mcedit - Online in the Cloud

PROGRAM:

NAME

mcedit - Internal file editor of GNU Midnight Commander.

USAGE

mcedit [-bcCdfhstVx?] [+lineno] [file1] [file2] ...

mcedit [-bcCdfhstVx?] file1:lineno[:] file2:lineno[:] ...

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 files specified
on the command line. The editor is based on the terminal version of cooledit - standalone
editor for X Window System.

OPTIONS

+lineno
Go to the line specified by number (do not put a space between the + sign and the
number). Several line numbers are allowed but the last one will be actual and it
will be applied to the first file only.

-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>,<attributes>:<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 windowed editor. It can edit several files at
the same time. Maximim size of each file is 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; shift-arrow text highlighting (if supported by the terminal);
insert-overwrite toggle; autoindent; tunable tab size; syntax highlighting for various
file types; and an option to pipe text blocks through shell commands like indent and
ispell.

Each file is opened in its own window in full-screen mode. Window control in mcedit is
similar to the window control in other multi-window program: double click on window title
maximizes the window to full-screen or restores window size and position; left-click on
window title and mouse drag moves the window in editor area; left-click on low-right frame
corner and mouse drag resizes the window. These actions can be made using "Window" menu.

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 ~/.cache/mc/mcedit/mcedit.clip, Shift-Ins
pastes from ~/.cache/mc/mcedit/mcedit.clip, Shift-Del cuts to
~/.cache/mc/mcedit/mcedit.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 Meta-Tab or Escape Tab) completes the word under the cursor
using the words used in the file.

MACRO

To define a macro, press Ctrl-R and then type out the keys you want to be executed. Press
Ctrl-R again when finished. The macro can be assigned to any key by pressing that key.
The macro is executed when you press the assigned key.

The macro commands are stored in section [editor] it the file ~/.local/share/mc/mc.macros.

External scripts (filters) can be assigned into the any hotkey by edit mc.macros like
following:

[editor]
ctrl-W=ExecuteScript:25;

This means that ctrl-W hotkey initiates the ExecuteScript(25) action, then editor handler
translates this into execution of ~/.local/share/mc/mcedit/macros.d/macro.25.sh shell
script.

External scripts are stored in ~/.local/share/mc/mcedit/macros.d/ directory and must be
named as macro.XXXX.sh where XXXX is the number from 0 to 9999. See Edit Menu File for
more detail about format of the script.

Following macro definition and directives can be used:

#silent
If this directive is set, then script starts without interactive subshell.

%c The cursor column position number.

%i The indent of blank space, equal the cursor column.

%y The syntax type of current file.

%b The block file name.

%f The current file name.

%n Only the current file name without extension.

%x The extension of current file name.

%d The current directory name.

%F The current file in the unselected panel.

%D The directory name of the unselected panel.

%t The currently tagged files.

%T The tagged files in the unselected panel.

%u and %U Similar to the %t and %T macros, but in addition the files are untagged. You
can use this macro only once per menu file entry or extension file entry, because
next time there will be no tagged files.

%s and %S The selected files: The tagged files if there are any. Otherwise the current
file.

Feel free to edit this files, if you need. Here is a sample external script:

l comment selection
TMPFILE=`mktemp ${MC_TMPDIR:-/tmp}/up.XXXXXX` || exit 1
echo #if 0 > $TMPFILE
cat %b >> $TMPFILE
echo #endif >> $TMPFILE
cat $TMPFILE > %b
rm -f $TMPFILE

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

CODE NAVIGATION

mcedit can be used to navigation through code with tags files created by etags or ctags
commands. If there is no file TAGS code navigation would not work. In example, in case of
exuberant-ctags for C language command will be:

ctags -e --language-force=C -R ./

Meta-Enter show list box to select item under cursor (cusor should stand at end of word).

Meta-Minus where minus is symbol "-" go to previous function in navigation list (like a
browser Back).

Meta-Equal where equal is symbol "=" go to next function in navigation list (like a
browser Forward).

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 ~/.config/mc/mcedit/Syntax. If this file is
missing, system-wide /usr/share/mc/syntax/Syntax is used. The file
~/.config/mc/mcedit/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] [attributes]

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

context default [foreground] [background] [attributes]

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]
[attributes]

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. The
special keyword "default" means the terminal's default. Another special keyword "base"
means mc's main colors, it is useful as a placeholder if you want to specify attributes
without modifying the background color. When 256 colors are available, they can be
specified either as color16 to color255, or as rgb000 to rgb555 and gray0 to gray23.

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.

Attributes can be any of bold, italic, underline, reverse and blink, appended by a plus
sign if more than one are desired.

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

If you are describing case insensitive language you need to use caseinsensitive directive.
It should be specified at the beginning of syntax file.

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.

The syntax highlighting can be toggled using Ctrl-s shortcut.

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 ~/.config/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_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.

editor_word_wrap_line_length
line length to wrap. 72 default.

editor_backup_extension
symbol for add extension to name of backup files. Default "~".

editor_line_state
show state line of editor now it show number of file line (in future it can show
things like folding, breakpoints, etc.). M-n toglle this option.

editor_visible_spaces
Toggle show visible trailing spaces (TWS), if editor_visible_spaces=1 TWS showed as
'.'

editor_visible_tabs
Toggle show visible tabs, if editor_visible_tabs=1 tabs showed as '<---->'

editor_persistent_selections
Do not remove block selection after moving the cursor.

editor_drop_selection_on_copy
Reset selection after copy to clipboard.

editor_cursor_beyond_eol
Allow moving cursor beyond the end of line.

editor_cursor_after_inserted_block
Allow moving cursor after inserted block.

editor_syntax_highlighting
enable syntax highlighting.

editor_edit_confirm_save
show confirm dialog on save.

editor_option_typewriter_wrap
to be described

editor_option_auto_para_formatting
to be described

editor_option_save_position
save file position on exit.

source_codepage
symbol representation of codepage name for file (i.e. CP1251, ~ - default).

editor_group_undo
do UNDO for several of the same type of action (inserting/overwriting, deleting,
navigating, typing)

editor_wordcompletion_collect_entire_file
Search autocomplete candidates in entire of file or just from begin of file to
cursor position (0)

spell_language
Spelling language (en, en-variant_0, ru, etc) installed with aspell package (a full
list can be get using 'aspell' utility). Use spell_language = NONE to disable
aspell support. Default value is 'en'. Option must located in the [Misc] section.

editor_stop_format_chars
Set of characters to stop paragraph formatting. If one of those characters is found
in the begin of line, that line and all following lines of paragraph will be
untouched. Default value is "-+*\,.;:&>".

editor_state_full_filename
Show full file name in the status line. If disabled, the only file name is shown.

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.

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