# Vim documentation: if_mzsch

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    *if_mzsch.txt*  For Vim version 8.2.  Last change: 2019 Dec 07

    		  VIM REFERENCE MANUAL    by Sergey Khorev

    The MzScheme Interface to Vim				*mzscheme* *MzScheme*

    1. Commands				|mzscheme-commands|
    2. Examples				|mzscheme-examples|
    3. Threads				|mzscheme-threads|
    4. Vim access from MzScheme		|mzscheme-vim|
    5. mzeval() Vim function		|mzscheme-mzeval|
    6. Using Function references		|mzscheme-funcref|
    7. Dynamic loading			|mzscheme-dynamic|
    8. MzScheme setup			|mzscheme-setup|

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

    Based on the work of Brent Fulgham.
    Dynamic loading added by Sergey Khorev

    MzScheme and PLT Scheme names have been rebranded as Racket. For more
     information please check	http://racket-lang.org

    Futures and places of Racket version 5.x up to and including 5.3.1 do not
    work correctly with processes created by Vim.
    The simplest solution is to build Racket on your own with these features
    disabled:
      ./configure --disable-futures --disable-places --prefix=your-install-prefix

    To speed up the process, you might also want to use --disable-gracket and
    --disable-docs

    ==============================================================================

    1. Commands						*mzscheme-commands*

    							*:mzscheme* *:mz*
    :[range]mz[scheme] {stmt}
    			Execute MzScheme statement {stmt}.

    :[range]mz[scheme] << [endmarker]
    {script}
    {endmarker}
    			Execute inlined MzScheme script {script}.
    			Note: This command doesn't work if the MzScheme
    			feature wasn't compiled in.  To avoid errors, see
    			|script-here|.

    			The {endmarker} below the {script} must NOT be
    			preceded by any white space.

    			If [endmarker] is omitted from after the "<<", a dot
    			'.' must be used after {script}, like for the
    			|:append| and |:insert| commands.

    							*:mzfile* *:mzf*
    :[range]mzf[ile] {file}	Execute the MzScheme script in {file}.

    All of these commands do essentially the same thing - they execute a piece of
    MzScheme code, with the "current range" set to the given line
    range.

    In the case of :mzscheme, the code to execute is in the command-line.
    In the case of :mzfile, the code to execute is the contents of the given file.

    MzScheme interface defines exception exn:vim, derived from exn.
    It is raised for various Vim errors.

    During compilation, the MzScheme interface will remember the current MzScheme
    collection path. If you want to specify additional paths use the
    'current-library-collection-paths' parameter. E.g., to cons the user-local
    MzScheme collection path:
        :mz << EOF
        (current-library-collection-paths
    	(cons
    	    (build-path (find-system-path 'addon-dir) (version) "collects")
    	    (current-library-collection-paths)))
        EOF

    All functionality is provided through module vimext.

    The exn:vim is available without explicit import.

    To avoid clashes with MzScheme, consider using prefix when requiring module,
    e.g.:
    	:mzscheme (require (prefix vim- vimext))

    All the examples below assume this naming scheme.

    							*mzscheme-sandbox*
    When executed in the |sandbox|, access to some filesystem and Vim interface
    procedures is restricted.

    ==============================================================================

    2. Examples						*mzscheme-examples*

    	:mzscheme (display "Hello")
    	:mz (display (string-append "Using MzScheme version " (version)))
    	:mzscheme (require (prefix vim- vimext)) ; for MzScheme < 4.x
    	:mzscheme (require (prefix-in vim- 'vimext)) ; MzScheme 4.x
    	:mzscheme (vim-set-buff-line 10 "This is line #10")

    To see what version of MzScheme you have:
    	:mzscheme (display (version))

    Inline script usage:
    	function! <SID>SetFirstLine()
    	    :mz << EOF
    	    (display "!!!")
    	    (require (prefix vim- vimext))
    	    ; for newer versions (require (prefix-in vim- 'vimext))
    	    (vim-set-buff-line 1 "This is line #1")
    	    (vim-beep)
    	EOF
    	endfunction

    	nmap <F9> :call <SID>SetFirstLine() <CR>

    File execution:
    	:mzfile supascript.scm

    Vim exception handling:
    	:mz << EOF
    	(require (prefix vim- vimext))
    	; for newer versions (require (prefix-in vim- 'vimext))
    	(with-handlers
    	  ([exn:vim? (lambda (e) (display (exn-message e)))])
    	  (vim-eval "nonsense-string"))
    	EOF

    Auto-instantiation of vimext module (can be placed in your |vimrc|):
        function! MzRequire()
    	:redir => l:mzversion
    	:mz (version)
    	:redir END
    	if strpart(l:mzversion, 1, 1) < "4"
    	    " MzScheme versions < 4.x:
    	    :mz (require (prefix vim- vimext))
    	else
    	    " newer versions:
    	    :mz (require (prefix-in vim- 'vimext))
    	endif
        endfunction

        if has("mzscheme")
    	silent call MzRequire()
        endif

    ==============================================================================

    3. Threads						*mzscheme-threads*

    The MzScheme interface supports threads. They are independent from OS threads,
    thus scheduling is required. The option 'mzquantum' determines how often
    Vim should poll for available MzScheme threads.
    NOTE
    Thread scheduling in the console version of Vim is less reliable than in the
    GUI version.

    ==============================================================================

    4. Vim access from MzScheme				*mzscheme-vim*

    							*mzscheme-vimext*
    The 'vimext' module provides access to procedures defined in the MzScheme
    interface.

    Common
        (command {command-string})	    Perform the vim ":Ex" style command.
        (eval {expr-string})	    Evaluate the vim expression into
    				    respective MzScheme object: |Lists| are
    				    represented as Scheme lists,
    				    |Dictionaries| as hash tables,
    				    |Funcref|s as functions (see also
    				    |mzscheme-funcref|)
    				    NOTE the name clashes with MzScheme eval,
    				    use module qualifiers to overcome this.
        (range-start)		    Start/End of the range passed with
        (range-end)			    the Scheme command.
        (beep)			    beep
        (get-option {option-name} [buffer-or-window]) Get Vim option value (either
    				    local or global, see set-option).
        (set-option {string} [buffer-or-window])
    				    Set a Vim option. String must have option
    				    setting form (like optname=optval, or
    				    optname+=optval, etc.) When called with
    				    {buffer} or {window} the local option will
    				    be set. The symbol 'global can be passed
    				    as {buffer-or-window}. Then |:setglobal|
    				    will be used.

    Buffers							 *mzscheme-buffer*
        (buff? {object})		    Is object a buffer?
        (buff-valid? {object})	    Is object a valid buffer? (i.e.
    				    corresponds to the real Vim buffer)
        (get-buff-line {linenr} [buffer])
    				    Get line from a buffer.
        (set-buff-line {linenr} {string} [buffer])
    				    Set a line in a buffer. If {string} is #f,
    				    the line gets deleted.  The [buffer]
    				    argument is optional. If omitted, the
    				    current buffer will be used.
        (get-buff-line-list {start} {end} [buffer])
    				    Get a list of lines in a buffer. {Start}
    				    and {end} are 1-based and inclusive.
        (set-buff-line-list {start} {end} {string-list} [buffer])
    				    Set a list of lines in a buffer. If
    				    string-list is #f or null, the lines get
    				    deleted. If a list is shorter than
    				    {end}-{start} the remaining lines will
    				    be deleted.
        (get-buff-name [buffer])	    Get a buffer's text name.
        (get-buff-num [buffer])	    Get a buffer's number.
        (get-buff-size [buffer])	    Get buffer line count.
        (insert-buff-line-list {linenr} {string/string-list} [buffer])
    				    Insert a list of lines into a buffer after
    				    {linenr}. If {linenr} is 0, lines will be
    				    inserted at start.
        (curr-buff)			    Get the current buffer. Use other MzScheme
    				    interface procedures to change it.
        (buff-count)		    Get count of total buffers in the editor.
        (get-next-buff [buffer])	    Get next buffer.
        (get-prev-buff [buffer])	    Get previous buffer. Return #f when there
    				    are no more buffers.
        (open-buff {filename})	    Open a new buffer (for file "name")
        (get-buff-by-name {buffername}) Get a buffer by its filename or #f
    					if there is no such buffer.
        (get-buff-by-num {buffernum})   Get a buffer by its number (return #f if
    				    there is no buffer with this number).

    Windows							    *mzscheme-window*
        (win? {object})		    Is object a window?
        (win-valid? {object})	    Is object a valid window (i.e. corresponds
    				    to the real Vim window)?
        (curr-win)			    Get the current window.
        (win-count)			    Get count of windows.
        (get-win-num [window])	    Get window number.
        (get-win-by-num {windownum})    Get window by its number.
        (get-win-buffer	[window])   Get the buffer for a given window.
        (get-win-height [window])
        (set-win-height {height} [window])  Get/Set height of window.
        (get-win-width [window])
        (set-win-width {width} [window])Get/Set width of window.
        (get-win-list [buffer])	    Get list of windows for a buffer.
        (get-cursor [window])	    Get cursor position in a window as
    				    a pair (linenr . column).
        (set-cursor (line . col) [window])  Set cursor position.

    ==============================================================================

    5. mzeval() Vim function				    *mzscheme-mzeval*

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

    ==============================================================================

    6. Using Function references				    *mzscheme-funcref*

    MzScheme interface allows use of |Funcref|s so you can call Vim functions
    directly from Scheme. For instance:
        function! MyAdd2(arg)
    	return a:arg + 2
        endfunction
        mz (define f2 (vim-eval "function(\"MyAdd2\")"))
        mz (f2 7)
      or :
        :mz (define indent (vim-eval "function('indent')"))
        " return Vim indent for line 12
        :mz (indent 12)

    ==============================================================================

    7. Dynamic loading				*mzscheme-dynamic* *E815*

    On MS-Windows the MzScheme libraries can be loaded dynamically. The |:version|
    output then includes |+mzscheme/dyn|.

    This means that Vim will search for the MzScheme DLL files only when needed.
    When you don't use the MzScheme interface you don't need them, thus you can
    use Vim without these DLL files.
    NOTE: Newer version of MzScheme (Racket) require earlier (trampolined)
    initialisation via scheme_main_setup.  So Vim always loads the MzScheme DLL at
    startup if possible.  This may make Vim startup slower.

    To use the MzScheme interface the MzScheme DLLs must be in your search path.
    In a console window type "path" to see what directories are used.

    On MS-Windows the options 'mzschemedll' and 'mzschemegcdll' are used for the
    name of the library to load.  The initial value is specified at build time.

    The version of the DLL must match the MzScheme version Vim was compiled with.
    For MzScheme version 209 they will be "libmzsch209_000.dll" and
    "libmzgc209_000.dll". To know for sure look at the output of the ":version"
    command, look for -DDYNAMIC_MZSCH_DLL="something" and
    -DDYNAMIC_MZGC_DLL="something" in the "Compilation" info.

    For example, if MzScheme (Racket) is installed at C:\Racket63, you may need
    to set the environment variable as the following:

      PATH=%PATH%;C:\Racket63\lib
      PLTCOLLECTS=C:\Racket63\collects
      PLTCONFIGDIR=C:\Racket63\etc

    ==============================================================================

    8. MzScheme setup				    *mzscheme-setup* *E895*

    Vim requires "racket/base" module for if_mzsch core (fallback to "scheme/base"
    if it doesn't exist), "r5rs" module for test and "raco ctool" command for
    building Vim.  If MzScheme did not have them, you can install them with
    MzScheme's raco command:

      raco pkg install scheme-lib       # scheme/base module
      raco pkg install r5rs-lib         # r5rs module
      raco pkg install cext-lib         # raco ctool command

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