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if_ruby - Vim Documentation

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if_ruby.txt   For Vim version 8.1.  Last change: 2019 May 05

                  VIM REFERENCE MANUAL    by Shugo Maeda

The Ruby Interface to Vim                               ruby Ruby

1. Commands                     ruby-commands
2. The Vim module               ruby-vim
3. Vim::Buffer objects          ruby-buffer
4. Vim::Window objects          ruby-window
5. Global variables             ruby-globals
6. rubyeval() Vim function      ruby-rubyeval
7. Dynamic loading              ruby-dynamic

                        E266 E267 E268 E269 E270 E271 E272 E273

{only available when Vim was compiled with the +ruby feature}

The home page for ruby is  You can find links for
downloading Ruby there.

1. Commands                                             ruby-commands

                                                        :ruby :rub
:rub[y] {cmd}           Execute Ruby command {cmd}.  A command to try it out:
                                :ruby print "Hello"

:rub[y] << {endpattern}
                        Execute Ruby script {script}.
                        {endpattern} must NOT be preceded by any white space.
                        If {endpattern} is omitted, it defaults to a dot '.'
                        like for the :append and :insert commands.  This
                        form of the :ruby command is mainly useful for
                        including ruby code in vim scripts.
                        Note: This command doesn't work when the Ruby feature
                        wasn't compiled in.  To avoid errors, see

Example Vim script:

        function! RedGem()
        ruby << EOF
        class Garnet
                def initialize(s)
                        @buffer = Vim::Buffer.current
                def vimputs(s)
        gem ="pretty")

To see what version of Ruby you have:
        :ruby print RUBY_VERSION

                                                :rubydo :rubyd E265
:[range]rubyd[o] {cmd}  Evaluate Ruby command {cmd} for each line in the
                        [range], with $_ being set to the text of each line in
                        turn, without a trailing <EOL>.  Setting $_ will change
                        the text, but note that it is not possible to add or
                        delete lines using this command.
                        The default for [range] is the whole file: "1,$".

                                                        :rubyfile :rubyf
:rubyf[ile] {file}      Execute the Ruby script in {file}.  This is the same as
                        :ruby load 'file', but allows file name completion.

Executing Ruby commands is not possible in the sandbox.

2. The Vim module                                       ruby-vim

Ruby code gets all of its access to vim via the "Vim" module.

        print "Hello"                         # displays a message
        Vim.command(cmd)                      # execute an Ex command
        num = Vim::Window.count               # gets the number of windows
        w = Vim::Window[n]                    # gets window "n"
        cw = Vim::Window.current              # gets the current window
        num = Vim::Buffer.count               # gets the number of buffers
        b = Vim::Buffer[n]                    # gets buffer "n"
        cb = Vim::Buffer.current              # gets the current buffer
        w.height = lines                      # sets the window height
        w.cursor = [row, col]                 # sets the window cursor position
        pos = w.cursor                        # gets an array [row, col]
        name =                         # gets the buffer file name
        line = b[n]                           # gets a line from the buffer
        num = b.count                         # gets the number of lines
        b[n] = str                            # sets a line in the buffer
        b.delete(n)                           # deletes a line
        b.append(n, str)                      # appends a line after n
        line = Vim::Buffer.current.line       # gets the current line
        num = Vim::Buffer.current.line_number # gets the current line number
        Vim::Buffer.current.line = "test"     # sets the current line number

Module Functions:

        Displays the message {msg}.

        Return Blob literal string from {arg}.

        Sets a vim option.  {arg} can be any argument that the ":set" command
        accepts.  Note that this means that no spaces are allowed in the
        argument!  See :set.

        Executes Ex command {cmd}.

        Evaluates {expr} using the vim internal expression evaluator (see
        expression).  Returns the expression result as:
        - a Integer if the Vim expression evaluates to a number
        - a Float if the Vim expression evaluates to a float
        - a String if the Vim expression evaluates to a string
        - a Array if the Vim expression evaluates to a Vim list
        - a Hash if the Vim expression evaluates to a Vim dictionary
        Dictionaries and lists are recursively expanded.

3. Vim::Buffer objects                                  ruby-buffer

Vim::Buffer objects represent vim buffers.

Class Methods:

current         Returns the current buffer object.
count           Returns the number of buffers.
self[{n}]       Returns the buffer object for the number {n}.  The first number
                is 0.


name            Returns the full name of the buffer.
number          Returns the number of the buffer.
count           Returns the number of lines.
length          Returns the number of lines.
self[{n}]       Returns a line from the buffer. {n} is the line number.
self[{n}] = {str}
                Sets a line in the buffer. {n} is the line number.
delete({n})     Deletes a line from the buffer. {n} is the line number.
                Appends a line after the line {n}.
line            Returns the current line of the buffer if the buffer is
line = {str}    Sets the current line of the buffer if the buffer is active.
line_number     Returns the number of the current line if the buffer is

4. Vim::Window objects                                  ruby-window

Vim::Window objects represent vim windows.

Class Methods:

current         Returns the current window object.
count           Returns the number of windows.
self[{n}]       Returns the window object for the number {n}.  The first number
                is 0.


buffer          Returns the buffer displayed in the window.
height          Returns the height of the window.
height = {n}    Sets the window height to {n}.
width           Returns the width of the window.
width = {n}     Sets the window width to {n}.
cursor          Returns a [row, col] array for the cursor position.
                First line number is 1 and first column number is 0.
cursor = [{row}{col}]
                Sets the cursor position to {row} and {col}.

5. Global variables                                     ruby-globals

There are two global variables.

$curwin         The current window object.
$curbuf         The current buffer object.

6. rubyeval() Vim function                              ruby-rubyeval

To facilitate bi-directional interface, you can use rubyeval() function to
evaluate Ruby expressions and pass their values to Vim script.

The Ruby value "true", "false" and "nil" are converted to v:true, v:false and
v:null, respectively.

7. Dynamic loading                                      ruby-dynamic

On MS-Windows and Unix the Ruby library can be loaded dynamically.  The
:version output then includes +ruby/dyn.

This means that Vim will search for the Ruby DLL file or shared library only
when needed.  When you don't use the Ruby interface you don't need it, thus
you can use Vim even though this library file is not on your system.


You need to install the right version of Ruby for this to work.  You can find
the package to download from:
Currently that is rubyinstaller-2.2.5.exe

To use the Ruby interface the Ruby DLL must be in your search path.  In a
console window type "path" to see what directories are used.  The 'rubydll'
option can be also used to specify the Ruby DLL.

The name of the DLL must match the Ruby version Vim was compiled with.
Currently the name is "msvcrt-ruby220.dll".  That is for Ruby 2.2.X.  To know
for sure edit "gvim.exe" and search for "ruby\d*.dll\c".

If you want to build Vim with RubyInstaller 1.9 or 2.X using MSVC, you need
some tricks.  See the src/INSTALLpc.txt for detail.

If Vim is built with RubyInstaller 2.4 or later, you may also need to add
"C:\Ruby<version>\bin\ruby_builtin_dlls" to the PATH environment variable.


The 'rubydll' option can be used to specify the Ruby shared library file
instead of DYNAMIC_RUBY_DLL file what was specified at compile time.  The
version of the shared library must match the Ruby version Vim was compiled