el_get(3) line editor, history and tokenization functions

Other Alias

editline, el_init, el_end, el_reset, el_gets, el_getc, el_push, el_parse, el_set, el_source, el_resize, el_line, el_insertstr, el_deletestr, history_init, history_end, history, tok_init, tok_end, tok_reset, tok_line, tok_str

LIBRARY

Lb libedit

SYNOPSIS

In histedit.h Ft EditLine * Fn el_init const char *prog FILE *fin FILE *fout FILE *ferr 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 const char *argv[] Ft int Fn el_set EditLine *e int op ... Ft int Fn el_get 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 const char *str Ft void Fn el_deletestr EditLine *e int count Ft History * Fn history_init Ft void Fn history_end History *h Ft int Fn history History *h HistEvent *ev int op ... Ft Tokenizer * Fn tok_init const char *IFS Ft void Fn tok_end Tokenizer *t Ft void Fn tok_reset Tokenizer *t Ft int Fn tok_line Tokenizer *t const LineInfo *li int *argc const char **argv[] int *cursorc int *cursoro Ft int Fn tok_str Tokenizer *t const char *str int *argc const char **argv[]

DESCRIPTION

The library provides generic line editing, history and tokenization functions, similar to those found in sh(1).

These functions are available in the libedit library (which needs the libtermcap library). Programs should be linked with -ledit ltermcap

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 .

The following functions are available:

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 editrc(5) file to determine which settings to use. Fa fin , Fa fout and Fa ferr are the input, output, and error streams (respectively) to use. In this documentation, references to ``the tty'' are actually to this input/output stream combination.
Fn el_end
Clean up and finish with Fa e , assumed to have been created with Fn el_init .
Fn el_reset
Reset the tty and the parser. This should be called after an error which may have upset the tty's state.
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 NULL if no characters were read or if an error occurred.
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.
Fn el_push
Pushes Fa str back onto the input stream. This is used by the macro expansion mechanism. Refer to the description of bind -s in editrc(5) for more information.
Fn el_parse
Parses the Fa argv array (which is Fa argc elements in size) to execute builtin commands. If the command is prefixed with ``prog'' then Fn el_parse will only execute the command if ``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 ``prog'' didn't match, or 1 if the command returned an error. Refer to editrc(5) for more information.
Fn el_set
Set parameters. Fa op determines which parameter to set, and each operation has its own parameter list.

The following values for Fa op are supported, along with the required argument list:

EL_PROMPT , Fa char *(*f)(EditLine *)
Define prompt printing function as Fa f , which is to return a string that contains the prompt.
EL_REFRESH
Re-display the current line on the next terminal line.
EL_RPROMPT , Fa char *(*f)(EditLine *)
Define right side prompt printing function as Fa f , which is to return a string that contains the prompt.
EL_TERMINAL , Fa const char *type
Define terminal type of the tty to be Fa type , or to TERM if Fa type is NULL
EL_EDITOR , Fa const char *mode
Set editing mode to Fa mode , which must be one of ``emacs'' or ``vi''
EL_SIGNAL , Fa int flag
If Fa flag is non-zero, will install its own signal handler for the following signals when reading command input: SIGCONT SIGHUP SIGINT SIGQUIT SIGSTOP SIGTERM SIGTSTP and SIGWINCH Otherwise, the current signal handlers will be used.
EL_BIND , Fa const char * , Fa ... , NULL
Perform the bind builtin command. Refer to editrc(5) for more information.
EL_ECHOTC , Fa const char * , Fa ... , NULL
Perform the echotc builtin command. Refer to editrc(5) for more information.
EL_SETTC , Fa const char * , Fa ... , NULL
Perform the settc builtin command. Refer to editrc(5) for more information.
EL_SETTY , Fa const char * , Fa ... , NULL
Perform the setty builtin command. Refer to editrc(5) for more information.
EL_TELLTC , Fa const char * , Fa ... , NULL
Perform the telltc builtin command. Refer to editrc(5) for more information.
EL_ADDFN , Fa const char *name , Fa const char *help , Fa unsigned char (*func)(EditLine *e, int ch)
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:

CC_NORM
Add a normal character.
CC_NEWLINE
End of line was entered.
CC_EOF
EOF was entered.
CC_ARGHACK
Expecting further command input as arguments, do nothing visually.
CC_REFRESH
Refresh display.
CC_REFRESH_BEEP
Refresh display, and beep.
CC_CURSOR
Cursor moved, so update and perform CC_REFRESH
CC_REDISPLAY
Redisplay entire input line. This is useful if a key binding outputs extra information.
CC_ERROR
An error occurred. Beep, and flush tty.
CC_FATAL
Fatal error, reset tty to known state.

EL_HIST , Fa History *(*func)(History *, int op, ...) , Fa const char *ptr
Defines which history function to use, which is usually Fn history . Fa ptr should be the value returned by Fn history_init .
EL_EDITMODE , Fa int flag
If Fa flag is non-zero, editing is enabled (the default). Note that this is only an indication, and does not affect the operation of . At this time, it is the caller's responsibility to check this (using Fn el_get ) to determine if editing should be enabled or not.
EL_GETCFN , Fa int (*f)(EditLine *, char *c)
Define the character reading function as Fa f , which is to return the number of characters read and store them in Fa c . This function is called internally by Fn el_gets and Fn el_getc . The builtin function can be set or restored with the special function name ``EL_BUILTIN_GETCFN''.
EL_CLIENTDATA , Fa void *data
Register Fa data to be associated with this EditLine structure. It can be retrieved with the corresponding Fn el_get call.
EL_SETFP , Fa int fd , Fa FILE *fp
Set the current editline file pointer for ``input'' Fa fd = 0 ``output'' Fa fd = 1 or ``error'' Fa fd = 2 from Fa fp .

Fn el_get
Get parameters. Fa op determines which parameter to retrieve into Fa result . Returns 0 if successful, -1 otherwise.

The following values for Fa op are supported, along with actual type of Fa result :

EL_PROMPT , Fa char *(*f)(EditLine *)
Return a pointer to the function that displays the prompt.
EL_RPROMPT , Fa char *(*f)(EditLine *)
Return a pointer to the function that displays the rightside prompt.
EL_EDITOR , Fa const char *
Return the name of the editor, which will be one of ``emacs'' or ``vi''
EL_GETTC , Fa const char *name , Fa void *value
Return non-zero if Fa name is a valid termcap(5) capability and set Fa value to the current value of that capability.
EL_SIGNAL , Fa int *
Return non-zero if has installed private signal handlers (see Fn el_get above).
EL_EDITMODE , Fa int *
Return non-zero if editing is enabled.
EL_GETCFN , Fa int (**f)(EditLine *, char *)
Return a pointer to the function that read characters, which is equal to ``EL_BUILTIN_GETCFN'' in the case of the default builtin function.
EL_CLIENTDATA , Fa void **data
Retrieve Fa data previously registered with the corresponding Fn el_set call.
EL_UNBUFFERED , Fa int
Sets or clears unbuffered mode. In this mode, Fn el_gets will return immediately after processing a single character.
EL_PREP_TERM , Fa int
Sets or clears terminal editing mode.
EL_GETFP , Fa int fd, Fa FILE **fp
Return in Fa fp the current editline file pointer for ``input'' Fa fd = 0 ``output'' Fa fd = 1 or ``error'' Fa fd = 2

Fn el_source
Initialise by reading the contents of Fa file . Fn el_parse is called for each line in Fa file . If Fa file is NULL try $PWD/.editrc then $HOME/.editrc Refer to editrc(5) for details on the format of Fa file .
Fn el_resize
Must be called if the terminal size changes. If 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.
Fn el_line
Return the editing information for the current line in a Fa LineInfo structure, which is defined as follows: 
typedef struct lineinfo {
    const char *buffer;    /* address of buffer */
    const char *cursor;    /* address of cursor */
    const char *lastchar;  /* address of last character */
} LineInfo;

Fa buffer is not NUL terminated. This function may be called after Fn el_gets to obtain the Fa LineInfo structure pertaining to line returned by that function, and from within user defined functions added with EL_ADDFN

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.
Fn el_deletestr
Delete Fa count characters before the cursor.

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 .

The following functions are available:

Fn history_init
Initialise the history list, and return a data structure to be used by all other history list functions.
Fn history_end
Clean up and finish with Fa h , assumed to have been created with Fn history_init .
Fn history
Perform operation Fa op on the history list, with optional arguments as needed by the operation. Fa ev is changed accordingly to operation. The following values for Fa op are supported, along with the required argument list:

H_SETSIZE , Fa int size
Set size of history to Fa size elements.
H_GETSIZE
Get number of events currently in history.
H_END
Cleans up and finishes with Fa h , assumed to be created with Fn history_init .
H_CLEAR
Clear the history.
H_FUNC , 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_sfun_t set , Fa history_vfun_t clear , Fa history_efun_t enter , Fa history_efun_t add
Define functions to perform various history operations. Fa ptr is the argument given to a function when it's invoked.
H_FIRST
Return the first element in the history.
H_LAST
Return the last element in the history.
H_PREV
Return the previous element in the history.
H_NEXT
Return the next element in the history.
H_CURR
Return the current element in the history.
H_SET
Set the cursor to point to the requested element.
H_ADD , Fa const char *str
Append Fa str to the current element of the history, or perform the H_ENTER operation with argument Fa str if there is no current element.
H_APPEND , Fa const char *str
Append Fa str to the last new element of the history.
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. If H_SETUNIQUE was has been called with a non-zero arguments, the element will not be entered into the history if its contents match the ones of the current history element. If the element is entered Fn history returns 1, if it is ignored as a duplicate returns 0. Finally Fn history returns -1 if an error occurred.
H_PREV_STR , Fa const char *str
Return the closest previous event that starts with Fa str .
H_NEXT_STR , Fa const char *str
Return the closest next event that starts with Fa str .
H_PREV_EVENT , Fa int e
Return the previous event numbered Fa e .
H_NEXT_EVENT , Fa int e
Return the next event numbered Fa e .
H_LOAD , Fa const char *file
Load the history list stored in Fa file .
H_SAVE , Fa const char *file
Save the history list to Fa file .
H_SETUNIQUE , Fa int unique
Set flag that adjacent identical event strings should not be entered into the history.
H_GETUNIQUE
Retrieve the current setting if adjacent identical elements should be entered into the history.
H_DEL , Fa int e
Delete the event numbered Fa e . This function is only provided for readline(3) compatibility. The caller is responsible for free'ing the string in the returned Fa HistEvent .

Fn history returns >= 0 if the operation Fa op succeeds. Otherwise, -1 is returned and Fa ev is updated to contain more details about the error.

TOKENIZATION FUNCTIONS

The tokenization functions use a common data structure, Fa Tokenizer , which is created by Fn tok_init and freed by Fn tok_end .

The following functions are available:

Fn tok_init
Initialise the tokenizer, and return a data structure to be used by all other tokenizer functions. Fa IFS contains the Input Field Separators, which defaults to Aq space , Aq tab , and Aq newline if NULL
Fn tok_end
Clean up and finish with Fa t , assumed to have been created with Fn tok_init .
Fn tok_reset
Reset the tokenizer state. Use after a line has been successfully tokenized by Fn tok_line or Fn tok_str and before a new line is to be tokenized.
Fn tok_line
Tokenize Fa li , If successful, modify: Fa argv to contain the words, Fa argc to contain the number of words, Fa cursorc (if not NULL to contain the index of the word containing the cursor, and Fa cursoro (if not NULL to contain the offset within Fa argv[cursorc] of the cursor.

Returns 0 if successful, -1 for an internal error, 1 for an unmatched single quote, 2 for an unmatched double quote, and 3 for a backslash quoted Aq newline . A positive exit code indicates that another line should be read and tokenization attempted again.

Fn tok_str
A simpler form of Fn tok_line ; Fa str is a NUL terminated string to tokenize.

HISTORY

The library first appeared in BSD 4.4 CC_REDISPLAY appeared in Nx 1.3 . CC_REFRESH_BEEP EL_EDITMODE and the readline emulation appeared in Nx 1.4 . EL_RPROMPT appeared in Nx 1.5 .

AUTHORS

The library was written by Christos Zoulas. Luke Mewburn wrote this manual and implemented CC_REDISPLAY CC_REFRESH_BEEP EL_EDITMODE and EL_RPROMPT Jaromir Dolecek implemented the readline emulation.

BUGS

At this time, it is the responsibility of the caller to check the result of the EL_EDITMODE operation of Fn el_get (after an Fn el_source or Fn el_parse ) to determine if should be used for further input. I.e., EL_EDITMODE is purely an indication of the result of the most recent editrc(5) edit command.

SEE ALSO

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