How can I write a "," (comma) character in the SLIME emacs window? The , key brings up the SLIME command prompt automatically.
Thanks, a Lisp beginner
, only triggers REPL shortcut selection when input at the beginning of a line. In all other cases, you can input a comma by typing ,.
In the case of Common Lisp, since as long as you don't modify the reader, , can only occur within a quasi-quoted expression, this should not be a significant restriction.
If it really is a problem, refer to Deokhwan Kim's answer.
You can insert , by C-q, (Control-q and then comma). C-q is bound to quoted-insert, which can be generally used whenever you want Emacs to read a next input character and insert it instead of invoking a command bound to the input character.
Related
Even the basic things seem to be hidden behind weird shortcut-combinations.
How can I (hopefully without too many c-m-x-c combinations) create a simple new line?
return evaluates the current line
With C-j. That said, if you have paredit enabled, it should do all the newlines you need automatically.
In my case it was M-j.
I'm currently trying out SpaceMacs, not sure if that has anything to do with it.
Even the basic things seem to be hidden behind weird shortcut-combinations.
If you don't want RET to have contextual behaviour, you can M-x customize-option RET ielm-dynamic-return.
How can I ... create a simple new line?
Only a newline? C-qC-j is the normal way to enter a newline in places where RET does something else. (More generally you can use C-q to insert any character that isn't self-inserting for the current buffer.)
If you want newline + indentation (which is what RET does when contextually appropriate), then M-j will do that (noting that if you are in a comment at the time then the new line will also default to a comment).
I am slightly confused by the difference between keys and key-bindings in emacs after reading the first chapter of "Writing GNU Emacs Extensions" (O'Reilly book).
The chapter starts by noting that in some emacs version the keys backspace and DEL, invoke the help menu instead of deleting. In other words, they invoke what is invoked by C-h.
The chapter then goes on to show how to change this behaviour using Lisp code. This is done by binding the keystroke C-h to the delete command.
This is a bit confusing to me. In my mind DEL, Backspace and C-h are three different keystrokes (the first two consisting of a single key).
Why does remapping C-h effect what DEL and Backspace does?
I would have thought to change what backspace does for example, you would remap backspace to another command, not the keystroke C-h.
Unless remapped by a low-level keybord driver, the effect of the Backspace key is to send the character with numeric code 8, which, in certain operating systems, is exactly the same code generated by pressing Control-h. You can verify this fact by simply writing anything on a unix (or linux) shell and then pressing Backspace and Control-h: both of them have the effect of erasing the previous character, since the character with numeric code 8 is interpreted by the operating system as the control character BS, backspace, used either to erase the last character printed or to overprint it (see wikipedia). Analogously, Control-J is equivalent to the RETURN key, etc.
The same Wikipedia page describe DEL as “originally intended to be an ignored character, but now used in some systems to erase a character”.
So, when you assign a command to a keystroke you are actually assigning a command to a character code, and if two or more keys generate the same code, by pressing them you are invoking the same command.
#Renzo answered your question about how these keys are related and how binding one can seem to affect another. Here is some more information about what's going on in this particular case.
See the Emacs manual, node DEL Does Not Delete.
There you will see this, following an explanation of the problem/confusion:
To fix the problem in every Emacs session, put one of the following
lines into your initialization file (*note Init File::). For the first
case above, where BACKSPACE deletes forwards instead of backwards, use
this line to make BACKSPACE act as DEL:
(normal-erase-is-backspace-mode 0)
For the other two cases, use this line:
(normal-erase-is-backspace-mode 1)
Another way to fix the problem for every Emacs session is to
customize the variable normal-erase-is-backspace: the value t
specifies the mode where BS or BACKSPACE is DEL, and nil
specifies the other mode. *Note Easy Customization::.
See also the GNU Emacs FAQ question about Backspace invoking help. There you will see, in addition to information similar to that above, information about how to remap DEL on UNIX - use this:
stty erase '^?'
Wrt C-j and RET (not mentioned in the question, but mentioned in #Renzo's answer): The default behavior of Emacs changed in most programming modes, in Emacs 24.4.
Starting with that release, electric--indent-mode is turned on by default, which means that RET inserts a newline character and indents, whereas C-j just inserts a newline character. Prior to that release, these keys had the opposite behaviors. If you prefer the old behavior then do this, to turn off electric-indent-mode:
(when (fboundp 'electric-indent-mode)
(electric-indent-mode -1)) ; Use classic `C-j' and `RET'.
I have a text file which I am only able to look that there is an underscore between some words only using emcas editor but not other editors such as vi. I do not know how to use emacs but I wanted to replace these underscores "_" by space in the emacs editor automated fashion. How can I do that ?
I believe that those underscore aren't really underscore, but non breaking space (U+00A0 unicode char), that Emacs show as underscore with a different color. You probably don't need to replace them, but if this is really needed, just use M-x replace-string and kill and yank one of those non-breaking space in the string to be replaced.
Hit the M-x key-combination (that is, hold meta key - alt on windows - and hit x) type replace-string and hit enter. You can then type [underscore] enter [space] enter.
In Emacs notation:
M-x replace-string RET _ RET " "
Should the previous answer not solve it: Remember that as a coding system error. Check with C-x = if it's char 95.
If not, check variables coding-system-for-read, coding-system-for-write, buffer-file-coding-system
Finally, get emacs core developers at help-gnu-emacs#gnu.org
I have 2 columns, separated by comma. How can I swap those columns with Emacs?
I have the following:
column 1,column2
x1,x2
y1,y2
f1,f2
and I want it like this:
column2,column 1
x2,x1
y2,y1
f2,f1
Use M-x query-replace-regexp and then:
\(.+\),\(.+\)
as replace regexp and
\2,\1
for replacement.
In Emacs, you need to escape grouping parentheses with \. So, above regexp would be usually written as
(.+),(.+)
which means that you want everything before comma in first group and everything after comma in second group.
\2,\1
means: write second group, then comma, then first group.
While you can apply techniques given by other people, you can also use the org-mode tables.
Once you convert the data into org-mode table, it is very easy to swap the columns by simple keystrokes. You can have M-x org-mode, select the region then do M-x org-table-convert-region, and then M- on the right most column. I am not sure, how to export the data as CSV, but that should be very easy for you with replace-regexp. This can be helpful: http://www.gnu.org/software/emacs/manual/html_node/org/Tables.html#Tables
Similar to the answer given by #darioo, type the following into the top of your buffer:
(query-replace-regexp "\\(.*?\\),\\(.*\\)" "\\2,\\1")
Then, put your cursor at the end of this line and press ctrl-x, ctrl-e.
You will have an interactive search-and-replace for which you press the space bar to make the change, and press ctrl-g to quit. If you press ! (exclamation mark) then the search will cease being interactive and take place on all matching text.
If you want to reverse the changes then press M-x (usually ESC followed by x) and type undo and press enter.
Emacs has a rectangular selection mode, see for example: http://emacs-fu.blogspot.com/2008/12/working-with-rectangular-selections.html
Even better, if you enable cua-mode, entering Ctrl-Enter will put you in rectangle selection mode that is very easy to use.
http://trey-jackson.blogspot.com/2008/10/emacs-tip-26-cua-mode-specifically.html
Use a macro !
Go to the first line of the buffer
Start recording a macro (F3)
Move to the beginning of the line (^a)
Search for comma (^s ,)
Transpose (M-t)
Move cursor down one line
Stop recording macro (F4)
Select the rest of the lines and:
M-x apply-macro-to-region-lines
UPDATE: This doesn't work properly if you have multiple words in a column. Looking for a more general solution...
In GNU screen, I want to change the default command binding to Alt-s (by tweaking .screenrc) instead of the default C-a, the reason is I use emacs hence GNU screen binds the C-a key, sending "C-a" to the emacs becomes tedious (as #Nils said, to send "C-a" I should type "C-a a"), as well as "C-a" in bash shell, and I could change the escape to C- but some of them are already mapped in emacs and other combinations are not as easy as ALT-s . If anyone has already done a ALT key mapping, please do let me know.
It is possible to work around :escape command limitations using registers and :bindkey command. Just put this in .screenrc:
# reset escape key to the default
escape ^Aa
# auxiliary register
register S ^A
# Alt + x produces ^A and acts as an escape key
bindkey "^[x" process S
## Alt + space produces ^A and acts as an escape key
# bindkey "^[ " process S
See http://adb.cba.pl/gnu-screen-tips-page-my.html#howto-alt-key-as-escape
From my reading of man screen it seems like the only meta character that screen can use for the command binding is CTRL:
escape xy
Set the command character to x and the character generating a literal
command character (by triggering the "meta" command) to y (similar to
the -e option). Each argument is either a single character, a two-character
sequence of the form "^x" (meaning "C-x"), a backslash followed by an octal
number (specifying the ASCII code of the character), or a backslash followed
by a second character, such as "\^" or "\\". The default is "^Aa".
If there is some mapping that you don't use in emacs, even if it's inconvenient, like C-|, then you could use your terminal input manager to remap ALT-X to that, letting you use the ALT binding instead. That would be a little hackish though.
I'm an Emacs and screen user as well. Although I rarely use Emacs in a terminal -- and as such in a screen session -- I didn't want to give up C-a for the shell either (which uses Emacs key bindings). My solution was to use C-j as the prefix key for screen, which I was willing to sacrifice. In Emacs programming modes it is bound to (newline-and-indent) which I bound to RET as well, so I really don't miss it.
By the way: I know this is an advise rather than an answer, but I felt this would be valuable enough to post nevertheless.
To make Alt+X the default prefix for commands and free C-a, add the following lines to .screenrc:
escape ^||
bindkey "^[x" command
As a side effect C-| will be command prefix too. If you need this keys to be free too, then fix "escape ^||" accordingly.
Screen doesn't have any shorthand syntax for alt bindings, but you can give it the octal code directly. For instance on my machine, Alt-x has the hex code F8, or 370 octal, so putting
escape \370x
in my screenrc changed the escape code to alt-X
Tested and works with screen 4.00.03 on Linux.
You may have to change the escape, since I think this may depend on things like your language and codeset, etc: how I found out what my escape code was was to type
$ echo -n ^QM-x | perl -ne 'printf "%lo\n", ord($_)'
^Q is the quoted-insert command for readline (it inserts what you type directly without trying to interpret it) and M-x was a literal Alt-X.
Fellow emacs user here.
The best solution I've found is a ~/.screenrc file with the following:
# C-a :source .screenrc
escape ^gg
Live updated here: https://gist.github.com/1058111
See also: http://ubuntuforums.org/showthread.php?t=498675
Something I have had for years in my .screenrc:
escape ^Zz
which is now hardwired in muscle memory for me.
Somehow I ended up having to share a screen with someone else's config, and now I keep stopping processes all the time (bash ^Z)... Not funny...