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MCEDIT

Section: GNU Midnight Commander (1)
Updated: January 2003
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NAME

mcedit - Internal file editor of GNU Midnight Commander.  

USAGE

mcedit [-bcCdfhstVx?] [+number] file  

DESCRIPTION

mcedit is a link to mc, the main GNU Midnight Commander executable. Executing GNU Midnight Commander under this name requests staring the internal editor and opening the file specified on the command line. The editor is based on the terminal version of cooledit - standalone editor for X Window System.  

OPTIONS

+number
Go to the line specified by number (do not put a space between the + sign and the number).
-b
Force black and white display.
-c
Force ANSI color mode on terminals that don't seem to have color support.
-C <keyword>=<FGcolor>,<BGcolor>:<keyword>= ...
Specify a different color set. See the Colors section in mc(1) for more information.
-d
Disable mouse support.
-f
Display the compiled-in search path for GNU Midnight Commander data files.
-t
Force using termcap database instead of terminfo. This option is only applicable if GNU Midnight Commander was compiled with S-Lang library with terminfo support.
-V
Display the version of the program.
-x
Force xterm mode. Used when running on xterm-capable terminals (two screen modes, and able to send mouse escape sequences).
 

FEATURES

The internal file editor is a full-featured full screen editor. It can edit files up to 64 megabytes. It is possible to edit binary files. The features it presently supports are: block copy, move, delete, cut, paste; key for key undo; pull-down menus; file insertion; macro commands; regular expression search and replace (and our own scanf-printf search and replace); shift-arrow text highlighting (if supported by the terminal); insert-overwrite toggle; word wrap; autoindent; tunable tab size; syntax highlighting for various file types; and an option to pipe text blocks through shell commands like indent and ispell.  

KEYS

The editor is easy to use and can be used without learning. The pull-down menu is invoked by pressing F9. You can learn other keys from the menu and from the button bar labels.

In addition to that, Shift combined with arrows does text highlighting (if supported by the terminal): Ctrl-Ins copies to the file ~/.mc/cedit/cooledit.clip, Shift-Ins pastes from ~/.mc/cedit/cooledit.clip, Shift-Del cuts to ~/.mc/cedit/cooledit.clip, and Ctrl-Del deletes highlighted text. Mouse highlighting also works on some terminals. To use the standard mouse support provided by your terminal, hold the Shift key. Please note that the mouse support in the terminal doesn't share the clipboard with mcedit.

The completion key (usually Alt-Tab or Escape Tab) completes the word under the cursor using the words used earlier in the file.

To define a macro, press Ctrl-R and then type out the keys you want to be executed. Press Ctrl-R again when finished. You can then assign the macro to any key you like by pressing that key. The macro is executed when you press Ctrl-A and then the assigned key. The macro is also executed if you press Meta, Ctrl, or Esc and the assigned key, provided that the key is not used for any other function. The macro commands are stored in the file ~/.mc/cedit/cooledit.macros. Do NOT edit this file if you are going to use macros again in the same editing session, because mcedit caches macro key defines in memory. mcedit now overwrites a macro if a macro with the same key already exists, so you won't have to edit this file. You will also have to restart other running editors for macros to take effect. F19 will format C, C++, Java or HTML code when it is highlighted. An executable file called ~/.mc/cedit/edit.indent.rc will be created for you from the default template. Feel free to edit it if you need.

C-p will run ispell on a block of text in a similar way. The script file will be called ~/.mc/cedit/edit.spell.rc.

If some keys don't work, you can use Learn Keys in the Options menu.  

SYNTAX HIGHLIGHTING

mcedit supports syntax highlighting. This means that keywords and contexts (like C comments, string constants, etc) are highlighted in different colors. The following section explains the format of the file ~/.mc/cedit/Syntax. If this file is missing, system-wide /usr/share/mc/syntax/Syntax is used. The file ~/.mc/cedit/Syntax is rescanned on opening of a any new editor file. The file contains rules for highlighting, each of which is given on a separate line, and define which keywords will be highlighted to what color.

The file is divided into sections, each beginning with a line with the file command. The sections are normally put into separate files using the include command.

The file command has three arguments. The first argument is a regular expression that is applied to the file name to determine if the following section applies to the file. The second argument is the description of the file type. It is used in cooledit; future versions of mcedit may use it as well. The third optional argument is a regular expression to match the first line of text of the file. The rules in the following section apply if either the file name or the first line of text matches.

A section ends with the start of another section. Each section is divided into contexts, and each context contains rules. A context is a scope within the text that a particular set of rules belongs to. For instance, the text within a C style comment (i.e. between /* and */) has its own color. This is a context, although it has no further rules inside it because there is probably nothing that we want highlighted within a C comment.

A trivial C programming section might look like this:

file .\*\\.c C\sProgram\sFile (#include|/\\\*)

wholechars abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ_

# default colors
define  comment   brown
context default
  keyword  whole  if       yellow
  keyword  whole  else     yellow
  keyword  whole  for      yellow
  keyword  whole  while    yellow
  keyword  whole  do       yellow
  keyword  whole  switch   yellow
  keyword  whole  case     yellow
  keyword  whole  static   yellow
  keyword  whole  extern   yellow
  keyword         {        brightcyan
  keyword         }        brightcyan
  keyword         '*'      green

# C comments
context /\* \*/ comment

# C preprocessor directives
context linestart # \n red
  keyword  \\\n  brightred

# C string constants
context " " green
  keyword  %d    brightgreen
  keyword  %s    brightgreen
  keyword  %c    brightgreen
  keyword  \\"   brightgreen

Each context starts with a line of the form:

context [exclusive] [whole|wholeright|wholeleft] [linestart] delim [linestart] delim [foreground] [background]

The first context is an exception. It must start with the command

context default [foreground] [background]

otherwise mcedit will report an error. The linestart option specifies that delim must start at the beginning of a line. The whole option tells that delim must be a whole word. To specify that a word must begin on the word boundary only on the left side, you can use the wholeleft option, and similarly a word that must end on the word boundary is specified by wholeright.

The set of characters that constitute a whole word can be changed at any point in the file with the wholechars command. The left and right set of characters can be set separately with

wholechars [left|right] characters

The exclusive option causes the text between the delimiters to be highlighted, but not the delimiters themselves.

Each rule is a line of the form:

keyword [whole|wholeright|wholeleft] [linestart] string foreground [background]

Context or keyword strings are interpreted, so that you can include tabs and spaces with the sequences \t and \s. Newlines and backslashes are specified with \n and \\ respectively. Since whitespace is used as a separator, it may not be used as is. Also, \* must be used to specify an asterisk. The * itself is a wildcard that matches any length of characters. For example,

  keyword         '*'      green

colors all C single character constants green. You also could use

  keyword         "*"      green

to color string constants, but the matched string would not be allowed to span across multiple newlines. The wildcard may be used within context delimiters as well, but you cannot have a wildcard as the last or first character.

Important to note is the line

  keyword  \\\n  brightgreen

This line defines a keyword containing the backslash and newline characters. Since the keywords are matched before the context delimiters, this keyword prevents the context from ending at the end of the lines that end in a backslash, thus allowing C preprocessor directive to continue across multiple lines.

The possible colors are: black, gray, red, brightred, green, brightgreen, brown, yellow, blue, brightblue, magenta, brightmagenta, cyan, brightcyan, lightgray and white. If the syntax file is shared with cooledit, it is possible to specify different colors for mcedit and cooledit by separating them with a slash, e.g.

keyword  #include  red/Orange

mcedit uses the color before the slash. See cooledit(1) for supported cooledit colors.

Comments may be put on a separate line starting with the hash sign (#).

Because of the simplicity of the implementation, there are a few intricacies that will not be dealt with correctly but these are a minor irritation. On the whole, a broad spectrum of quite complicated situations are handled with these simple rules. It is a good idea to take a look at the syntax file to see some of the nifty tricks you can do with a little imagination. If you cannot get by with the rules I have coded, and you think you have a rule that would be useful, please email me with your request. However, do not ask for regular expression support, because this is flatly impossible.

A useful hint is to work with as much as possible with the things you can do rather than try to do things that this implementation cannot deal with. Also remember that the aim of syntax highlighting is to make programming less prone to error, not to make code look pretty.  

COLORS

The default colors may be changed by appending to the MC_COLOR_TABLE environment variable. Foreground and background colors pairs may be specified for example with:

MC_COLOR_TABLE="$MC_COLOR_TABLE:\
editnormal=lightgray,black:\
editbold=yellow,black:\
editmarked=black,cyan"
 

OPTIONS

Most options can now be set from the editors options dialog box. See the Options menu. The following options are defined in ~/.mc/ini and have obvious counterparts in the dialog box. You can modify them to change the editor behavior, by editing the file. Unless specified, a 1 sets the option to on, and a 0 sets it to off, as is usual.
use_internal_edit
This option is ignored when invoking mcedit.
editor_key_emulation
1 for Emacs keys, and 0 for normal Cooledit keys.
editor_tab_spacing
Interpret the tab character as being of this length. Default is 8. You should avoid using other than 8 since most other editors and text viewers assume a tab spacing of 8. Use editor_fake_half_tabs to simulate a smaller tab spacing.
editor_fill_tabs_with_spaces
Never insert a tab space. Rather insert spaces (ascii 20h) to fill to the desired tab size.
editor_return_does_auto_indent
Pressing return will tab across to match the indentation of the first line above that has text on it.
editor_backspace_through_tabs
Make a single backspace delete all the space to the left margin if there is no text between the cursor and the left margin.
editor_fake_half_tabs
This will emulate a half tab for those who want to program with a tab spacing of 4, but do not want the tab size changed from 8 (so that the code will be formatted the same when displayed by other programs). When editing between text and the left margin, moving and tabbing will be as though a tab space were 4, while actually using spaces and normal tabs for an optimal fill. When editing anywhere else, a normal tab is inserted.
editor_option_save_mode
Possible values 0, 1 and 2. The save mode (see the options menu also) allows you to change the method of saving a file. Quick save (0) saves the file by immediately, truncating the disk file to zero length (i.e. erasing it) and the writing the editor contents to the file. This method is fast, but dangerous, since a system error during a file save will leave the file only partially written, possibly rendering the data irretrievable. When saving, the safe save (1) option enables creation of a temporary file into which the file contents are first written. In the event of an problem, the original file is untouched. When the temporary file is successfully written, it is renamed to the name of the original file, thus replacing it. The safest method is create backups (2). Where a backup file is created before any changes are made. You can specify your own backup file extension in the dialog. Note that saving twice will replace your backup as well as your original file.
 

MISCELLANEOUS

You can use scanf search and replace to search and replace a C format string. First take a look at the sscanf and sprintf man pages to see what a format string is and how it works. Here's an example: suppose that you want to replace all occurrences of an open bracket, three comma separated numbers, and a close bracket, with the word apples, the third number, the word oranges and then the second number. You would fill in the Replace dialog box as follows:

Enter search string
(%d,%d,%d)
Enter replace string
apples %d oranges %d
Enter replacement argument order
3,2

The last line specifies that the third and then the second number are to be used in place of the first and second.

It is advisable to use this feature with Prompt On Replace on, because a match is thought to be found whenever the number of arguments found matches the number given, which is not always a real match. Scanf also treats whitespace as being elastic. Note that the scanf format %[ is very useful for scanning strings, and whitespace.

The editor also displays non-us characters (160+). When editing binary files, you should set display bits to 7 bits in the Midnight Commander options menu to keep the spacing clean.  

FILES

/usr/share/mc/mc.hlp
The help file for the program.

/usr/share/mc/mc.ini

The default system-wide setup for GNU Midnight Commander, used only if the user's own ~/.mc/ini file is missing.

/usr/share/mc/mc.lib

Global settings for the Midnight Commander. Settings in this file affect all users, whether they have ~/.mc/ini or not.

/usr/share/mc/syntax/*

The default system-wide syntax files for mcedit, used only if the corresponding user's own ~/.mc/cedit/ file is missing.

$HOME/.mc/ini

User's own setup. If this file is present then the setup is loaded from here instead of the system-wide setup file.

$HOME/.mc/cedit/

User's own directory where block commands are processed and saved and user's own syntax files are located.
 

LICENSE

This program is distributed under the terms of the GNU General Public License as published by the Free Software Foundation. See the built-in help of the Midnight Commander for details on the License and the lack of warranty.  

AVAILABILITY

The latest version of this program can be found at ftp://ftp.ibiblio.org/pub/Linux/utils/file/managers/mc/.  

SEE ALSO

cooledit(1), mc(1), gpm(1), terminfo(1), scanf(3).  

AUTHORS

Paul Sheer (psheer@obsidian.co.za) is the original author of the Midnight Commander's internal editor.  

BUGS

Bugs should be reported to mc-devel@gnome.org


 

Index

NAME
USAGE
DESCRIPTION
OPTIONS
FEATURES
KEYS
SYNTAX HIGHLIGHTING
COLORS
OPTIONS
MISCELLANEOUS
FILES
LICENSE
AVAILABILITY
SEE ALSO
AUTHORS
BUGS




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