nedit.html

nedit 是一款linux下的开发源码的功能强大的编辑器

disturbed (the usual interpretation of a rectangular selection), but text to
the right of the selection is included in the operation and is pulled in to
the selected region.  This method enables you to fill text to an arbitrary
right margin, without going back and forth to the wrap-margin dialog, as well
as to exclude text to the left of the selection such as comment bars or other
text columns.
<P><HR>
</P><P>
<A NAME="File_Format"></A>
<H2> File Format </H2>
</P><P>
While plain-text is probably the simplest and most interchangeable file
format in the computer world, there is still variation in what plain-text
means from system to system.  Plain-text files can differ in character set,
line termination, and wrapping.
</P><P>
While character set differences are the most obvious and pose the most
challenge to portability, they affect NEdit only indirectly via the same font
and localization mechanisms common to all X applications.  If your system is
set up properly, you will probably never see character-set related problems
in NEdit.  NEdit can not display Unicode text files, or any multi-byte
character set.
</P><P>
The primary difference between an MS DOS format file and a Unix format file,
is how the lines are terminated.  Unix uses a single newline character.  MS
DOS uses a carriage-return and a newline.  NEdit can read and write both file
formats, but internally, it uses the single character Unix standard.  NEdit
auto-detects MS DOS format files based on the line termination at the start
of the file.  Files are judged to be DOS format if all of the first five line
terminators, within a maximum range, are DOS-style.  To change the format in
which NEdit writes a file from DOS to Unix or visa versa, use the Save As...
command and check or un-check the MS DOS Format button.
</P><P>
Wrapping within text files can vary among individual users, as well as from
system to system.  Both Windows and MacOS make frequent use of plain text
files with no implicit right margin.  In these files, wrapping is determined
by the tool which displays them.  Files of this style also exist on Unix
systems, despite the fact that they are not supported by all Unix utilities. 
To display this kind of file properly in NEdit, you have to select the wrap
style called Continuous.  Wrapping modes are discussed in the sections:
Customizing -&#62; Preferences, and Basic Operation -&#62; Shifting and Filling.
</P><P>
The last and most minute of format differences is the terminating newline. 
Some Unix compilers and utilities require a final terminating newline on all
files they read and fail in various ways on files which do not have it.  Vi
and approximately half of Unix editors enforce the terminating newline on all
files that they write; Emacs does not enforce this rule.  Users are divided
on which is best.  NEdit makes the final terminating newline optional
(Preferences -&#62; Default Settings -&#62; Terminate with Line Break on Save).
<P><HR>
</P><P>
<A NAME="Features_for_Programming"></A>
<H1> Features for Programming </H1>
</P><P>
<A NAME="Programming_with_NEdit"></A>
<H2> Programming with NEdit </H2>
</P><P>
Though general in appearance, NEdit has many features intended specifically
for programmers.  Major programming-related topics are listed in separate
sections under the heading: "Features for Programming": <A HREF="#Syntax_Highlighting">Syntax Highlighting</A>,
<A HREF="#Tabs/Emulated_Tabs">Tabs/Emulated Tabs</A>, <A HREF="#Finding_Declarations_(ctags)">Finding Declarations (ctags)</A>, <A HREF="#Calltips">Calltips</A>, and 
<A HREF="#Auto/Smart_Indent">Auto/Smart Indent</A>.  Minor topics related to programming are discussed below:
</P><P>
<H3>Language Modes</H3>
</P><P>
When NEdit initially reads a file, it attempts to determine whether the file
is in one of the computer languages that it knows about.  Knowing what language
a file is written in allows NEdit to assign highlight patterns and smart indent
macros, and to set language specific preferences like word delimiters, tab
emulation, and auto-indent.  Language mode can be recognized from both the file
name and from the first 200 characters of content.  Language mode recognition
and language-specific preferences are configured in: Preferences -&#62; Default
Settings -&#62; Language Modes....
</P><P>
You can set the language mode manually for a window, by selecting it from the
menu: Preferences -&#62; Language Modes.
</P><P>
<H3>Backlighting [EXPERIMENTAL]</H3>
</P><P>
NEdit can be made to set the background color of particular classes of
characters to allow easy identification of those characters. This is
particularly useful if you need to be able to distiguish between tabs
and spaces in a file where the difference is important. The colors used
for backlighting are specified by a resource, "nedit*backlightCharTypes". 
You can turn backlighting on and off through the
Preferences -&#62; Apply Backlighting menu entry.
</P><P>
If you prefer to have backlighting turned on for all new windows, use
the Preferences -&#62; Default Settings -&#62; Apply Backlighting menu entry. 
This settings can be saved along with other preferences using 
Preferences -&#62; Save Defaults.
</P><P>
<B>Important:</B> In future versions of NEdit, the backlighting feature will be
extended and reworked such that it becomes easier to configure. The current
way of controlling it through a resource is generally considered to be below
NEdit's usability standards. These future changes are likely to be
incompatible with the current format of the "nedit*backlightCharTypes"
resource, though. Therefore, it is expected that there will be no automatic
migration path for users who customize the resource.
</P><P>
<H3>Line Numbers</H3>
</P><P>
To find a particular line in a source file by line number, choose Goto Line
#... from the Search menu.  You can also directly select the line number text
in the compiler message in the terminal emulator window (xterm, decterm,
winterm, etc.) where you ran the compiler, and choose Goto Selected from the
Search menu.
</P><P>
To find out the line number of a particular line in your file, turn on
Statistics Line in the Preferences menu and position the insertion point
anywhere on the line.  The statistics line continuously updates the line number
of the line containing the cursor.
</P><P>
To go to a specific column on a given line, choose Goto Line #... from the
Search menu and enter a line number and a column number separated by a 
comma.  (e.g. Enter "100,12" for line 100 column 12.)  If you want to go to
a column on the current line just leave out the line number.  (e.g. Enter
",45" to go the column 45 on the current line.)
</P><P>
<H3>Matching Parentheses</H3>
</P><P>
To help you inspect nested parentheses, brackets, braces, quotes, and other
characters, NEdit has both an automatic parenthesis matching mode, and a Goto
Matching command.  Automatic parenthesis matching is activated when you type,
or move the insertion cursor after a parenthesis, bracket, or brace.  It
momentarily highlights either the opposite character ('Delimiter') or the
entire expression ('Range') when the opposite character is visible in the
window. To find a matching character anywhere in the file, select it or
position the cursor after it, and choose Goto Matching from the Search menu. 
If the character matches itself, such as a quote or slash, select the first
character of the pair.  NEdit will match {, (, [, &#60;, ", ', `, /, and \.
Holding the Shift key while typing the accelerator key (Shift+Ctrl+M, by
default), will select all of the text between the matching characters.
</P><P>
When syntax highlighting is enabled, the matching routines can optionally
make use of the syntax information for improved accuracy. In that case,
a brace inside a highlighted string will not match a brace inside a comment,
for instance.
</P><P>
<H3>Opening Included Files</H3>
</P><P>
The Open Selected command in the File menu understands the C preprocessor's
#include syntax, so selecting an #include line and invoking Open Selected will
generally find the file referred to, unless doing so depends on the settings of
compiler switches or other information not available to NEdit.
</P><P>
<H3>Interface to Programming Tools</H3>
</P><P>
Integrated software development environments such as SGI's CaseVision and
Centerline Software's Code Center, can be interfaced directly with NEdit via
the client server interface.  These tools allow you to click directly on
compiler and runtime error messages and request NEdit to open files, and select
lines of interest.  The easiest method is usually to use the tool's interface
for character-based editors like vi, to invoke nc, but programmatic interfaces
can also be derived using the source code for nc.
</P><P>
There are also some simple compile/review, grep, ctree, and ctags browsers
available in the NEdit contrib directory on ftp.nedit.org.
<P><HR>
</P><P>
<A NAME="Tabs/Emulated_Tabs"></A>
<H2> Tabs/Emulated Tabs </H2>
</P><P>
<H3>Changing the Tab Distance</H3>
</P><P>
Tabs are important for programming in languages which use indentation to show
nesting, as short-hand for producing white-space for leading indents.  As a
programmer, you have to decide how to use indentation, and how or whether tab
characters map to your indentation scheme.
</P><P>
Ideally, tab characters map directly to the amount of indent that you use to
distinguish nesting levels in your code.  Unfortunately, the Unix standard
for interpretation of tab characters is eight characters (probably dating
back to mechanical capabilities of the original teletype), which is usually
too coarse for a single indent.
</P><P>
Most text editors, NEdit included, allow you to change the interpretation of
the tab character, and many programmers take advantage of this, and set their
tabs to 3 or 4 characters to match their programming style.  In NEdit you set
the hardware tab distance in Preferences -&#62; Tabs... for the current window,
or Preferences -&#62; Default Settings -&#62; Tabs... (general), or Preferences -&#62;
Default Settings -&#62; Language Modes... (language-specific) to change the
defaults for future windows.
</P><P>
Changing the meaning of the tab character makes programming much easier while
you're in the editor, but can cause you headaches outside of the editor,
because there is no way to pass along the tab setting as part of a plain-text
file.  All of the other tools which display, print, and otherwise process
your source code have to be made aware of how the tabs are set, and must be
able to handle the change.  Non-standard tabs can also confuse other
programmers, or make editing your code difficult for them if their text
editors don't support changes in tab distance.
</P><P>
<H3>Emulated Tabs</H3>
</P><P>
An alternative to changing the interpretation of the tab character is tab
emulation.  In the Tabs... dialog(s), turning on Emulated Tabs causes the Tab
key to insert the correct number of spaces and/or tabs to bring the cursor
the next emulated tab stop, as if tabs were set at the emulated tab distance
rather than the hardware tab distance. Backspacing immediately after entering
an emulated tab will delete the fictitious tab as a unit, but as soon as you
move the cursor away from the spot, NEdit will forget that the collection of
spaces and tabs is a tab, and will treat it as separate characters.  To enter
a real tab character with "Emulate Tabs" turned on, use Ctrl+Tab.
</P><P>
It is also possible to tell NEdit not to insert ANY tab characters at all in
the course of processing emulated tabs, and in shifting and rectangular
insertion/deletion operations, for programmers who worry about the
misinterpretation of tab characters on other systems.
<P><HR>
</P><P>
<A NAME="Auto/Smart_Indent"></A>
<H2> Auto/Smart Indent </H2>
</P><P>
Programmers who use structured languages usually require some form of
automatic indent, so that they don't have to continually re-type the
sequences of tabs and/or spaces needed to maintain lengthy running indents. 
NEdit therefore offers "smart" indent, in addition to the traditional
automatic indent which simply lines up the cursor position with the previous
line.
</P><P>
<H3>Smart Indent</H3>
</P><P>
Smart indent macros are only available by default for C and C++, and while
these can easily be configured for different default indentation distances,
they may not conform to everyone's exact C programming style.  Smart indent
is programmed in terms of macros in the NEdit macro language which can be
entered in: Preferences -&#62; Default Settings -&#62; Indent -&#62; Program Smart
Indent.  Hooks are provided for intervening at the point that a newline is
entered, either via the user pressing the Enter key, or through
auto-wrapping; and for arbitrary type-in to act on specific characters typed.
</P><P>
To type a newline character without invoking smart-indent when operating in
smart-indent mode, hold the Shift key while pressing the Return or Enter key.
</P><P>
<H3>Auto-Indent</H3>
</P><P>
With Indent set to Auto (the default), NEdit keeps a running indent.  When
you press the Return or Enter key, spaces and tabs are inserted to line up
the insert point under the start of the previous line.
</P><P>
Regardless of indent-mode, Ctrl+Return always does the automatic indent;
Shift+Return always does a return without indent.
</P><P>
<H3>Block Indentation Adjustment</H3>
</P><P>
The Shift Left and Shift Right commands as well as rectangular dragging can
be used to adjust the indentation for several lines at once.  To shift a
block of text one character to the right, select the text, then choose Shift
Right from the Edit menu.  Note that the accelerator keys for these menu
items are Ctrl+9 and Ctrl+0, which correspond to  the right and left
parenthesis on most keyboards.  Remember them as adjusting the text in the
direction pointed to by the parenthesis character.  Holding the Shift key
while selecting either Shift Left or Shift Right will shift the text by one
tab stop (or by one emulated tab stop if tab emulation is turned on).  The
help section "Shifting and Filling" under "Basic Operation" has details.
<P><HR>
</P><P>
<A NAME="Syntax_Highlighting"></A>
<H2> Syntax Highlighting </H2>
</P><P>
Syntax Highlighting means using colors and fonts to help distinguish language
elements in programming languages and other types of structured files. 
Programmers use syntax highlighting to understand code faster and better, and
to spot many kinds of syntax errors more quickly.
</P><P>
To use syntax highlighting in NEdit, select Highlight Syntax in the
Preferences menu.  If NEdit recognizes the computer language that you are
using, and highlighting rules (patterns) are available for that language, it
will highlight your text, and maintain the highlighting, automatically, as
you type.
</P><P>
If NEdit doesn't correctly recognize the type of the file you are editing,
you can manually select a language mode from Language Modes in the
Preferences menu.  You can also program the method that NEdit uses to
recognize language modes in Preferences -&#62; Default Settings -&#62; Language
Modes....
</P><P>
If no highlighting patterns are available for the language that you want to
use, you can create new patterns relatively quickly.  The Help section
"<A HREF="#Highlighting_Patterns">Highlighting Patterns</A>" under "Customizing", has details.
</P><P>
If you are satisfied with what NEdit is highlighting, but would like it to