
library provides generic line editing and history functions,
similar to those found in
.Xr sh 1 .
.Pp
These functions are available in the
.Nm libedit
library (which needs the
.Nm libtermcap
library).
Programs should be linked with
.Fl ledit ltermcap .
.Sh LINE EDITING FUNCTIONS
The line editing functions use a common data structure,
.Fa editline ,
which is created by
.Fn el_init
and freed by
.Fn el_end .
.Pp
The following functions are available:
.Bl -tag -width 4n
.It Fn el_init
Initialise the line editor, and return a data structure
to be used by all other line editing functions.
.Fa prog
is the name of the invoking program, used when reading the
.Xr editrc 5
file to determine which settings to use.
.Fa fin
and
.Fa fout
are the input and output streams (respectively) to use.
In this documentation, references to
.Dq the tty
are actually to this input/output stream combination.
.It Fn el_end
Clean up and finish with
.Fa e ,
assumed to have been created with
.Fn el_init .
.It Fn el_reset
Reset the tty and the parser.
This should be called after an error which may have upset the tty's
state.
.It Fn el_gets
Read a line from the tty.
.Fa count
is modified to contain the number of characters read.
Returns the line read if successful, or
.Dv NULL
if no characters were read or if an error occurred.
.It Fn el_getc
Read a character from the tty.
.Fa ch
is modified to contain the character read.
Returns the number of characters read if successful, -1 otherwise.
.It Fn el_push
Pushes
.Fa str
back onto the input stream.
This is used by the macro expansion mechanism.
Refer to the description of
.Ic bind
.Fl s
in
.Xr editrc 5
for more information.
.It Fn el_parse
Parses the
.Fa argv
array (which is
.Fa argc
elements in size)
to execute builtin
.Nm
commands.
If the command is prefixed with
.Dq prog:
then
.Fn el_parse
will only execute the command if
.Dq prog
matches the
.Fa prog
argument supplied to
.Fn el_init .
The return value is
-1 if the command is unknown,
0 if there was no error or
.Dq prog
didn't match, or
1 if the command returned an error.
Refer to
.Xr editrc 5
for more information.
.Pp
.Em NOTE:
.Va argv[0]
may be modified by
.Fn el_parse .
The colon between
.Dq prog
and the command, 
.Ar command ,
will be replaced with a NUL
.Po
.Dq \e0
.Pc .
.It Fn el_set
Set
.Nm
parameters.
.Fa op
determines which parameter to set, and each operation has its
own parameter list.
.Pp
The following values for
.Fa op
are supported, along with the required argument list:
.Bl -tag -width 4n
.It Dv EL_PROMPT , Fa "char *(*f)(EditLine *)"
Define prompt printing function as
.Fa f ,
which is to return a string that contains the prompt.
.It Dv EL_TERMINAL , Fa "const char *type"
Define terminal type of the tty to be
.Fa type ,
or to
.Ev TERM
if
.Fa type
is
.Dv NULL .
.It Dv EL_EDITOR , Fa "const char *mode"
Set editing mode to
.Fa mode ,
which must be one of
.Dq emacs
or
.Dq vi .
.It Dv EL_SIGNAL , Fa "int flag"
If
.Fa flag
is non-zero,
.Nm
will install its own signal handler for the following signals when
reading command input:
.Dv SIGCONT ,
.Dv SIGHUP ,
.Dv SIGINT ,
.Dv SIGQUIT ,
.Dv SIGSTOP ,
.Dv SIGTERM ,
.Dv SIGTSTP ,
and
.Dv SIGWINCH .
Otherwise, the current signal handlers will be used.
.It Dv EL_BIND , Xo
.Fa "const char *" ,
.Fa "..." ,
.Dv NULL
.Xc
Perform the
.Ic bind
builtin command.
Refer to 
.Xr editrc 5
for more information.
.It Dv EL_ECHOTC , Xo
.Fa "const char *" ,
.Fa "..." ,
.Dv NULL
.Xc
Perform the
.Ic echotc
builtin command.
Refer to 
.Xr editrc 5
for more information.
.It Dv EL_SETTC , Xo
.Fa "const char *" ,
.Fa "..." ,
.Dv NULL
.Xc
Perform the
.Ic settc
builtin command.
Refer to 
.Xr editrc 5
for more information.
.It Dv EL_SETTY , Xo
.Fa "const char *" ,
.Fa "..." ,
.Dv NULL
.Xc
Perform the
.Ic setty
builtin command.
Refer to 
.Xr editrc 5
for more information.
.It Dv EL_TELLTC , Xo
.Fa "const char *" ,
.Fa "..." ,
.Dv NULL
.Xc
Perform the
.Ic telltc
builtin command.
Refer to 
.Xr editrc 5
for more information.
.It Dv EL_ADDFN , Xo
.Fa "const char *name" ,
.Fa "const char *help" ,
.Fa "unsigned char (*func)(EditLine *e, int ch)
.Xc
Add a user defined function,
.Fn func ,
referred to as
.Fa name
which is invoked when a key which is bound to
.Fa name
is entered.
.Fa help
is a description of
.Fa name .
At invocation time,
.Fa ch
is the key which caused the invocation.
The return value of
.Fn func
should be one of:
.Bl -tag -width "CC_REDISPLAY"
.It Dv CC_NORM
Add a normal character.
.It Dv CC_NEWLINE
End of line was entered.
.It Dv CC_EOF
EOF was entered.
.It Dv CC_ARGHACK
Expecting further command input as arguments, do nothing visually.
.It Dv CC_REFRESH
Refresh display.
.It Dv CC_CURSOR
Cursor moved, so update and perform
.Dv CC_REFRESH.
.It Dv CC_REDISPLAY
Redisplay entire input line.
This is useful if a key binding outputs extra information.
.It Dv CC_ERROR
An error occurred.
Beep, and flush tty.
.It Dv CC_FATAL
Fatal error, reset tty to known state.
.El
.It Dv EL_HIST , Xo
.Fa "History *(*func)(History *, int op, ...)" ,
.Fa "const char *ptr"
.Xc
Defines which history function to use, which is usually
.Fn history .
.Fa ptr
should be the value returned by
.Fn history_init .
.El
.It Fn el_source
Initialise
.Nm
by reading the contents of 
.Fa file .
.Fn el_parse
is called for each line in
.Fa file .
If
.Fa file
is
.Dv NULL ,
try
.Pa $PWD/.editrc
then
.Pa $HOME/.editrc .
Refer to
.Xr editrc 5
for details on the format of
.Fa file .
.It Fn el_resize
Must be called if the terminal size changes.
If
.Dv EL_SIGNAL
has been set with
.Fn el_set ,
then this is done automatically.
Otherwise, it's the responsibility of the application to call
.Fn el_resize
on the appropriate occasions.
.It Fn el_line
Return the editing information for the current line in a
.Fa lineinfo
structure, which is defined as follows:
.Bd -literal
typedef struct lineinfo {
    const char *buffer;    /* address of buffer */
    const char *cursor;    /* address of cursor */
    const char *lastchar;  /* address of last character */
} LineInfo;
.Ed
.It Fn el_insertstr
Insert
.Fa str
into the line at the cursor.
Returns -1 if
.Fa str
is empty or won't fit, and 0 otherwise.
.It Fn el_deletestr
Delete
.Fa num
characters before the cursor.
.El
.Sh HISTORY LIST FUNCTIONS
The history functions use a common data structure,
.Fa history ,
which is created by
.Fn history_init
and freed by
.Fn history_end .
.Pp
The following functions are available:
.Bl -tag -width 4n
.It Fn history_init
Initialise the history list, and return a data structure
to be used by all other history list functions.
.It Fn history_end
Clean up and finish with
.Fa h ,
assumed to have been created with
.Fn history_init .
.It Fn history
Perform operation
.Fa op
on the history list, with optional arguments as needed by the
operation.
The following values for
.Fa op
are supported, along with the required argument list:
.Bl -tag -width 4n
.It Dv H_EVENT , Fa "int size"
Set size of history to
.Fa size
elements.
.It Dv H_END
Cleans up and finishes with
.Fa h ,
assumed to be created with
.Fn history_init .
.It Dv H_CLEAR
Clear the history.
.It Dv H_FUNC , Xo
.Fa "void *ptr" ,
.Fa "history_gfun_t first" ,
.Fa "history_gfun_t next" ,
.Fa "history_gfun_t last" ,
.Fa "history_gfun_t prev" ,
.Fa "history_gfun_t curr" ,
.Fa "history_vfun_t clear" ,
.Fa "history_efun_t enter" ,
.Fa "history_efun_t add"
.Xc
Define functions to perform various history operations.
.Fa ptr
is the argument given to a function when it's invoked.
.It Dv H_FIRST
Return the first element in the history.
.It Dv H_LAST
Return the last element in the history.
.It Dv H_PREV
Return the previous element in the history.
.It Dv H_NEXT
Return the next element in the history.
.It Dv H_CURR
Return the current element in the history.
.It Dv H_ADD , Fa "const char *str"
Append
.Fa str
to the current element of the history, or create an element with
.Dv H_ENTER
if there isn't one.
.It Dv H_ENTER , Fa "const char *str"
Add
.Fa str
as a new element to the history, and, if necessary, 
removing the oldest entry to keep the list to the created size.
.It Dv H_PREV_STR , Fa "const char *str"
Return the closest previous event that starts with
.Fa str .
.It Dv H_NEXT_STR , Fa "const char *str"
Return the closest next event that starts with
.Fa str .
.It Dv H_PREV_EVENT , Fa "int e"
Return the previous event numbered
.Fa e .
.It Dv H_NEXT_EVENT , Fa "int e"
Return the next event numbered
.Fa e .
.It Dv H_LOAD , Fa "const char *file"
Load the history list stored in
.Fa file .
.It Dv H_SAVE , Fa "const char *file"
Save the history list to
.Fa file .
.El
.El
.\"XXX.Sh EXAMPLES
.\"XXX: provide some examples
.Sh SEE ALSO
.Xr editrc 5 ,
.Xr sh 1 ,
.Xr signal 3 ,
.Xr termcap 3
.Sh HISTORY
The
.Nm
library first appeared in
.Bx 4.4 .
.Sh AUTHORS
The
.Nm
library was written by Christos Zoulas,
and this manual was written by Luke Mewburn.
.Sh BUGS
This documentation is probably incomplete.
.Pp
.Fn el_parse
should not modify the supplied
.Va argv[0] .
.Pp
The tokenization functions are not publically defined in
.Fd <histedit.h>