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- README for the Vim source code
-
- Here are a few hints for finding your way around the source code. This
- doesn't make it less complex than it is, but it gets you started.
-
- You might also want to read ":help development".
-
-
- JUMPING AROUND
-
- First of all, use ":make tags" to generate a tags file, so that you can use
- the ":tag" command to jump around the source code.
-
- To jump to a function or variable definition, move the cursor on the name and
- use the CTRL-] command. Use CTRL-T or CTRL-O to jump back.
-
- To jump to a file, move the cursor on its name and use the "gf" command.
-
- Most code can be found in a file with an obvious name (incomplete list):
- buffer.c manipulating buffers (loaded files)
- diff.c diff mode (vimdiff)
- eval.c expression evaluation
- fileio.c reading and writing files
- fold.c folding
- getchar.c getting characters and key mapping
- mark.c marks
- memfile.c storing lines for buffers in a swapfile
- memline.c storing lines for buffers in memory
- menu.c menus
- message.c (error) messages
- mbyte.c multy-byte character handling
- ops.c handling operators ("d", "y", "p")
- option.c options
- quickfix.c quickfix commands (":make", ":cn")
- screen.c updating the windows
- search.c pattern searching
- tag.c tags
- term.c terminal handling, termcap codes
- undo.c undo and redo
- window.c handling split windows
-
-
- IMPORTANT VARIABLES
-
- The current mode is stored in "State". The values it can have are NORMAL,
- INSERT, CMDLINE, and a few others.
-
- The current window is "curwin". The current buffer is "curbuf". These point
- to structures with the cursor position in the window, option values, the file
- name, etc. These are defined in structs.h.
-
- All the global variables are declared in globals.h.
-
-
- THE MAIN LOOP
-
- This is conveniently called main_loop(). It updates a few things and then
- calls normal_cmd() to process a command. This returns when the command is
- finished.
-
- The basic idea is that Vim waits for the user to type a character and
- processes it until another character is needed. Thus there are several places
- where Vim waits for a character to be typed. The vgetc() function is used for
- this. It also handles mapping.
-
- Updating the screen is mostly postponed until a command or a sequence of
- commands has finished. The work is done by update_screen(), which calls
- win_update() for every window, which calls win_line() for every line.
- See the start of screen.c for more explanations.
-
-
- COMMAND-LINE MODE
-
- When typing a ":", normal_cmd() will call getcmdline() to obtain a line with
- an Ex command. getcmdline() contains a loop that will handle each typed
- character. It returns when hitting <CR> or <Esc> or some other character that
- ends the command line mode.
-
-
- EX COMMANDS
-
- Ex commands are handled by the function do_cmdline(). It does the generic
- parsing of the ":" command line and calls do_one_cmd() for each separate
- command. It also takes care of while loops.
-
- do_one_cmd() parses the range and generic arguments and puts them in the
- exarg_t and passes it to the function that handles the command.
-
- The ":" commands are listed in ex_cmds.h. The third entry of each item is the
- name of the function that handles the command. The last entry are the flags
- that are used for the command.
-
-
- NORMAL MODE COMMANDS
-
- The Normal mode commands are handled by the normal_cmd() function. It also
- handles the optional count and an extra character for some commands. These
- are passed in a cmdarg_t to the function that handles the command.
-
- There is a table nv_cmds in normal.c which lists the first character of every
- command. The second entry of each item is the name of the function that
- handles the command.
-
-
- INSERT MODE COMMANDS
-
- When doing an "i" or "a" command, normal_cmd() will call the edit() function.
- It contains a loop that waits for the next character and handles it. It
- returns when leaving Insert mode.
-
-
- OPTIONS
-
- There is a list with all option names in option.c, called options[].
-
-
- THE GUI
-
- Most of the GUI code is implemented like it was a clever terminal. Typing a
- character, moving a scrollbar, clicking the mouse, etc. are all translated
- into events which are written in the input buffer. These are read by the
- main code, just like reading from a terminal. The code for this is scattered
- through gui.c. For example: gui_send_mouse_event() for a mouse click and
- gui_menu_cb() for a menu action. Key hits are handled by the system-specific
- GUI code, which calls add_to_input_buf() to send the key code.
-
- Updating the GUI window is done by writing codes in the output buffer, just
- like writing to a terminal. When the buffer gets full or is flushed,
- gui_write() will parse the codes and draw the appropriate items. Finally the
- system-specific GUI code will be called to do the work.
-