Use the Perl interface to write the vim plug-in

Enable Perl before compiling Vim;

Use of Perl interface * perl-using *

                                                        *: perl * *: pe *
: pe [rl] {cmd} Execute Perl command {cmd}. The current package is "main".

: pe [rl] << {endpattern}
{script}
{endpattern}
                        Execute Perl script {script}.
                        {endpattern} cannot have any leading spaces. If {endpattern} is omitted,
                        You will reach a point '.' By default like the |: append | and |: insert | commands.
                        |: perl | This form of the command is mainly used to include the perl generation in the vim script
                        code.
                        Note: This command does not work when Perl is not compiled into vim. In order to avoid
                        To avoid errors, please refer to | script-here |.
vim script example:

        function! WhitePearl ()
        perl << EOF
                VIM :: Msg ("pearls are nice for necklaces");
                VIM :: Msg ("rubys for rings");
                VIM :: Msg ("pythons for bags");
                VIM :: Msg ("tcls ????");
        EOF
        endfunction


                                                        *: perldo * *: perld *
: [range] perld [o] {cmd} Execute the Perl command {cmd} on each line in [range], and $ _ is assigned in turn
                        For each line of text, excluding <EOL> at the end of the line. Changing $ _ will change every line
                        Content, but you cannot add or delete lines with this command. [range]
                        The default is the entire file: "1, $".

You can try the following code:

  : perl $ a = 1
  : perldo $ _ = reverse ($ _); 1
  : perl VIM :: Msg ("hello")
  : perl $ line = $ curbuf-> Get (42)


                                                        * E299 *
The execution of Perl commands in | sandbox | is restricted. ": perldo" simply cannot be executed. ": Perl" if possible
Will be executed in a secure environment.

                                                        * perl-overview *
Here is a summary of the functions available under Perl:

  : perl VIM :: Msg ("Text") # display information
  : perl VIM :: Msg ("Error", "ErrorMsg") # display error information
  : perl VIM :: Msg ("remark", "Comment") # Show highlighted information
  : perl VIM :: SetOption ("ai") # Set a vim option
  : perl $ nbuf = VIM :: Buffers () # returns the number of buffers
  : perl @buflist = VIM :: Buffers () # returns an array of all buffers
  : perl $ mybuf = (VIM :: Buffers ('qq.c')) [0] # Returns a buffer object of 'qq.c'
  : perl @winlist = VIM :: Windows () # returns an array of all windows
  : perl $ nwin = VIM :: Windows () # Returns the number of windows
  : perl ($ success, $ v) = VIM :: Eval ('& path') # $ v: option 'path', $ success: 1
  : perl ($ success, $ v) = VIM :: Eval ('& xyz') # $ v: '' and $ success: 0
  : perl $ v = VIM :: Eval ('expand ("<cfile>")') # expand file <cfile>
  : perl $ curwin-> SetHeight (10) # Set window height
  : perl @pos = $ curwin-> Cursor () # return coordinates (row, col)
  : perl @pos = (10, 10)
  : perl $ curwin-> Cursor (@pos) # Set the cursor position to @pos
  : perl $ curwin-> Cursor (10,10) # Set the cursor position to the 10th row and 10th column
  : perl $ mybuf = $ curwin-> Buffer () # returns the buffer object of the window
  : perl $ curbuf-> Name () # returns the buffer name
  : perl $ curbuf-> Number () # returns the buffer number
  : perl $ curbuf-> Count () # returns the number of rows
  : perl $ l = $ curbuf-> Get (10) # returns line 10
  : perl @l = $ curbuf-> Get (1 .. 5) # returns lines 1 to 5
  : perl $ curbuf-> Delete (10) # delete line 10
  : perl $ curbuf-> Delete (10, 20) # delete lines 10-20
  : perl $ curbuf-> Append (10, "Line") # add a line after line 10
  : perl $ curbuf-> Append (10, "Line1", "Line2", "Line3") # Add three lines after line 10
  : perl @l = ("L1", "L2", "L3")
  : perl $ curbuf-> Append (10, @l) # add L1, L2 and L3
  : perl $ curbuf-> Set (10, "Line") # replace line 10
  : perl $ curbuf-> Set (10, "Line1", "Line2") # Replace lines 10 and 11
  : perl $ curbuf-> Set (10, @l) # Replace lines 10-12 with L1, L2, and L3 respectively

                                                        * perl-Msg *
VIM :: Msg ((msg), (group)?)
                        The message {msg} is displayed. The optional {group} parameter specifies the
                        Prominent way.

                                                        * perl-SetOption *
VIM :: SetOption ((arg))
                        Set a vim option. {arg} can be any parameter accepted by the ": set" command.
                        This means that no spaces are allowed in the parameters! See |: set |.

                                                        * perl-Buffers *
VIM :: Buffers ([{bn} ...]) Without parameters, returns a list of all buffers in the list context
                        Or the number of buffers in a scalar context. For a buffer name
                        List or quantity {bn}, returns a list of buffers matching {bn}
                        The number | bufname () | uses the same rules.

                                                        * perl-Windows *
VIM :: Windows ([{wn} ...]) returns no list of all windows in the list context or
                        Returns the number of windows in a scalar context. For a list of window names (wn),
                        Returns a list of windows matching {wn}.

                                                        * perl-DoCommand *
VIM :: DoCommand ((cmd)) executes the Ex command (cmd).

                                                        * perl-Eval *
VIM :: Eval ({expr}) evaluates {expr} and returns (success, val). success = 1 means val contains {expr}
                        Value. success = 0 means the expression failed to evaluate. ‘@X’ returns the contents of register x,
                        '& x' returns the value of option x, 'x' returns the value of internal variable x, '$ x' is equivalent to that in fish perl
                        $ ENV {x}. All functions accessible from the command line are valid for {expr}.

                                                        * perl-SetHeight *
Window-> SetHeight ((height))
                        Set the height of the window to {height} if the screen allows it.

                                                        * perl-GetCursor *
Window-> Cursor ({row} ?, {col}?)
                        Without parameters, returns the coordinates (row, col) of the position of the window cursor.
                        With the parameters {row} and {col}, set the position of the window cursor to {row}
                        And {col}. Note that {col} is Perl-style, counting from 0, which is better than Vim's scale.
                        little 1.

Window-> Buffer ()
* perl-Buffer *
                        Returns the buffer object for the given window.

                                                        * perl-Name *
Buffer-> Name () Returns the file name of the buffer.

                                                        * perl-Number *
Buffer-> Number () Returns the number of buffers.

                                                        * perl-Count *
Buffer-> Count () Returns the number of rows in the buffer.

                                                        * perl-Get *
Buffer-> Get ({lnum}, {lnum} ?, ...)
                        For each specified (lnum), returns the text character at line (lnum) in the buffer
                        string. An array can be passed by specifying a {lnum} list.

                                                        * perl-Delete *
Buffer-> Delete ({lnum}, {lnum}?)
                        Delete the {lnum} line of the buffer. When there is a second parameter {lnum}, delete
                        The range specified by the first {lnum} to the second {lnum}.

                                                        * perl-Append *
Buffer-> Append ({lnum}, {line}, {line} ?, ...)
                        Add each {line} string after the {lnum} line of the buffer. {line}
                        The list can be an array.

                                                        * perl-Set *
Buffer-> Set ({lnum}, {line}, {line} ?, ...)
                        The replacement buffer starts at line {lnum}, one or more lines specified by {lines}.
                        The {line} list can be an array. If the parameter is invalid, it is not replaced.
$ main :: curwin
                        The current window object.
$ main :: curbuf
                        The current buffer object.

                                                        * script-here *
When using an embedded scripting language, you may want to skip these if the language is not supported. But this mechanism does not work:
   if has ('perl')
     perl << EOF
       this will NOT work!
   EOF
   endif
Instead, put commands such as Perl / Python / Ruby / in a function and call him:
    if has ('perl')
      function DefPerl ()
        perl << EOF
          this works
    EOF
      endfunction
      call DefPerl ()
    endif
Note: "EOF" must be at the beginning of the line (without leading spaces). 

Above from http://man.chinaunix.net/newsoft/vi/doc/if_perl.html

Think about how to use these APIs to write your own Vim plug-in.