1README for the Vim source code 2 3Here are a few hints for finding your way around the source code. This 4doesn't make it less complex than it is, but it gets you started. 5 6You might also want to read ":help development". 7 8 9JUMPING AROUND 10 11First of all, use ":make tags" to generate a tags file, so that you can use 12the ":tag" command to jump around the source code. 13 14To jump to a function or variable definition, move the cursor on the name and 15use the CTRL-] command. Use CTRL-T or CTRL-O to jump back. 16 17To jump to a file, move the cursor on its name and use the "gf" command. 18 19Most code can be found in a file with an obvious name (incomplete list): 20 buffer.c manipulating buffers (loaded files) 21 diff.c diff mode (vimdiff) 22 eval.c expression evaluation 23 fileio.c reading and writing files 24 fold.c folding 25 getchar.c getting characters and key mapping 26 mark.c marks 27 mbyte.c multi-byte character handling 28 memfile.c storing lines for buffers in a swapfile 29 memline.c storing lines for buffers in memory 30 menu.c menus 31 message.c (error) messages 32 ops.c handling operators ("d", "y", "p") 33 option.c options 34 quickfix.c quickfix commands (":make", ":cn") 35 regexp.c pattern matching 36 screen.c updating the windows 37 search.c pattern searching 38 spell.c spell checking 39 syntax.c syntax and other highlighting 40 tag.c tags 41 term.c terminal handling, termcap codes 42 undo.c undo and redo 43 window.c handling split windows 44 45 46IMPORTANT VARIABLES 47 48The current mode is stored in "State". The values it can have are NORMAL, 49INSERT, CMDLINE, and a few others. 50 51The current window is "curwin". The current buffer is "curbuf". These point 52to structures with the cursor position in the window, option values, the file 53name, etc. These are defined in structs.h. 54 55All the global variables are declared in globals.h. 56 57 58THE MAIN LOOP 59 60This is conveniently called main_loop(). It updates a few things and then 61calls normal_cmd() to process a command. This returns when the command is 62finished. 63 64The basic idea is that Vim waits for the user to type a character and 65processes it until another character is needed. Thus there are several places 66where Vim waits for a character to be typed. The vgetc() function is used for 67this. It also handles mapping. 68 69Updating the screen is mostly postponed until a command or a sequence of 70commands has finished. The work is done by update_screen(), which calls 71win_update() for every window, which calls win_line() for every line. 72See the start of screen.c for more explanations. 73 74 75COMMAND-LINE MODE 76 77When typing a ":", normal_cmd() will call getcmdline() to obtain a line with 78an Ex command. getcmdline() contains a loop that will handle each typed 79character. It returns when hitting <CR> or <Esc> or some other character that 80ends the command line mode. 81 82 83EX COMMANDS 84 85Ex commands are handled by the function do_cmdline(). It does the generic 86parsing of the ":" command line and calls do_one_cmd() for each separate 87command. It also takes care of while loops. 88 89do_one_cmd() parses the range and generic arguments and puts them in the 90exarg_t and passes it to the function that handles the command. 91 92The ":" commands are listed in ex_cmds.h. The third entry of each item is the 93name of the function that handles the command. The last entry are the flags 94that are used for the command. 95 96 97NORMAL MODE COMMANDS 98 99The Normal mode commands are handled by the normal_cmd() function. It also 100handles the optional count and an extra character for some commands. These 101are passed in a cmdarg_t to the function that handles the command. 102 103There is a table nv_cmds in normal.c which lists the first character of every 104command. The second entry of each item is the name of the function that 105handles the command. 106 107 108INSERT MODE COMMANDS 109 110When doing an "i" or "a" command, normal_cmd() will call the edit() function. 111It contains a loop that waits for the next character and handles it. It 112returns when leaving Insert mode. 113 114 115OPTIONS 116 117There is a list with all option names in option.c, called options[]. 118 119 120THE GUI 121 122Most of the GUI code is implemented like it was a clever terminal. Typing a 123character, moving a scrollbar, clicking the mouse, etc. are all translated 124into events which are written in the input buffer. These are read by the 125main code, just like reading from a terminal. The code for this is scattered 126through gui.c. For example: gui_send_mouse_event() for a mouse click and 127gui_menu_cb() for a menu action. Key hits are handled by the system-specific 128GUI code, which calls add_to_input_buf() to send the key code. 129 130Updating the GUI window is done by writing codes in the output buffer, just 131like writing to a terminal. When the buffer gets full or is flushed, 132gui_write() will parse the codes and draw the appropriate items. Finally the 133system-specific GUI code will be called to do the work. 134 135 136DEBUGGING THE GUI 137 138Remember to prevent that gvim forks and the debugger thinks Vim has exited, 139add the "-f" argument. In gdb: "run -f -g". 140 141When stepping through display updating code, the focus event is triggered 142when going from the debugger to Vim and back. To avoid this, recompile with 143some code in gui_focus_change() disabled. 144