April 5, 2008

### NAME

editline, el_init, el_end, el_reset, el_gets, el_getc, el_push, el_parse, el_set, el_get, 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 - line editor, history and tokenization functions

### LIBRARY

Command Line Editor Library (libedit, -ledit)

### SYNOPSIS

```EditLine``*` el_init(```const char *prog``, FILE *fin``, FILE *fout``, FILE *ferr`)
```void` el_end(```EditLine *e`)
```void` el_reset(```EditLine *e`)
```const` `char``*` el_gets(```EditLine *e``, int *count`)
```int` el_getc(```EditLine *e``, char *ch`)
```void` el_push(```EditLine *e``, const char *str`)
```int` el_parse(```EditLine *e``, int argc``, const char *argv[]`)
```int` el_set(```EditLine *e``, int op``, ...`)
```int` el_get(```EditLine *e``, int op``, ...`)
```int` el_source(```EditLine *e``, const char *file`)
```void` el_resize(```EditLine *e`)
```const` `LineInfo``*` el_line(```EditLine *e`)
```int` el_insertstr(```EditLine *e``, const char *str`)
```void` el_deletestr(```EditLine *e``, int count`)
```History``*` history_init(``)
```void` history_end(```History *h`)
```int` history(```History *h``, HistEvent *ev``, int op``, ...`)
```Tokenizer``*` tok_init(```const char *IFS`)
```void` tok_end(```Tokenizer *t`)
```void` tok_reset(```Tokenizer *t`)
```int` tok_line(```Tokenizer *t``, const LineInfo *li``, int *argc``, const char **argv[]``, int *cursorc``, int *cursoro`)
```int` tok_str(```Tokenizer *t``, const char *str``, int *argc``, const char **argv[]`)

### DESCRIPTION

The editline 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, ```EditLine`, which is created by el_init(``) and freed by el_end(``).

The following functions are available:

el_init(``)
  Initialise the line editor, and return a data structure to be used by all other line editing functions. ```prog` is the name of the invoking program, used when reading the editrc(5) file to determine which settings to use. ```fin`, ```fout` and ```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.

el_end(``)
  Clean up and finish with ```e`, assumed to have been created with el_init(``).

el_reset(``)
  Reset the tty and the parser. This should be called after an error which may have upset the tty's state.

el_gets(``)
  Read a line from the tty. ```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.

el_getc(``)
  Read a character from the tty. ```ch` is modified to contain the character read. Returns the number of characters read if successful, -1 otherwise.

el_push(``)
  Pushes ```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.

el_parse(``)
  Parses the ```argv` array (which is ```argc` elements in size) to execute builtin editline commands. If the command is prefixed with ``prog'': then el_parse(``) will only execute the command if ``prog'' matches the ```prog` argument supplied to 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.

el_set(``)
  Set editline parameters. ```op` determines which parameter to set, and each operation has its own parameter list.

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

  ```EL_PROMPT```,`char *(*f)(EditLine *)`
    Define prompt printing function as ```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```,`char *(*f)(EditLine *)`
    Define right side prompt printing function as ```f`, which is to return a string that contains the prompt.

  ```EL_TERMINAL```,`const char *type`
    Define terminal type of the tty to be ```type`, or to ```TERM` if ```type` is ```NULL`.

  ```EL_EDITOR```,`const char *mode`
    Set editing mode to ```mode`, which must be one of ``emacs'' or ``vi''.

  ```EL_SIGNAL```,`int flag`
    If ```flag` is non-zero, editline 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`,`Xo`
    ```const char *`, ```...`, ```NULL` Perform the bind builtin command. Refer to editrc(5) for more information.

  ```EL_ECHOTC`,`Xo`
    ```const char *`, ```...`, ```NULL` Perform the echotc builtin command. Refer to editrc(5) for more information.

  ```EL_SETTC`,`Xo`
    ```const char *`, ```...`, ```NULL` Perform the settc builtin command. Refer to editrc(5) for more information.

  ```EL_SETTY`,`Xo`
    ```const char *`, ```...`, ```NULL` Perform the setty builtin command. Refer to editrc(5) for more information.

  ```EL_TELLTC`,`Xo`
    ```const char *`, ```...`, ```NULL` Perform the telltc builtin command. Refer to editrc(5) for more information.

  ```EL_ADDFN`,`Xo`
    ```const char *name`, ```const char *help`, ```unsigned char (*func)(EditLine *e, int ch)` Add a user defined function, func(``), referred to as ```name` which is invoked when a key which is bound to ```name` is entered. ```help` is a description of ```name`. At invocation time, ```ch` is the key which caused the invocation. The return value of 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`,`Xo`
    ```History *(*func)(History *, int op, ...)`, ```const char *ptr` Defines which history function to use, which is usually history(``). ```ptr` should be the value returned by history_init(``).

  ```EL_EDITMODE```,`int flag`
    If ```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 el_get(``)) to determine if editing should be enabled or not.

  ```EL_GETCFN```,`int (*f)(EditLine *, char *c)`
    Define the character reading function as ```f`, which is to return the number of characters read and store them in ```c`. This function is called internally by el_gets(``) and el_getc(``). The builtin function can be set or restored with the special function name ``EL_BUILTIN_GETCFN''.

  ```EL_CLIENTDATA```,`void *data`
    Register ```data` to be associated with this EditLine structure. It can be retrieved with the corresponding el_get(``) call.

  ```EL_SETFP```,`int fd```,`FILE *fp`
    Set the current editline file pointer for ``input'' ```fd` = ```0`, ``output'' ```fd` = ```1`, or ``error'' ```fd` = ```2` from ```fp`.

el_get(``)
  Get editline parameters. ```op` determines which parameter to retrieve into ```result`. Returns 0 if successful, -1 otherwise.

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

  ```EL_PROMPT```,`char *(*f)(EditLine *)`
    Return a pointer to the function that displays the prompt.

  ```EL_RPROMPT```,`char *(*f)(EditLine *)`
    Return a pointer to the function that displays the rightside prompt.

  ```EL_EDITOR```,`const char *`
    Return the name of the editor, which will be one of ``emacs'' or ``vi''.

  ```EL_GETTC```,`const char *name```,`void *value`
    Return non-zero if ```name` is a valid termcap(5) capability and set ```value` to the current value of that capability.

  ```EL_SIGNAL```,`int *`
    Return non-zero if editline has installed private signal handlers (see el_get(``) above).

  ```EL_EDITMODE```,`int *`
    Return non-zero if editing is enabled.

  ```EL_GETCFN```,`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```,`void **data`
    Retrieve ```data` previously registered with the corresponding el_set(``) call.

  ```EL_UNBUFFERED```,`int`
    Sets or clears unbuffered mode. In this mode, el_gets(``) will return immediately after processing a single character.

  ```EL_PREP_TERM```,`int`
    Sets or clears terminal editing mode.

  ```EL_GETFP```,`int fd```,`FILE **fp`
    Return in ```fp` the current editline file pointer for ``input'' ```fd` = ```0`, ``output'' ```fd` = ```1`, or ``error'' ```fd` = ```2`.

el_source(``)
  Initialise editline by reading the contents of ```file`. el_parse(``) is called for each line in ```file`. If ```file` is ```NULL`, try ```$PWD/.editrc` then ```$HOME/.editrc`. Refer to editrc(5) for details on the format of ```file`.

el_resize(``)
  Must be called if the terminal size changes. If ```EL_SIGNAL` has been set with el_set(``), then this is done automatically. Otherwise, it's the responsibility of the application to call el_resize(``) on the appropriate occasions.

el_line(``)
  Return the editing information for the current line in a ```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;

  `

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

el_insertstr(``)
  Insert ```str` into the line at the cursor. Returns -1 if ```str` is empty or won't fit, and 0 otherwise.

el_deletestr(``)
  Delete ```count` characters before the cursor.

### HISTORY LIST FUNCTIONS

The history functions use a common data structure, ```History`, which is created by history_init(``) and freed by history_end(``).

The following functions are available:

history_init(``)
  Initialise the history list, and return a data structure to be used by all other history list functions.

history_end(``)
  Clean up and finish with ```h`, assumed to have been created with history_init(``).

history(``)
  Perform operation ```op` on the history list, with optional arguments as needed by the operation. ```ev` is changed accordingly to operation. The following values for ```op` are supported, along with the required argument list:

  ```H_SETSIZE```,`int size`
    Set size of history to ```size` elements.

  ```H_GETSIZE`
    Get number of events currently in history.

  ```H_END`
    Cleans up and finishes with ```h`, assumed to be created with history_init(``).

  ```H_CLEAR`
    Clear the history.

  ```H_FUNC`,`Xo`
    ```void *ptr`, ```history_gfun_t first`, ```history_gfun_t next`, ```history_gfun_t last`, ```history_gfun_t prev`, ```history_gfun_t curr`, ```history_sfun_t set`, ```history_vfun_t clear`, ```history_efun_t enter`, ```history_efun_t add` Define functions to perform various history operations. ```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```,`const char *str`
    Append ```str` to the current element of the history, or perform the ```H_ENTER` operation with argument ```str` if there is no current element.

  ```H_APPEND```,`const char *str`
    Append ```str` to the last new element of the history.

  ```H_ENTER```,`const char *str`
    Add ```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 history(``) returns 1, if it is ignored as a duplicate returns 0. Finally history(``) returns -1 if an error occurred.

  ```H_PREV_STR```,`const char *str`
    Return the closest previous event that starts with ```str`.

  ```H_NEXT_STR```,`const char *str`
    Return the closest next event that starts with ```str`.

  ```H_PREV_EVENT```,`int e`
    Return the previous event numbered ```e`.

  ```H_NEXT_EVENT```,`int e`
    Return the next event numbered ```e`.

  ```H_LOAD```,`const char *file`
    Load the history list stored in ```file`.

  ```H_SAVE```,`const char *file`
    Save the history list to ```file`.

  ```H_SETUNIQUE```,`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```,`int e`
    Delete the event numbered ```e`. This function is only provided for readline(3) compatibility. The caller is responsible for free'ing the string in the returned ```HistEvent`.

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

### TOKENIZATION FUNCTIONS

The tokenization functions use a common data structure, ```Tokenizer`, which is created by tok_init(``) and freed by tok_end(``).

The following functions are available:

tok_init(``)
  Initialise the tokenizer, and return a data structure to be used by all other tokenizer functions. ```IFS` contains the Input Field Separators, which defaults to <space>, <tab>, and <newline> if ```NULL`.

tok_end(``)
  Clean up and finish with ```t`, assumed to have been created with tok_init(``).

tok_reset(``)
  Reset the tokenizer state. Use after a line has been successfully tokenized by tok_line(``) or tok_str(``) and before a new line is to be tokenized.

tok_line(``)
  Tokenize ```li`, If successful, modify: ```argv` to contain the words, ```argc` to contain the number of words, ```cursorc` (if not ```NULL`) to contain the index of the word containing the cursor, and ```cursoro` (if not ```NULL`) to contain the offset within ```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 <newline>. A positive exit code indicates that another line should be read and tokenization attempted again.

tok_str(``)
  A simpler form of tok_line(``); ```str` is a NUL terminated string to tokenize.

### SEE ALSO

sh(1), signal(3), termcap(3), editrc(5), termcap(5)

### HISTORY

The editline library first appeared in 4.4BSD. ```CC_REDISPLAY` appeared in NetBSD1.3. ```CC_REFRESH_BEEP`, ```EL_EDITMODE` and the readline emulation appeared in NetBSD1.4. ```EL_RPROMPT` appeared in NetBSD1.5.

### AUTHORS

The editline 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 el_get(``) (after an el_source(``) or el_parse(``)) to determine if editline 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.