neovim-curwin-ffi.lua

local ffi = require("ffi")
ffi.cdef[[

  typedef int handle_T;
  typedef long linenr_T;         // line number type
  typedef int colnr_T;

  typedef struct {
    linenr_T lnum;        /* line number */
    colnr_T col;          /* column number */
    colnr_T coladd;
  } pos_T;

  struct window_S {
    handle_T handle;                  ///< unique identifier for the window

    void       *w_buffer;            ///< buffer we are a window into (used
                                      ///< often, keep it the first item!)

    void  *w_s;                 ///< for :ownsyntax

    int w_hl_id_normal;               ///< 'winhighlight' normal id
    int w_hl_attr_normal;             ///< 'winhighlight' normal final attrs

    int w_hl_ids[51];          ///< 'winhighlight' id
    int w_hl_attrs[51];        ///< 'winhighlight' final attrs

    int w_hl_needs_update;            ///< attrs need to be recalculated

    void       *w_prev;              ///< link to previous window
    void       *w_next;              ///< link to next window
    _Bool w_closing;                   ///< window is being closed, don't let
                                      ///  autocommands close it too.

    void     *w_frame;             ///< frame containing this window

    pos_T w_cursor;                   ///< cursor position in buffer

    colnr_T w_curswant;               ///< Column we want to be at.  This is
                                      ///  used to try to stay in the same column
                                      ///  for up/down cursor motions.

    int w_set_curswant;               // If set, then update w_curswant the next
                                      // time through cursupdate() to the
                                      // current virtual column

    linenr_T w_last_cursorline;       ///< where last 'cursorline' was drawn
    pos_T w_last_cursormoved;         ///< for CursorMoved event

    // the next seven are used to update the visual part
    char w_old_visual_mode;           ///< last known VIsual_mode
    linenr_T w_old_cursor_lnum;       ///< last known end of visual part
    colnr_T w_old_cursor_fcol;        ///< first column for block visual part
    colnr_T w_old_cursor_lcol;        ///< last column for block visual part
    linenr_T w_old_visual_lnum;       ///< last known start of visual part
    colnr_T w_old_visual_col;         ///< last known start of visual part
    colnr_T w_old_curswant;           ///< last known value of Curswant

    // 'listchars' characters. Defaults set in set_chars_option().
    struct {
      int eol;
      int ext;
      int prec;
      int nbsp;
      int space;
      int tab1;                       ///< first tab character
      int tab2;                       ///< second tab character
      int tab3;                       ///< third tab character
      int lead;
      int trail;
      int conceal;
    } w_p_lcs_chars;

    // 'fillchars' characters. Defaults set in set_chars_option().
    struct {
      int stl;
      int stlnc;
      int vert;
      int fold;
      int foldopen;                    ///< when fold is open
      int foldclosed;                  ///< when fold is closed
      int foldsep;                     ///< continuous fold marker
      int diff;
      int msgsep;
      int eob;
    } w_p_fcs_chars;

    /*
    * "w_topline", "w_leftcol" and "w_skipcol" specify the offsets for
    * displaying the buffer.
    */
    linenr_T w_topline;               /* buffer line number of the line at the
                                        top of the window */
    char w_topline_was_set;           /* flag set to TRUE when topline is set,
                                        e.g. by winrestview() */
    int w_topfill;                    // number of filler lines above w_topline
    int w_old_topfill;                // w_topfill at last redraw
    _Bool w_botfill;                   // true when filler lines are actually
                                      // below w_topline (at end of file)
    _Bool w_old_botfill;               // w_botfill at last redraw
    colnr_T w_leftcol;                // window column number of the left most
                                      // character in the window; used when
                                      // 'wrap' is off
    colnr_T w_skipcol;                // starting column when a single line
                                      // doesn't fit in the window
    // NOTE: CROPPED FOR BREVITY
  };

  typedef struct window_S win_T;

  extern win_T    *curwin;
]]

print(ffi.C.curwin.w_leftcol)