From 8ac8a77f24098b58316bbfdf2f6c2c3f7f2b35c2 Mon Sep 17 00:00:00 2001 From: Bram Moolenaar Date: Fri, 29 Mar 2019 13:10:08 +0100 Subject: patch 8.1.1069: source README file doesn't look nice on github Problem: Source README file doesn't look nice on github. Solution: Turn it into markdown, still readable as plain text. (WenxuanHuang, closes #4141) --- src/README.md | 190 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 190 insertions(+) create mode 100644 src/README.md (limited to 'src/README.md') diff --git a/src/README.md b/src/README.md new file mode 100644 index 0000000000..53cae38dd8 --- /dev/null +++ b/src/README.md @@ -0,0 +1,190 @@ +![Vim Logo](https://github.com/vim/vim/blob/master/runtime/vimlogo.gif) + +# 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`](http://vimdoc.sourceforge.net/htmldoc/develop.html#development). + + +## Jumping around ## + +First of all, use `:make tags` to generate a tags file, so that you can jump +around in 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): + +File name | Description +--------- | ----------- +autocmd.c | autocommands +buffer.c | manipulating buffers (loaded files) +diff.c | diff mode (vimdiff) +eval.c | expression evaluation +fileio.c | reading and writing files +findfile.c | search for files in 'path' +fold.c | folding +getchar.c | getting characters and key mapping +indent.c | C and Lisp indentation +mark.c | marks +mbyte.c | multi-byte character handling +memfile.c | storing lines for buffers in a swapfile +memline.c | storing lines for buffers in memory +menu.c | menus +message.c | (error) messages +ops.c | handling operators ("d", "y", "p") +option.c | options +quickfix.c | quickfix commands (":make", ":cn") +regexp.c | pattern matching +screen.c | updating the windows +search.c | pattern searching +sign.c | signs +spell.c | spell checking +syntax.c | syntax and other highlighting +tag.c | tags +term.c | terminal handling, termcap codes +undo.c | undo and redo +window.c | handling split windows + + +## Debugging ## + +If you have a reasonable recent version of gdb, you can use the `:Termdebug` +command to debug Vim. See `:help :Termdebug`. + +When something is time critical or stepping through code is a hassle, use the +channel logging to create a time-stamped log file. Add lines to the code like +this: + + ch_log(NULL, "Value is now %02x", value); + +After compiling and starting Vim, do: + + :call ch_logfile('debuglog', 'w') + +And edit `debuglog` to see what happens. The channel functions already have +`ch_log()` calls, thus you always see that in the log. + + +## 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`](https://github.com/vim/vim/blob/master/src/globals.h). + +All the global variables are declared in +[`globals.h`](https://github.com/vim/vim/blob/master/src/structs.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`](https://github.com/vim/vim/blob/master/src/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`](https://github.com/vim/vim/blob/master/src/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`](https://github.com/vim/vim/blob/master/src/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`](https://github.com/vim/vim/blob/master/src/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. + + +## Debugging the GUI ## + +Remember to prevent that gvim forks and the debugger thinks Vim has exited, +add the `-f` argument. In gdb: `run -f -g`. + +When stepping through display updating code, the focus event is triggered +when going from the debugger to Vim and back. To avoid this, recompile with +some code in `gui_focus_change()` disabled. + + +## Contributing ## + +If you would like to help making Vim better, see the +[`CONTRIBUTING.md`](https://github.com/vim/vim/blob/master/CONTRIBUTING.md) +file. + + +This is `README.md` for version 8.1 of the Vim source code. -- cgit v1.2.3