zsh: ZLE Functions

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### 26.7 ZLE Functions

#### 26.7.1 Widgets

These functions all implement user-defined ZLE widgets (see Zsh Line Editor) which can be bound to keystrokes in interactive shells. To use them, your `.zshrc` should contain lines of the form

    autoload function
    zle -N function

followed by an appropriate `bindkey` command to associate the function with a key sequence. Suggested bindings are described below.

bash-style word functions

  If you are looking for functions to implement moving over and editing words in the manner of bash, where only alphanumeric characters are considered word characters, you can use the functions described in the next section. The following is sufficient:

      autoload -U select-word-style
      select-word-style bash

`forward-word-match`, `backward-word-match`
`kill-word-match`, `backward-kill-word-match`
`transpose-words-match`, `capitalize-word-match`
`up-case-word-match`, `down-case-word-match`
`select-word-style`, `match-word-context`, `match-words-by-style`

  The eight ‘`-match`’ functions are drop-in replacements for the builtin widgets without the suffix. By default they behave in a similar way. However, by the use of styles and the function `select-word-style`, the way words are matched can be altered. For comparison, the widgets described in Text Objects use fixed definitions of words, compatible with the `vim` editor.

  The simplest way of configuring the functions is to use `select-word-style`, which can either be called as a normal function with the appropriate argument, or invoked as a user-defined widget that will prompt for the first character of the word style to be used. The first time it is invoked, the eight `-match` functions will automatically replace the builtin versions, so they do not need to be loaded explicitly.

  The word styles available are as follows. Only the first character is examined.

  `bash`

    Word characters are alphanumeric characters only.

  `normal`

    As in normal shell operation: word characters are alphanumeric characters plus any characters present in the string given by the parameter `$WORDCHARS`.

  `shell`

    Words are complete shell command arguments, possibly including complete quoted strings, or any tokens special to the shell.

  `whitespace`

    Words are any set of characters delimited by whitespace.

  `default`

    Restore the default settings; this is usually the same as ‘`normal`’.

  All but ‘`default`’ can be input as an upper case character, which has the same effect but with subword matching turned on. In this case, words with upper case characters are treated specially: each separate run of upper case characters, or an upper case character followed by any number of other characters, is considered a word. The style `subword-range` can supply an alternative character range to the default ‘`[:upper:]`’; the value of the style is treated as the contents of a ‘`[`...`]`’ pattern (note that the outer brackets should not be supplied, only those surrounding named ranges).

  More control can be obtained using the `zstyle` command, as described in The zsh/zutil Module. Each style is looked up in the context `:zle:` widget where widget is the name of the user-defined widget, not the name of the function implementing it, so in the case of the definitions supplied by `select-word-style` the appropriate contexts are `:zle:forward-word`, and so on. The function `select-word-style` itself always defines styles for the context ‘`:zle:*`’ which can be overridden by more specific (longer) patterns as well as explicit contexts.

  The style `word-style` specifies the rules to use. This may have the following values.

  `normal`

    Use the standard shell rules, i.e. alphanumerics and `$WORDCHARS`, unless overridden by the styles `word-chars` or `word-class`.

  `specified`

    Similar to `normal`, but only the specified characters, and not also alphanumerics, are considered word characters.

  `unspecified`

    The negation of specified. The given characters are those which will not be considered part of a word.

  `shell`

    Words are obtained by using the syntactic rules for generating shell command arguments. In addition, special tokens which are never command arguments such as ‘`()`’ are also treated as words.

  `whitespace`

    Words are whitespace-delimited strings of characters.

  The first three of those rules usually use `$WORDCHARS`, but the value in the parameter can be overridden by the style `word-chars`, which works in exactly the same way as `$WORDCHARS`. In addition, the style `word-class` uses character class syntax to group characters and takes precedence over `word-chars` if both are set. The `word-class` style does not include the surrounding brackets of the character class; for example, ‘`-:[:alnum:]`’ is a valid `word-class` to include all alphanumerics plus the characters ‘`-`’ and ‘`:`’. Be careful including ‘`]`’, ‘`^`’ and ‘`-`’ as these are special inside character classes.

  `word-style` may also have ‘`-subword`’ appended to its value to turn on subword matching, as described above.

  The style `skip-chars` is mostly useful for `transpose-words` and similar functions. If set, it gives a count of characters starting at the cursor position which will not be considered part of the word and are treated as space, regardless of what they actually are. For example, if

      zstyle ':zle:transpose-words' skip-chars 1

  has been set, and `transpose-words-match` is called with the cursor on the X of `foo`X`bar`, where X can be any character, then the resulting expression is `bar`X`foo`.

  Finer grained control can be obtained by setting the style `word-context` to an array of pairs of entries. Each pair of entries consists of a pattern and a subcontext. The shell argument the cursor is on is matched against each pattern in turn until one matches; if it does, the context is extended by a colon and the corresponding subcontext. Note that the test is made against the original word on the line, with no stripping of quotes. Special handling is done between words: the current context is examined and if it contains the string `between` the word is set to a single space; else if it is contains the string `back`, the word before the cursor is considered, else the word after cursor is considered. Some examples are given below.

  The style `skip-whitespace-first` is only used with the `forward-word` widget. If it is set to true, then `forward-word` skips any non-word-characters, followed by any non-word-characters: this is similar to the behaviour of other word-orientated widgets, and also that used by other editors, however it differs from the standard zsh behaviour. When using `select-word-style` the widget is set in the context `:zle:*` to `true` if the word style is `bash` and `false` otherwise. It may be overridden by setting it in the more specific context `:zle:forward-word*`.

  Here are some examples of use of the styles, actually taken from the simplified interface in `select-word-style`:

      zstyle ':zle:*' word-style standard
      zstyle ':zle:*' word-chars {No value for `dsq'}

  Implements bash-style word handling for all widgets, i.e. only alphanumerics are word characters; equivalent to setting the parameter `WORDCHARS` empty for the given context.

      style ':zle:*kill*' word-style space

  Uses space-delimited words for widgets with the word ‘kill’ in the name. Neither of the styles `word-chars` nor `word-class` is used in this case.

  Here are some examples of use of the `word-context` style to extend the context.

      zstyle ':zle:*' word-context \
             "*/*" file "[[:space:]]" whitespace
      zstyle ':zle:transpose-words:whitespace' word-style shell
      zstyle ':zle:transpose-words:filename' word-style normal
      zstyle ':zle:transpose-words:filename' word-chars {No value for `dsq'}

  This provides two different ways of using `transpose-words` depending on whether the cursor is on whitespace between words or on a filename, here any word containing a `/`. On whitespace, complete arguments as defined by standard shell rules will be transposed. In a filename, only alphanumerics will be transposed. Elsewhere, words will be transposed using the default style for `:zle:transpose-words`.

  The word matching and all the handling of `zstyle` settings is actually implemented by the function `match-words-by-style`. This can be used to create new user-defined widgets. The calling function should set the local parameter `curcontext` to `:zle:` widget, create the local parameter `matched_words` and call `match-words-by-style` with no arguments. On return, `matched_words` will be set to an array with the elements: (1) the start of the line (2) the word before the cursor (3) any non-word characters between that word and the cursor (4) any non-word character at the cursor position plus any remaining non-word characters before the next word, including all characters specified by the `skip-chars` style, (5) the word at or following the cursor (6) any non-word characters following that word (7) the remainder of the line. Any of the elements may be an empty string; the calling function should test for this to decide whether it can perform its function.

  It is possible to pass options with arguments to `match-words-by-style` to override the use of styles. The options are:

  `-w`

    word-style

  `-s`

    skip-chars

  `-c`

    word-class

  `-C`

    word-chars

  `-r`

    subword-range

  For example, `match-words-by-style -w shell -c 0` may be used to extract the command argument around the cursor.

  The `word-context` style is implemented by the function `match-word-context`. This should not usually need to be called directly.

bracketed-paste-magic

  The `bracketed-paste` widget (see Miscellaneous in Zle Widgets) inserts pasted text literally into the editor buffer rather than interpret it as keystrokes. This disables some common usages where the self-insert widget is replaced in order to accomplish some extra processing. An example is the contributed `url-quote-magic` widget described below.

  The `bracketed-paste-magic` widget is meant to replace `bracketed-paste` with a wrapper that re-enables these self-insert actions, and other actions as selected by zstyles. Therefore this widget is installed with

      autoload -Uz bracketed-paste-magic
      zle -N bracketed-paste bracketed-paste-magic

  Other than enabling some widget processing, `bracketed-paste-magic` attempts to replicate `bracketed-paste` as faithfully as possible.

  The following zstyles may be set to control processing of pasted text. All are looked up in the context ‘`:bracketed-paste-magic`’.

  `active-widgets`

    A list of patterns matching widget names that should be activated during the paste. All other key sequences are processed as self-insert-unmeta. The default is ‘`self-*`’ so any user-defined widgets named with that prefix are active along with the builtin self-insert.

    If this style is not set (explicitly deleted) or set to an empty value, no widgets are active and the pasted text is inserted literally. If the value includes ‘`undefined-key`’, any unknown sequences are discarded from the pasted text.

  `inactive-keys`

    The inverse of `active-widgets`, a list of key sequences that always use `self-insert-unmeta` even when bound to an active widget. Note that this is a list of literal key sequences, not patterns.

  `paste-init`

    A list of function names, called in widget context (but not as widgets). The functions are called in order until one of them returns a non-zero status. The parameter ‘`PASTED`’ contains the initial state of the pasted text. All other ZLE parameters such as ‘`BUFFER`’ have their normal values and side-effects, and full history is available, so for example `paste-init` functions may move words from `BUFFER` into `PASTED` to make those words visible to the `active-widgets`.

    A non-zero return from a `paste-init` function does not prevent the paste itself from proceeding.

    Loading `bracketed-paste-magic` defines `backward-extend-paste`, a helper function for use in `paste-init`.

        zstyle :bracketed-paste-magic paste-init \
               backward-extend-paste

    When a paste would insert into the middle of a word or append text to a word already on the line, `backward-extend-paste` moves the prefix from `LBUFFER` into `PASTED` so that the `active-widgets` see the full word so far. This may be useful with `url-quote-magic`.

  `paste-finish`

    Another list of function names called in order until one returns non-zero. These functions are called after the pasted text has been processed by the `active-widgets`, but before it is inserted into ‘`BUFFER`’. ZLE parameters have their normal values and side-effects.

    A non-zero return from a `paste-finish` function does not prevent the paste itself from proceeding.

    Loading `bracketed-paste-magic` also defines `quote-paste`, a helper function for use in `paste-finish`.

        zstyle :bracketed-paste-magic paste-finish \
               quote-paste
        zstyle :bracketed-paste-magic:finish quote-style \
               qqq

    When the pasted text is inserted into `BUFFER`, it is quoted per the `quote-style` value. To forcibly turn off the built-in numeric prefix quoting of `bracketed-paste`, use:

        zstyle :bracketed-paste-magic:finish quote-style \
               none

  Important: During `active-widgets` processing of the paste (after `paste-init` and before `paste-finish`), `BUFFER` starts empty and history is restricted, so cursor motions, etc., may not pass outside of the pasted content. Text assigned to `BUFFER` by the active widgets is copied back into `PASTED` before `paste-finish`.

`copy-earlier-word`

  This widget works like a combination of `insert-last-word` and `copy-prev-shell-word`. Repeated invocations of the widget retrieve earlier words on the relevant history line. With a numeric argument N, insert the Nth word from the history line; N may be negative to count from the end of the line.

  If `insert-last-word` has been used to retrieve the last word on a previous history line, repeated invocations will replace that word with earlier words from the same line.

  Otherwise, the widget applies to words on the line currently being edited. The `widget` style can be set to the name of another widget that should be called to retrieve words. This widget must accept the same three arguments as `insert-last-word`.

`cycle-completion-positions`

  After inserting an unambiguous string into the command line, the new function based completion system may know about multiple places in this string where characters are missing or differ from at least one of the possible matches. It will then place the cursor on the position it considers to be the most interesting one, i.e. the one where one can disambiguate between as many matches as possible with as little typing as possible.

  This widget allows the cursor to be easily moved to the other interesting spots. It can be invoked repeatedly to cycle between all positions reported by the completion system.

`delete-whole-word-match`

  This is another function which works like the `-match` functions described immediately above, i.e. using styles to decide the word boundaries. However, it is not a replacement for any existing function.

  The basic behaviour is to delete the word around the cursor. There is no numeric argument handling; only the single word around the cursor is considered. If the widget contains the string `kill`, the removed text will be placed in the cutbuffer for future yanking. This can be obtained by defining `kill-whole-word-match` as follows:

      zle -N kill-whole-word-match delete-whole-word-match

  and then binding the widget `kill-whole-word-match`.

`up-line-or-beginning-search`, `down-line-or-beginning-search`

  These widgets are similar to the builtin functions `up-line-or-search` and `down-line-or-search`: if in a multiline buffer they move up or down within the buffer, otherwise they search for a history line matching the start of the current line. In this case, however, they search for a line which matches the current line up to the current cursor position, in the manner of `history-beginning-search-backward` and `-forward`, rather than the first word on the line.

`edit-command-line`

  Edit the command line using your visual editor, as in `ksh`.

      bindkey -M vicmd v edit-command-line

`expand-absolute-path`

  Expand the file name under the cursor to an absolute path, resolving symbolic links. Where possible, the initial path segment is turned into a named directory or reference to a user’s home directory.

`history-search-end`

  This function implements the widgets `history-beginning-search-backward-end` and `history-beginning-search-forward-end`. These commands work by first calling the corresponding builtin widget (see History Control) and then moving the cursor to the end of the line. The original cursor position is remembered and restored before calling the builtin widget a second time, so that the same search is repeated to look farther through the history.

  Although you `autoload` only one function, the commands to use it are slightly different because it implements two widgets.

      zle -N history-beginning-search-backward-end \
             history-search-end
      zle -N history-beginning-search-forward-end \
             history-search-end
      bindkey '\e^P' history-beginning-search-backward-end
      bindkey '\e^N' history-beginning-search-forward-end

`history-beginning-search-menu`

  This function implements yet another form of history searching. The text before the cursor is used to select lines from the history, as for `history-beginning-search-backward` except that all matches are shown in a numbered menu. Typing the appropriate digits inserts the full history line. Note that leading zeroes must be typed (they are only shown when necessary for removing ambiguity). The entire history is searched; there is no distinction between forwards and backwards.

  With a numeric argument, the search is not anchored to the start of the line; the string typed by the use may appear anywhere in the line in the history.

  If the widget name contains ‘`-end`’ the cursor is moved to the end of the line inserted. If the widget name contains ‘`-space`’ any space in the text typed is treated as a wildcard and can match anything (hence a leading space is equivalent to giving a numeric argument). Both forms can be combined, for example:

      zle -N history-beginning-search-menu-space-end \
             history-beginning-search-menu

`history-pattern-search`

  The function `history-pattern-search` implements widgets which prompt for a pattern with which to search the history backwards or forwards. The pattern is in the usual zsh format, however the first character may be `^` to anchor the search to the start of the line, and the last character may be `$` to anchor the search to the end of the line. If the search was not anchored to the end of the line the cursor is positioned just after the pattern found.

  The commands to create bindable widgets are similar to those in the example immediately above:

      autoload -U history-pattern-search
      zle -N history-pattern-search-backward history-pattern-search
      zle -N history-pattern-search-forward history-pattern-search

`incarg`

  Typing the keystrokes for this widget with the cursor placed on or to the left of an integer causes that integer to be incremented by one. With a numeric argument, the number is incremented by the amount of the argument (decremented if the numeric argument is negative). The shell parameter `incarg` may be set to change the default increment to something other than one.

      bindkey '^X+' incarg

`incremental-complete-word`

  This allows incremental completion of a word. After starting this command, a list of completion choices can be shown after every character you type, which you can delete with `^H` or `DEL`. Pressing return accepts the completion so far and returns you to normal editing (that is, the command line is not immediately executed). You can hit `TAB` to do normal completion, `^G` to abort back to the state when you started, and `^D` to list the matches.

  This works only with the new function based completion system.

      bindkey '^Xi' incremental-complete-word

`insert-composed-char`

  This function allows you to compose characters that don’t appear on the keyboard to be inserted into the command line. The command is followed by two keys corresponding to ASCII characters (there is no prompt). For accented characters, the two keys are a base character followed by a code for the accent, while for other special characters the two characters together form a mnemonic for the character to be inserted. The two-character codes are a subset of those given by RFC 1345 (see for example `http://www.faqs.org/rfcs/rfc1345.html`).

  The function may optionally be followed by up to two characters which replace one or both of the characters read from the keyboard; if both characters are supplied, no input is read. For example, `insert-composed-char a:` can be used within a widget to insert an a with umlaut into the command line. This has the advantages over use of a literal character that it is more portable.

  For best results zsh should have been built with support for multibyte characters (configured with `--enable-multibyte`); however, the function works for the limited range of characters available in single-byte character sets such as ISO-8859-1.

  The character is converted into the local representation and inserted into the command line at the cursor position. (The conversion is done within the shell, using whatever facilities the C library provides.) With a numeric argument, the character and its code are previewed in the status line

  The function may be run outside zle in which case it prints the character (together with a newline) to standard output. Input is still read from keystrokes.

  See `insert-unicode-char` for an alternative way of inserting Unicode characters using their hexadecimal character number.

  The set of accented characters is reasonably complete up to Unicode character U+0180, the set of special characters less so. However, it is very sporadic from that point. Adding new characters is easy, however; see the function `define-composed-chars`. Please send any additions to `zsh-workers@zsh.org`.

  The codes for the second character when used to accent the first are as follows. Note that not every character can take every accent.

  `!`

    Grave.

  `'`

    Acute.

  `>`

    Circumflex.

  `?`

    Tilde. (This is not `~` as RFC 1345 does not assume that character is present on the keyboard.)

  `-`

    Macron. (A horizontal bar over the base character.)

  `(`

    Breve. (A shallow dish shape over the base character.)

  `.`

    Dot above the base character, or in the case of `i` no dot, or in the case of `L` and `l` a centered dot.

  `:`

    Diaeresis (Umlaut).

  `c`

    Cedilla.

  `_`

    Underline, however there are currently no underlined characters.

  `/`

    Stroke through the base character.

  `"`

    Double acute (only supported on a few letters).

  `;`

    Ogonek. (A little forward facing hook at the bottom right of the character.)

  `<`

    Caron. (A little v over the letter.)

  `0`

    Circle over the base character.

  `2`

    Hook over the base character.

  `9`

    Horn over the base character.

  The most common characters from the Arabic, Cyrillic, Greek and Hebrew alphabets are available; consult RFC 1345 for the appropriate sequences. In addition, a set of two letter codes not in RFC 1345 are available for the double-width characters corresponding to ASCII characters from `!` to `~` (0x21 to 0x7e) by preceding the character with `^`, for example `^A` for a double-width `A`.

  The following other two-character sequences are understood.

  ASCII characters

    These are already present on most keyboards:

    `<(`

      Left square bracket

    `//`

      Backslash (solidus)

    `)>`

      Right square bracket

    `(!`

      Left brace (curly bracket)

    `!!`

      Vertical bar (pipe symbol)

    `!)`

      Right brace (curly bracket)

    `'?`

      Tilde

  Special letters

    Characters found in various variants of the Latin alphabet:

    `ss`

      Eszett (scharfes S)

    `D-`, `d-`

      Eth

    `TH`, `th`

      Thorn

    `kk`

      Kra

    `'n`

      ’n

    `NG`, `ng`

      Ng

    `OI`, `oi`

      Oi

    `yr`

      yr

    `ED`

      ezh

  Currency symbols
    `Ct`

      Cent

    `Pd`

      Pound sterling (also lira and others)

    `Cu`

      Currency

    `Ye`

      Yen

    `Eu`

      Euro (N.B. not in RFC 1345)

  Punctuation characters

    References to "right" quotes indicate the shape (like a 9 rather than 6) rather than their grammatical use. (For example, a "right" low double quote is used to open quotations in German.)

    `!I`

      Inverted exclamation mark

    `BB`

      Broken vertical bar

    `SE`

      Section

    `Co`

      Copyright

    `-a`

      Spanish feminine ordinal indicator

    `<<`

      Left guillemet

    `-``-`

      Soft hyphen

    `Rg`

      Registered trade mark

    `PI`

      Pilcrow (paragraph)

    `-o`

      Spanish masculine ordinal indicator

    `>>`

      Right guillemet

    `?I`

      Inverted question mark

    `-1`

      Hyphen

    `-N`

      En dash

    `-M`

      Em dash

    `-3`

      Horizontal bar

    `:3`

      Vertical ellipsis

    `.3`

      Horizontal midline ellipsis

    `!2`

      Double vertical line

    `=2`

      Double low line

    `'6`

      Left single quote

    `'9`

      Right single quote

    `.9`

      "Right" low quote

    `9'`

      Reversed "right" quote

    `"6`

      Left double quote

    `"9`

      Right double quote

    `:9`

      "Right" low double quote

    `9"`

      Reversed "right" double quote

    `/-`

      Dagger

    `/=`

      Double dagger

  Mathematical symbols
    `DG`

      Degree

    `-2`, `+-`, `-+`

      - sign, +/- sign, -/+ sign

    `2S`

      Superscript 2

    `3S`

      Superscript 3

    `1S`

      Superscript 1

    `My`

      Micro

    `.M`

      Middle dot

    `14`

      Quarter

    `12`

      Half

    `34`

      Three quarters

    `*X`

      Multiplication

    `-:`

      Division

    `%0`

      Per mille

    `FA`, `TE`, `/0`

      For all, there exists, empty set

    `dP`, `DE`, `NB`

      Partial derivative, delta (increment), del (nabla)

    `(-`, `-)`

      Element of, contains

    `*P`, `+Z`

      Product, sum

    `*-`, `Ob`, `Sb`

      Asterisk, ring, bullet

    `RT`, `0(`, `00`

      Root sign, proportional to, infinity

  Other symbols
    `cS`, `cH`, `cD`, `cC`

      Card suits: spades, hearts, diamonds, clubs

    `Md`, `M8`, `M2`, `Mb`, `Mx`, `MX`

      Musical notation: crotchet (quarter note), quaver (eighth note), semiquavers (sixteenth notes), flag sign, natural sign, sharp sign

    `Fm`, `Ml`

      Female, male

  Accents on their own
    `'>`

      Circumflex (same as caret, `^`)

    `'!`

      Grave (same as backtick, ```)

    `',`

      Cedilla

    `':`

      Diaeresis (Umlaut)

    `'m`

      Macron

    `''`

      Acute

`insert-files`

  This function allows you type a file pattern, and see the results of the expansion at each step. When you hit return, all expansions are inserted into the command line.

      bindkey '^Xf' insert-files

`insert-unicode-char`

  When first executed, the user inputs a set of hexadecimal digits. This is terminated with another call to `insert-unicode-char`. The digits are then turned into the corresponding Unicode character. For example, if the widget is bound to `^XU`, the character sequence ‘`^XU 4 c ^XU`’ inserts `L` (Unicode U+004c).

  See `insert-composed-char` for a way of inserting characters using a two-character mnemonic.

`narrow-to-region` [ `-p` pre ] [ `-P` post ]
`` [ `-S` statepm | `-R` statepm | [ `-l` lbufvar ] [ `-r` rbufvar ] ]
`` [ `-n` ] [ start end ]
`narrow-to-region-invisible`

  Narrow the editable portion of the buffer to the region between the cursor and the mark, which may be in either order. The region may not be empty.

  `narrow-to-region` may be used as a widget or called as a function from a user-defined widget; by default, the text outside the editable area remains visible. A `recursive-edit` is performed and the original widening status is then restored. Various options and arguments are available when it is called as a function.

  The options `-p` pretext and `-P` posttext may be used to replace the text before and after the display for the duration of the function; either or both may be an empty string.

  If the option `-n` is also given, pretext or posttext will only be inserted if there is text before or after the region respectively which will be made invisible.

  Two numeric arguments may be given which will be used instead of the cursor and mark positions.

  The option `-S` statepm is used to narrow according to the other options while saving the original state in the parameter with name statepm, while the option `-R` statepm is used to restore the state from the parameter; note in both cases the name of the parameter is required. In the second case, other options and arguments are irrelevant. When this method is used, no `recursive-edit` is performed; the calling widget should call this function with the option `-S`, perform its own editing on the command line or pass control to the user via ‘`zle recursive-edit`’, then call this function with the option `-R`. The argument statepm must be a suitable name for an ordinary parameter, except that parameters beginning with the prefix `_ntr_` are reserved for use within `narrow-to-region`. Typically the parameter will be local to the calling function.

  The options `-l` lbufvar and `-r` rbufvar may be used to specify parameters where the widget will store the resulting text from the operation. The parameter lbufvar will contain `LBUFFER` and rbufvar will contain `RBUFFER`. Neither of these two options may be used with `-S` or `-R`.

  `narrow-to-region-invisible` is a simple widget which calls `narrow-to-region` with arguments which replace any text outside the region with ‘`...`’. It does not take any arguments.

  The display is restored (and the widget returns) upon any zle command which would usually cause the line to be accepted or aborted. Hence an additional such command is required to accept or abort the current line.

  The return status of both widgets is zero if the line was accepted, else non-zero.

  Here is a trivial example of a widget using this feature.

      local state
      narrow-to-region -p $'Editing restricted region\n' \
        -P {No value for `dsq'} -S state
      zle recursive-edit
      narrow-to-region -R state

`predict-on`

  This set of functions implements predictive typing using history search. After `predict-on`, typing characters causes the editor to look backward in the history for the first line beginning with what you have typed so far. After `predict-off`, editing returns to normal for the line found. In fact, you often don’t even need to use `predict-off`, because if the line doesn’t match something in the history, adding a key performs standard completion, and then inserts itself if no completions were found. However, editing in the middle of a line is liable to confuse prediction; see the `toggle` style below.

  With the function based completion system (which is needed for this), you should be able to type `TAB` at almost any point to advance the cursor to the next {No value for ‘dsbq’}interesting{No value for ‘dsq’} character position (usually the end of the current word, but sometimes somewhere in the middle of the word). And of course as soon as the entire line is what you want, you can accept with return, without needing to move the cursor to the end first.

  The first time `predict-on` is used, it creates several additional widget functions:

  `delete-backward-and-predict`

    Replaces the `backward-delete-char` widget. You do not need to bind this yourself.

  `insert-and-predict`

    Implements predictive typing by replacing the `self-insert` widget. You do not need to bind this yourself.

  `predict-off`

    Turns off predictive typing.

  Although you `autoload` only the `predict-on` function, it is necessary to create a keybinding for `predict-off` as well.

      zle -N predict-on
      zle -N predict-off
      bindkey '^X^Z' predict-on
      bindkey '^Z' predict-off

`read-from-minibuffer`

  This is most useful when called as a function from inside a widget, but will work correctly as a widget in its own right. It prompts for a value below the current command line; a value may be input using all of the standard zle operations (and not merely the restricted set available when executing, for example, `execute-named-cmd`). The value is then returned to the calling function in the parameter `$REPLY` and the editing buffer restored to its previous state. If the read was aborted by a keyboard break (typically `^G`), the function returns status 1 and `$REPLY` is not set.

  If one argument is supplied to the function it is taken as a prompt, otherwise ‘`?` ’ is used. If two arguments are supplied, they are the prompt and the initial value of `$LBUFFER`, and if a third argument is given it is the initial value of `$RBUFFER`. This provides a default value and starting cursor placement. Upon return the entire buffer is the value of `$REPLY`.

  One option is available: ‘`-k` num’ specifies that num characters are to be read instead of a whole line. The line editor is not invoked recursively in this case, so depending on the terminal settings the input may not be visible, and only the input keys are placed in `$REPLY`, not the entire buffer. Note that unlike the `read` builtin num must be given; there is no default.

  The name is a slight misnomer, as in fact the shell’s own minibuffer is not used. Hence it is still possible to call `executed-named-cmd` and similar functions while reading a value.

`replace-argument`, `replace-argument-edit`

  The function `replace-argument` can be used to replace a command line argument in the current command line or, if the current command line is empty, in the last command line executed (the new command line is not executed). Arguments are as delimited by standard shell syntax,

  If a numeric argument is given, that specifies the argument to be replaced. 0 means the command name, as in history expansion. A negative numeric argument counts backward from the last word.

  If no numeric argument is given, the current argument is replaced; this is the last argument if the previous history line is being used.

  The function prompts for a replacement argument.

  If the widget contains the string `edit`, for example is defined as

      zle -N replace-argument-edit replace-argument

  then the function presents the current value of the argument for editing, otherwise the editing buffer for the replacement is initially empty.

`replace-string`, `replace-pattern`
`replace-string-again`, `replace-pattern-again`

  The function `replace-string` implements three widgets. If defined under the same name as the function, it prompts for two strings; the first (source) string will be replaced by the second everywhere it occurs in the line editing buffer.

  If the widget name contains the word ‘`pattern`’, for example by defining the widget using the command ‘`zle -N replace-pattern replace-string`’, then the matching is performed using zsh patterns. All zsh extended globbing patterns can be used in the source string; note that unlike filename generation the pattern does not need to match an entire word, nor do glob qualifiers have any effect. In addition, the replacement string can contain parameter or command substitutions. Furthermore, a ‘`&`’ in the replacement string will be replaced with the matched source string, and a backquoted digit ‘`\`N’ will be replaced by the Nth parenthesised expression matched. The form ‘`\{`N`}`’ may be used to protect the digit from following digits.

  If the widget instead contains the word ‘`regex`’ (or ‘`regexp`’), then the matching is performed using regular expressions, respecting the setting of the option `RE_MATCH_PCRE` (see the description of the function `regexp-replace` below). The special replacement facilities described above for pattern matching are available.

  By default the previous source or replacement string will not be offered for editing. However, this feature can be activated by setting the style `edit-previous` in the context `:zle:` widget (for example, `:zle:replace-string`) to `true`. In addition, a positive numeric argument forces the previous values to be offered, a negative or zero argument forces them not to be.

  The function `replace-string-again` can be used to repeat the previous replacement; no prompting is done. As with `replace-string`, if the name of the widget contains the word ‘`pattern`’ or ‘`regex`’, pattern or regular expression matching is performed, else a literal string replacement. Note that the previous source and replacement text are the same whether pattern, regular expression or string matching is used.

  In addition, `replace-string` shows the previous replacement above the prompt, so long as there was one during the current session; if the source string is empty, that replacement will be repeated without the widget prompting for a replacement string.

  For example, starting from the line:

      print This line contains fan and fond

  and invoking `replace-pattern` with the source string ‘`f(?)n`’ and the replacement string ‘`c\1r`’ produces the not very useful line:

      print This line contains car and cord

  The range of the replacement string can be limited by using the `narrow-to-region-invisible` widget. One limitation of the current version is that `undo` will cycle through changes to the replacement and source strings before undoing the replacement itself.

`send-invisible`

  This is similar to read-from-minibuffer in that it may be called as a function from a widget or as a widget of its own, and interactively reads input from the keyboard. However, the input being typed is concealed and a string of asterisks (‘`*`’) is shown instead. The value is saved in the parameter `$INVISIBLE` to which a reference is inserted into the editing buffer at the restored cursor position. If the read was aborted by a keyboard break (typically `^G`) or another escape from editing such as `push-line`, `$INVISIBLE` is set to empty and the original buffer is restored unchanged.

  If one argument is supplied to the function it is taken as a prompt, otherwise ‘`Non-echoed text:` ’ is used (as in emacs). If a second and third argument are supplied they are used to begin and end the reference to `$INVISIBLE` that is inserted into the buffer. The default is to open with `${`, then `INVISIBLE`, and close with `}`, but many other effects are possible.

`smart-insert-last-word`

  This function may replace the `insert-last-word` widget, like so:

      zle -N insert-last-word smart-insert-last-word

  With a numeric argument, or when passed command line arguments in a call from another widget, it behaves like `insert-last-word`, except that words in comments are ignored when `INTERACTIVE_COMMENTS` is set.

  Otherwise, the rightmost {No value for ‘dsbq’}interesting{No value for ‘dsq’} word from the previous command is found and inserted. The default definition of {No value for ‘dsbq’}interesting{No value for ‘dsq’} is that the word contains at least one alphabetic character, slash, or backslash. This definition may be overridden by use of the `match` style. The context used to look up the style is the widget name, so usually the context is `:insert-last-word`. However, you can bind this function to different widgets to use different patterns:

      zle -N insert-last-assignment smart-insert-last-word
      zstyle :insert-last-assignment match '[[:alpha:]][][[:alnum:]]#=*'
      bindkey '\e=' insert-last-assignment

  If no interesting word is found and the `auto-previous` style is set to a true value, the search continues upward through the history. When `auto-previous` is unset or false (the default), the widget must be invoked repeatedly in order to search earlier history lines.

`transpose-lines`

  Only useful with a multi-line editing buffer; the lines here are lines within the current on-screen buffer, not history lines. The effect is similar to the function of the same name in Emacs.

  Transpose the current line with the previous line and move the cursor to the start of the next line. Repeating this (which can be done by providing a positive numeric argument) has the effect of moving the line above the cursor down by a number of lines.

  With a negative numeric argument, requires two lines above the cursor. These two lines are transposed and the cursor moved to the start of the previous line. Using a numeric argument less than -1 has the effect of moving the line above the cursor up by minus that number of lines.

`url-quote-magic`

  This widget replaces the built-in `self-insert` to make it easier to type URLs as command line arguments. As you type, the input character is analyzed and, if it may need quoting, the current word is checked for a URI scheme. If one is found and the current word is not already in quotes, a backslash is inserted before the input character.

  Styles to control quoting behavior:

  `url-metas`

    This style is looked up in the context ‘`:url-quote-magic:` scheme’ (where scheme is that of the current URL, e.g. "`ftp`"). The value is a string listing the characters to be treated as globbing metacharacters when appearing in a URL using that scheme. The default is to quote all zsh extended globbing characters, excluding ’`<`’ and ’`>`’ but including braces (as in brace expansion). See also `url-seps`.

  `url-seps`

    Like `url-metas`, but lists characters that should be considered command separators, redirections, history references, etc. The default is to quote the standard set of shell separators, excluding those that overlap with the extended globbing characters, but including ’`<`’ and ’`>`’ and the first character of `$histchars`.

  `url-globbers`

    This style is looked up in the context ‘`:url-quote-magic`’. The values form a list of command names that are expected to do their own globbing on the URL string. This implies that they are aliased to use the ‘`noglob`’ modifier. When the first word on the line matches one of the values and the URL refers to a local file (see `url-local-schema`), only the `url-seps` characters are quoted; the `url-metas` are left alone, allowing them to affect command-line parsing, completion, etc. The default values are a literal ‘`noglob`’ plus (when the `zsh/parameter` module is available) any commands aliased to the helper function ‘`urlglobber`’ or its alias ‘`globurl`’.

  `url-local-schema`

    This style is always looked up in the context ‘`:urlglobber`’, even though it is used by both url-quote-magic and urlglobber. The values form a list of URI schema that should be treated as referring to local files by their real local path names, as opposed to files which are specified relative to a web-server-defined document root. The defaults are "`ftp`" and "`file`".

  `url-other-schema`

    Like `url-local-schema`, but lists all other URI schema upon which `urlglobber` and `url-quote-magic` should act. If the URI on the command line does not have a scheme appearing either in this list or in `url-local-schema`, it is not magically quoted. The default values are "`http`", "`https`", and "`ftp`". When a scheme appears both here and in `url-local-schema`, it is quoted differently depending on whether the command name appears in `url-globbers`.

  Loading `url-quote-magic` also defines a helper function ‘`urlglobber`’ and aliases ‘`globurl`’ to ‘`noglob urlglobber`’. This function takes a local URL apart, attempts to pattern-match the local file portion of the URL path, and then puts the results back into URL format again.

`which-command`

  This function is a drop-in replacement for the builtin widget `which-command`. It has enhanced behaviour, in that it correctly detects whether or not the command word needs to be expanded as an alias; if so, it continues tracing the command word from the expanded alias until it reaches the command that will be executed.

  The style `whence` is available in the context `:zle:$WIDGET`; this may be set to an array to give the command and options that will be used to investigate the command word found. The default is `whence -c`.

`zcalc-auto-insert`

  This function is useful together with the `zcalc` function described in Mathematical Functions. It should be bound to a key representing a binary operator such as ‘`+`’, ‘`-`’, ‘`*`’ or ‘`/`’. When running in zcalc, if the key occurs at the start of the line or immediately following an open parenthesis, the text `"ans "` is inserted before the representation of the key itself. This allows easy use of the answer from the previous calculation in the current line. The text to be inserted before the symbol typed can be modified by setting the variable `ZCALC_AUTO_INSERT_PREFIX`.

  Hence, for example, typing ‘`+12`’ followed by return adds 12 to the previous result.

  When not in zcalc, the key simply inserts the symbol itself.

#### 26.7.2 Utility Functions

These functions are useful in constructing widgets. They should be loaded with ‘`autoload -U` function’ and called as indicated from user-defined widgets.

`split-shell-arguments`

  This function splits the line currently being edited into shell arguments and whitespace. The result is stored in the array `reply`. The array contains all the parts of the line in order, starting with any whitespace before the first argument, and finishing with any whitespace after the last argument. Hence (so long as the option `KSH_ARRAYS` is not set) whitespace is given by odd indices in the array and arguments by even indices. Note that no stripping of quotes is done; joining together all the elements of `reply` in order is guaranteed to produce the original line.

  The parameter `REPLY` is set to the index of the word in `reply` which contains the character after the cursor, where the first element has index 1. The parameter `REPLY2` is set to the index of the character under the cursor in that word, where the first character has index 1.

  Hence `reply`, `REPLY` and `REPLY2` should all be made local to the enclosing function.

  See the function `modify-current-argument`, described below, for an example of how to call this function.

`modify-current-argument` [ expr-using-`$ARG` | func ]

  This function provides a simple method of allowing user-defined widgets to modify the command line argument under the cursor (or immediately to the left of the cursor if the cursor is between arguments).

  The argument can be an expression which when evaluated operates on the shell parameter `ARG`, which will have been set to the command line argument under the cursor. The expression should be suitably quoted to prevent it being evaluated too early.

  Alternatively, if the argument does not contain the string `ARG`, it is assumed to be a shell function, to which the current command line argument is passed as the only argument. The function should set the variable `REPLY` to the new value for the command line argument. If the function returns non-zero status, so does the calling function.

  For example, a user-defined widget containing the following code converts the characters in the argument under the cursor into all upper case:

      modify-current-argument '${(U)ARG}'

  The following strips any quoting from the current word (whether backslashes or one of the styles of quotes), and replaces it with single quoting throughout:

      modify-current-argument '${(qq)${(Q)ARG}}'

  The following performs directory expansion on the command line argument and replaces it by the absolute path:

      expand-dir() {
        REPLY=${~1}
        REPLY=${REPLY:a}
      }
      modify-current-argument expand-dir

  In practice the function `expand-dir` would probably not be defined within the widget where `modify-current-argument` is called.

#### 26.7.3 Styles

The behavior of several of the above widgets can be controlled by the use of the `zstyle` mechanism. In particular, widgets that interact with the completion system pass along their context to any completions that they invoke.

`break-keys`

  This style is used by the `incremental-complete-word` widget. Its value should be a pattern, and all keys matching this pattern will cause the widget to stop incremental completion without the key having any further effect. Like all styles used directly by `incremental-complete-word`, this style is looked up using the context ‘`:incremental`’.

`completer`

  The `incremental-complete-word` and `insert-and-predict` widgets set up their top-level context name before calling completion. This allows one to define different sets of completer functions for normal completion and for these widgets. For example, to use completion, approximation and correction for normal completion, completion and correction for incremental completion and only completion for prediction one could use:

      zstyle ':completion:*' completer \
              _complete _correct _approximate
      zstyle ':completion:incremental:*' completer \
              _complete _correct
      zstyle ':completion:predict:*' completer \
              _complete

  It is a good idea to restrict the completers used in prediction, because they may be automatically invoked as you type. The `_list` and `_menu` completers should never be used with prediction. The `_approximate`, `_correct`, `_expand`, and `_match` completers may be used, but be aware that they may change characters anywhere in the word behind the cursor, so you need to watch carefully that the result is what you intended.

`cursor`

  The `insert-and-predict` widget uses this style, in the context ‘`:predict`’, to decide where to place the cursor after completion has been tried. Values are:

  `complete`

    The cursor is left where it was when completion finished, but only if it is after a character equal to the one just inserted by the user. If it is after another character, this value is the same as ‘`key`’.

  `key`

    The cursor is left after the nth occurrence of the character just inserted, where n is the number of times that character appeared in the word before completion was attempted. In short, this has the effect of leaving the cursor after the character just typed even if the completion code found out that no other characters need to be inserted at that position.

  Any other value for this style unconditionally leaves the cursor at the position where the completion code left it.

`list`

  When using the `incremental-complete-word` widget, this style says if the matches should be listed on every key press (if they fit on the screen). Use the context prefix ‘`:completion:incremental`’.

  The `insert-and-predict` widget uses this style to decide if the completion should be shown even if there is only one possible completion. This is done if the value of this style is the string `always`. In this case the context is ‘`:predict`’ (not ‘`:completion:predict`’).

`match`

  This style is used by `smart-insert-last-word` to provide a pattern (using full `EXTENDED_GLOB` syntax) that matches an interesting word. The context is the name of the widget to which `smart-insert-last-word` is bound (see above). The default behavior of `smart-insert-last-word` is equivalent to:

      zstyle :insert-last-word match '*[[:alpha:]/\\]*'

  However, you might want to include words that contain spaces:

      zstyle :insert-last-word match '*[[:alpha:][:space:]/\\]*'

  Or include numbers as long as the word is at least two characters long:

      zstyle :insert-last-word match '*([[:digit:]]?|[[:alpha:]/\\])*'

  The above example causes redirections like "2>" to be included.

`prompt`

  The `incremental-complete-word` widget shows the value of this style in the status line during incremental completion. The string value may contain any of the following substrings in the manner of the `PS1` and other prompt parameters:

  `%c`

    Replaced by the name of the completer function that generated the matches (without the leading underscore).

  `%l`

    When the `list` style is set, replaced by ‘`...`’ if the list of matches is too long to fit on the screen and with an empty string otherwise. If the `list` style is ‘false’ or not set, ‘`%l`’ is always removed.

  `%n`

    Replaced by the number of matches generated.

  `%s`

    Replaced by ‘`-no match-`’, ‘`-no prefix-`’, or an empty string if there is no completion matching the word on the line, if the matches have no common prefix different from the word on the line, or if there is such a common prefix, respectively.

  `%u`

    Replaced by the unambiguous part of all matches, if there is any, and if it is different from the word on the line.

  Like ‘`break-keys`’, this uses the ‘`:incremental`’ context.

`stop-keys`

  This style is used by the `incremental-complete-word` widget. Its value is treated similarly to the one for the `break-keys` style (and uses the same context: ‘`:incremental`’). However, in this case all keys matching the pattern given as its value will stop incremental completion and will then execute their usual function.

`toggle`

  This boolean style is used by `predict-on` and its related widgets in the context ‘`:predict`’. If set to one of the standard ‘true’ values, predictive typing is automatically toggled off in situations where it is unlikely to be useful, such as when editing a multi-line buffer or after moving into the middle of a line and then deleting a character. The default is to leave prediction turned on until an explicit call to `predict-off`.

`verbose`

  This boolean style is used by `predict-on` and its related widgets in the context ‘`:predict`’. If set to one of the standard ‘true’ values, these widgets display a message below the prompt when the predictive state is toggled. This is most useful in combination with the `toggle` style. The default does not display these messages.

`widget`

  This style is similar to the `command` style: For widget functions that use `zle` to call other widgets, this style can sometimes be used to override the widget which is called. The context for this style is the name of the calling widget (not the name of the calling function, because one function may be bound to multiple widget names).

      zstyle :copy-earlier-word widget smart-insert-last-word

  Check the documentation for the calling widget or function to determine whether the `widget` style is used.

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