How to get a single character without pressing Enter in Elixir? - io

Similar with Ruby's STDIN#getch.
Elixir's IO.gets/2 needs to press enter to get the character. Is there a way to get a single character without pressing Enter in Elixir?

Whenever I try implementing non-trivial interactions with stdio in pretty much any language, ncurses pops up. So I'd take a look at this NIF https://github.com/jfreeze/ex_ncurses

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Is there a one-liner to tell vim/ctags autocompletion to search from the middle of a word?

In vim (in Insert mode, after running exuberant ctags), I am using ctrl-x followed by ctrl-] to bring up a dropdown of various possible words/tokens. It's a great feature.
The problem is that by default, this list starts with a bunch of numeric options and automatically inserts the first numeric option, and if I backspace to get rid of the numbers and start typing a part of a word fresh -- with the idea of searching from the middle of the word -- the autocompletion behavior exits entirely.
I know I could type the first letter of the word that I want, then go from there. But that assumes that I know the first letter of the word, which is not necessarily a given.
For example, if I'm working on a pair-programming project with a friend during a long weekend, I might not remember at any given moment whether he called his method promoteRecordStatus(), updateRecordStatus() or boostRecordStatus(). In this example, I would like to type RecordStatus and get the relevant result, which does not seem to be possible at a glance with the current behavior.
So with that scenario in mind: Is there a simple, vim-native way to tell the editor to start its autocompletion without any assumptions, then search all available tokens for my typed string in all parts of each token?
I will of course consider plugin suggestions helpful, but I would prefer a short, vim-native answer that doesn't require any plugins if possible. Ideally, the configuration could be set using just a line or two.
The built-in completions all require a match at the starting position. In some cases, you could drop separator characters from the 'iskeyword' option (e.g. in Vimscript, drop # to be able to complete individual components from foo#bar#BazFunction()), but this won't work for camelCaseWords at all.
Custom :help complete-functions can implement any completion search, though. To be based on the tags database, it would have to use taglist() as a source, and filter according to the completion base entered before triggering the completion. If you do not anchor this pattern match at the beginning, you have your desired completion.

Emacs / vim quick copy paste

I'm trying to make a transition to emacs (using evil mode/vim keybindings) and I'm having a hard time feeling more efficient/productive than if I just used the mouse. Here is an example of a situation where I find myself really slow:
for i in range(self.allData.shape[0]):
self.correctSequence = self.displayNumbers(i, self.allData)
self.userSequence = self.numberEntry()
self.allData.set_value(i, 'userSequence', ''.join(self.userSequence))
if len(self.correctSequence) != len(self.userSequence):
self.allData.set_value(i, 'correct', 0)
else:
if list(reversed(self.correctSequence)) == self.userSequence:
self.allData.set_value(i, 'correct', 1)
else:
self.allData.set_value(i, 'correct', 0)
It would be very common for me to have to change the first 4 instances of self.allData to something else (self.testData, for example), leaving the last 2 untouched.
Normally this wouldnt be too bad with a mouse. For example, I could replace the first allData with testData, copy it, use the mouse to the next 3 occurences and just hit CTRL-V for each one. Or better yet, just use multiple cursors in sublime/atom and replace all 4 in one go
I use spacesmacs in emacs with vim keybindings. So, in emacs I find myself having to do something like the following:
SPC-SPC a (avy jump to words beginning with a)
cw testData
Repeat those 2 steps once for each word I want to replace
This seems really inefficient and I'm wondering: am I just using an inefficient method? Is there a faster way to do what I want?
It seems that even if I managed to complete those steps really fast (4 times), theres still A LOT more typing one would have to do, and I fail to see how this would be faster than just reaching for the mouse. Yes, one could make the argument that I'm losing time by constantly reaching for the mouse, but in my mind I'm saving typing time by reaching for the mouse because I can just hit CTRL-V a few times to achieve what I want. Where exactly are the vim speed gains in a situation like this?
If you just want to replace, you can use query-replace, and replace the word one by one.
You can use replace-string too, but remember to limit replacement to part of the buffer, activate the region around that part.
Anyway, these commands could prevent you from finding the word by your eyes, moving cursor by mouse and moving your hand back to keybaord. And they could avoid probable overlook too. At least I don't want to leave my hands from the keyboard when typing. :)
I'm not sure how "vim-like" Spacemacs is, but you could do it like this in Vim:
/all<CR>
cgntest<Esc>
.
.
.
or:
/all<CR>
cetestData<Esc>
n.
n.
n.
or:
:,$s/allD/testD/gc<CR>
Maybe one of these methods works in Spacemacs too?
In addition to the usual (and generally the best) answer, query-replace (see #songyuanyao's answer), you can use the secondary selection to advantage to selectively paste the same thing at various places. Unlike the region, the secondary selection is unrelated to the cursor position (aka point), so it is always available regardless of where the cursor is.
And unlike query-replacing, you can paste it on demand, instead of having to answer for each matching occurrence. If you use delete-selection mode then just select some text to replace and paste the secondary selection to replace it.
You can set and paste the secondary selection using the mouse - see Secondary Selection on the Emacs Wiki, and see the Emacs manual, node Secondary Selection.
If you use library second-sel.el then you can use the secondary selection from the keyboard as well, and get a lot more use out of it.

altering Vim's text input behavior

[Edit: after reading comments I realize that the Surround plugin is adequate for my needs after all, so I'll leave this question for purely academic purposes to gain a better understanding of vimscript's inner workings]
I'd like to make adding/deleting tags, quotes, braces, and other symmetrical text structures easier to do in Vim, and I find the surround.vim plugin a little too quirky and specialized for my needs.
What I really need is more generally a "mirrored" input mode and "mirrored" deletion mode, whereby I could visually select a block of text, then type onto or delete from both ends of the selection at once. As an example workflow, I'd like to:
select the word hello
hit some keystroke combo to enter "mirror mode"
type "
my text now says "hello"
In this example I only typed one character at each end, but it's important that in step three I could have typed many characters, not just one, for instance I should be able to type <b> to produce <b>hello<b> (I still would need to manually add the / in the closing tag, which I'm OK doing).
So is this even possible in Vim? Could someone provide a broad outline of functions that would be involved in the solution? Specifically, I don't know how to intercept text as it's being inserted and then alter the location where it appears so that it's tacked onto the beginning and ending of the selection block instead of the cursor location. And ditto for deletion.
Well, the behavior you describe is exactly what Surround does:
select the word hello
hit S
type "
my text now says "hello"
The difference with what you ask is the "live updating" or "live mirroring" which I have no idea how to do. You could probably take a look at SnipMate or UltiSnips for that part.

Get the last search or search&replace string back in vim?

How can I bring back the last string I used for a search or a search&replace?
For example, assume that I enter :%s/some_text/some_other_text/gc and vim gives me the E486: Patterns not found: some_text error message back. I then realize that I actually meant to write some_magic_text instead of some_text. At that point, how can I get back my original string in the bottom command row (or whatever it is called) so I can change it and do a second search? Is there a nifty little command for that?
In this brief example it looks unnecessary, but when the text you are looking to replace is mighty long and you just typed one letter wrong, it is fantastically annoying to have to retype everything.
And I am using MacVim if that makes any difference.
From the normal mode, hit q/ to navigate through your search history!
Check out this vimvcast which explains what you want.
More generally, you can recall any command you have previously typed by entering the first few characters, and then use arrow multiple times to navigate in history.
In your case, you could type:
:%s<Up>
See :help history
This answer might be good an improvement to what you are after, after all.
Use search with highlighting, to interactively check if the regex you are crafting is definitely working, and then use it in a search-replace.
:se is (incsearch, better put se is in your .vimrc)
/<search term>
check with n/N if you are happy with the matches
:s%//<replace term>/g
When omitting the <search term> in the search-replace in 4., the last used search will be used.
For acessing the list of last (search-replace) commands use q:, or as already noted q/ for the list of last search terms.
Bonus:
When using :se gd, s/<search>/<replace> will behave as s/<search>/<replace>/g.
Accessing just the first search match in each line can then still be done with adding /g, so essentially both behaviours are just switched.
/ and then up to bring up the last search query.

In bash, how to make control-delete mean kill-word?

Bash uses readline, and readline can delete the word to the right of the cursor with "kill-word".
The problem is in recognizing the keypress of control-delete. When I press them in bash, "5~" is output on the screen. I could just bind for this, but it would mean that one day I need to type "5~", and it deletes a word to the right instead! So I'd much rather discover the correct control sequence.
I have googled, and quite a few resources discuss the "delete" key, but none that I've found discuss "control-delete" key. I've experimented with many variations, but nothing works.
The worst is the hours I've spent on this tedious, mindless grind, when it really should be a non-problem.
EDIT: It's through X, so maybe there's a solution with xev and xmodmap
On my machine, pressing Ctrl-V, Ctrl-Delete outputs this:
^[[3;5~
The ^[ escape character can be replaced with \e, so you can then use bind like this for bash (in your ~/.bashrc for example):
bind '"\e[3;5~":kill-word'
Or, you can add the following to your ~/.inputrc so Ctrl-Delete does kill-word in any program that uses readline:
"\e[3;5~": kill-word
This will bind only the Ctrl-Delete key, you don't have to worry about what will happen if you need to type 5~.
What you see is not the whole truth. It's probably <ESC>5~ or something like that. Try Ctrl-V Ctrl-Delete. The Ctrl-V means "do not interpret the next thing".
So binding <ESC>5~ that should be pretty safe.
Alt+D deletes one word to the right of the cursor
Ctrl+W deletes one word to the left of the cursor
(both are based on Emacs, I believe)
If you type ^Q^V (that's Control-Q followed by Control-V, releasing the Control key between them is fine), and then press Control-Delete, do you get the output you mentioned? I just tried it, and at least using Putty I don't get a response at all. Perhaps the behvior is different on an actual Linux console, though.
For other keys, readline prints a longer sequence, often including a special "command sequence introduction" character, which is hard to type by mistake. Try it, and see if you get a longer sequence with the ^Q^V command (which is, btw, called quoted-insert).
For example, if I press ^Q^V and then Delete (without control held down), readline prints ^[[3~. This tells me I can bind stuff to the Delete key by saying \e[[3~. It seems highely likely that the CSI character is present for you, but you're not seeing it since you're not asking readline to quote the input properly.
Ctrl-W deletes words.
Ctrl-u deletes lines.
They're based on Emacs (M-w and M-u).

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