I'm trying to search & replace inside my file for all occurrences of a particular pattern, then call toupper() on each match. In practice, there aren't that many occurrences that I couldn't just do this by hand, but I'm curious to improve my Vim skills and find a (simple) way to get Vim to do this for me. I say simple, otherwise I'll just forget.
From a read over the Vim help for s/, I should be able to do something like this:
:%s/\vfunction ([a-z0-9_]+)/\="function " . toupper("\1")/g
(Assuming I'm uppercasing all function definition names).
This actually just replaces the function names with the control character ^A though. How do I refer to the capturing group in the regexp?
Apologies. I should read more closely. I'll answer my own question anyway, instead of deleting it. You need to use submatch(n) to refer to the capturing group:
:%s/\vfunction ([a-z0-9_]+)/\="function " . toupper(submatch(1))/g
Use \U in the replacement pattern.
:%s/\vfunction ([a-z0-9_]+)/function \U\1/
Related
I am trying to use substitute command in vim to enclose all occurences of a particular pattern
\cite{author1}
\cite{author2}
with
(\cite{author1})
(\cite{author2})
Based on other answers in stack exchangeI used the following vim command
%s/\\cite{(\w\+)}/(\\cite{\1})/g
But, no luck. It says "no matches found". I put two back slashes, one of which is supposed to be the escape character. Kindly help.
I know I could use some other editor and finish the job, but I want to know my mistake. Thank you.
please escape ()
%s/\\cite{\(\w\+\)}/(\\cite{\1})/g
You do not need a capture group to get the entire match. You can use \0 or & for the whole match in the replacement portion of your substitution.
:%s/\\cite{\w\+}/(&)/g
If you do want to use a capture group, then you need to escape the capture group/parenthesis.
:%s/\(foo\)/(\1)/g
For more help see:
:h :s%
:h /magic
As mentioned, normally you need escape the parentheses.
You can use very magic mode (\v) to make the regex simpler; removing the need to escape lots of the regex parts, including the parentheses for capturing:
%s/\v(\\cite\{\w+\})/(\1)/g
Knowing what every sign in a regular expression does in vim is sometimes very
difficult, especially for all the modes and configuration variables that this
depends on. For that reason, it is very important to have visual feedback about
what text are we really matching in any moment while crafting regular
expressions.
If you work with neovim, there is a special option called inccommand that you
can enable to live preview the matches and substitution. That way you can figure
out you errors more quickly. This feature is very likely to be included also in
vim in the future, but independently of that, you can also use simple vim to
give you visual feedback if you enable the option incsearch.
With incsearch set, you can watch the matches of / and ? while you write them
just to be sure that the pattern is correct. Later you can exploit a nice
feature from the substitution: if you leave the first section empty, the last
search will be used.
So you could first make the search:
/\\cite{\w\+}/(&)/g
In the meantime, vim will be showing you the matched text visually. Once you
are sure that the pattern is correct press enter, and finally type:
:%s//(\1)<Enter>
Also, in case you want something more powerful than this simple hack, you can go
for my plugin Extend.vim, that can
do that and much more with great visual feedback.
Say I want to remove all comment blocks in my source code without deleting the whole lines they are on.
It's possible to achieve this using the
:%s/\/\*.*\*\//
command. I was wondering, is there a specific delete command for this, or is replacing the matched pattern the best approach? The difference most likely wouldn't be much, I'm just curious.
Replacing with nothing really is the idiomatic 'delete this pattern' operation.
:%s/pattern//g
If you want to blank all lines that contain a pattern, like in your example, the obvious solution is to add wildcard matches around the pattern.
:%s/.*pattern.*//
An alternative is to use :global with a normal mode or Ex command. These two achieve the same thing:
:g/pattern/normal! S
:g/pattern/delete|put! _
By the way, while I don't recommend using abbreviated command names in scripts or in code that other people might see, I think it's fine to use them interactively. Thus I tend to abbreviate such commands as :g/pattern/norm! S and :g/pattern/d|pu!_.
I am using vim to edit structured text files.
Sometimes I use search-and-replace feature, and sometimes I am better off with search, followed with a macro, in which case I have several macros at hand, and the choice of one depends upon the particular search result.
In both cases, though I have to spend some effort to arrive at an acceptable regex to satisfy my editing needs. As the regexs are often very long and sophisticated, I end up with both command-line history and search history full of my trial-and-error by-products. The correct regex is not always the last one in a series of attempts, so if I want to reuse the hard-earned regex in a similar editing situation, I have to dig through the pile again.
In search-and-replace scenario I have quickly fixed this with comments that I now put in place at the end of a would-be reusable search-and-replace command string, for example:
:%s/very_long_and_sophisticated_regex/another_long_and_sophisticated_regex/gc "comments on what this search and replace command does and how it might be reused
This way I can easily ignore the piles of stuff in my command line history and quickly find relevant re-use candidates, they are shown in different color. The commands are reusable right away, comments are ignored.
Not so with the search history, though.
Having rtfmed and searched the web, I have not found anything similar. At the moment I put quasi-comments using XXX at the end of reusable search strings, for example:
/search_string_containing_very_long_and_sophisticated_regex XXX comments on what it finds and how it might be re-used
This way I can at least find the right string for re-use, but I have to first delete 'XXX' and the comments.
I wonder if there is a more elegant way of commenting the search strings in search history, similar to command-line history.
You used the word "elegant" in your title, and that I don't have on offer. If instead you can also accept a quirky workaround that relies on Vim internals, here's one.
To restate your problem, it is possible to add comments after Ex :commands,
:AComplicatedExCommand -42 -quux " this fizzes the brobble
:HardToRememberCommand test.txt " use this to brew the framble
but the same is not possible for complicated search /queries (or ?queries).
I've just discovered that you can trick Vim by terminating your search query with a literal null byte:
/[Complicated]*regexp/^# this regexp finds all scrobbles
/another\+Rege\x*p/^# use this to search foo bars
The ^# here is a literal NUL. You can enter it by pressing CtrlV and then 000.
Vim will ignore everything after the null byte, but it'll still show the whole line in the search history, including the "comment".
You can add a regexp branch that never matches, e.g. /\%$indicator\|search string
\%$ is a special Vim atom matching the end of the file. Since that will never match when followed by the indicator text, the first branch (up to \|) will never match and therefore can represent your indicator.
I've created the TaggedSearchPattern plugin to make adding the tag and recalling it even easier.
I have several functions that start with get_ in my code:
get_num(...) , get_str(...)
I want to change them to get_*_struct(...).
Can I somehow match the get_* regex and then replace according to the pattern so that:
get_num(...) becomes get_num_struct(...),
get_str(...) becomes get_str_struct(...)
Can you also explain some logic behind it, because the theoretical regex aren't like the ones used in UNIX (or vi, are they different?) and I'm always struggling to figure them out.
This has to be done in the vi editor as this is main work tool.
Thanks!
To transform get_num(...) to get_num_struct(...), you need to capture the correct text in the input. And, you can't put the parentheses in the regular expression because you may need to match pointers to functions too, as in &get_distance, and uses in comments. However, and this depends partially on the fact that you are using vim and partially on how you need to keep the entire input together, I have checked that this works:
%s/get_\w\+/&_struct/g
On every line, find every expression starting with get_ and continuing with at least one letter, number, or underscore, and replace it with the entire matched string followed by _struct.
Darn it; I shouldn't answer these things on spec. Note that other regex engines might use \& instead of &. This depends on having magic set, which is default in vim.
For an alternate way to do it:
%s/get_\(\w*\)(/get_\1_struct(/g
What this does:
\w matches to any "word character"; \w* matches 0 or more word characters.
\(...\) tells vim to remember whatever matches .... So, \(w*\) means "match any number of word characters, and remember what you matched. You can then access it in the replacement with \1 (or \2 for the second, etc.)
So, the overall pattern get_\(\w*\)( looks for get_, followed by any number of word chars, followed by (.
The replacement then just does exactly what you want.
(Sorry if that was too verbose - not sure how comfortable you are with vim regex.)
I am using Vim to read through a lot of C and Perl code containing many single letter variable names.
It would be nice to have some command to change the name of a variable to something more meaningful while I’m in the process of reading the code, so that I could read the rest of it faster.
Is there some command in Vim which could let me do this quickly?
I don’t think regexes would work because:
the same single letter name might have different purposes in different scoping blocks; and
the same combination of letters could be part of another longer variable name, a string literal, or a comment.
Are there any known solutions?
The following is how to rename a variable which is defined in the current scope {}.
Move your cursor to the variable usage. Press gd. Which means - move cursor to the definition.
Now Press [{ - this will bring you to the scope begin.
Press V - will turn on Visual Line selection.
Press % - will jump to the opposite } thus will select the whole scope.
Press :s/ - start of the substitute command.
<C-R>/ - will insert pattern that match variable name (that name you were on before pressing gd).
/newname/gc<CR> - will initiate search and replace with confirmation on every match.
Now you have to record a macros or even better - map a key.
Here are the final mappings:
" For local replace
nnoremap gr gd[{V%::s/<C-R>///gc<left><left><left>
" For global replace
nnoremap gR gD:%s/<C-R>///gc<left><left><left>
Put this to your .vimrc or just execute.
After this pressing gr on the local variable will bring you to :s command where you simply should enter new_variable_name and press Enter.
I know it's an old question, and #mykola-golubyev's way obviously IS the best answer for the particular case in the OP question (which, I assume is going through obfuscated code where you're likely to have multiple blocks with same var names); but with the question name like that many people coming here from google searches probably look for less situation-specific ways to rename variables in VIM -- and those can be more concise
I'm surprised no one suggested this way:
* :s// NEWNAME /gc
The * is the same as gn - search the next occurrence of the word under the cursor AND make it the last searched pattern; you can then omit the search pattern in the substitute command and VIM will assume that last one is the pattern to search for.
For small amounts of var copies, here's an even quicker one:
* cw NEWNAME <esc> then repeat n. for other occurrences
* is search for occurrences, cw is change word, n goes to the next occurrence of the last searched term and . repeats the last command (which is now change word to NEWNAME)
(Credits for me knowing all this go to #doomedbunnies on Reddit)
Another cool trick: (credits to #nobe4)
* cgn NEWNAME <esc> then repeat . for other occurrences
cgn is "change whatever is the result of (find next occurrence)". Now that this is the last command, you don't need the n to go to the next occurrence, so fewer strokes again, and, more importantly, no need to alternate n and .. But, obviously, this one has the drawback of not having a way to skip an occurrence.
Here are some benefits of these over other similar approaches, or language-specific plugins with refactoring support:
no command mapping, no fiddling with .vimrc(or init.vim), so you can use it in any VIM copy you come across (e.g. a quick task on some VPS or your friend's machine where configuring VIM your way would defeat the purpose of 'quick')
using * or gn for word selection is very quick -- just one keystroke (well, let's say 1.5)
using * or gn makes sure you don't get any matches inside other words, just as :%s/<C-R>//gc does. Beats typing the :%s/\<OLDNAME\>/NEWNAME/gc by hand: I personally tend to forget to use the \< things to limit matches to whole words only.
Not using a scope will only result in a few extra strokes of n to skip unwanted matches -- probably even fewer than the extra strokes needed to limit the scope to a certain code block. Under normal circumstances, your variables are most likely somewhat localised to a certain code block anyway.
AFAIK, there is no actual refactoring support in VIM. When doing a rename with the intent of a refactor I usually take the following precautions:
Limit the scope of the change my using marks.
When entering the regex, bracket the name with \< and >. This will make it match an entire word which reduces the types of incorrect renames that will occur.
Don't do a multiline replace to reduce chances of a bad replace
Look through the code diff carefully if it's anything other than a small change.
My end change looks something like this
:'a,'bs/\<foo\>/bar
I would love to be wrong about there not being a refactoring tool for VIM but I haven't seen it.
Put this in your .vimrc
" Function to rename the variable under the cursor
function! Rnvar()
let word_to_replace = expand("<cword>")
let replacement = input("new name: ")
execute '%s/\(\W\)' . word_to_replace . '\(\W\)/\1' . replacement . '\2/gc'
endfunction
Call it with :call Rnvar()
expand("<cword>") gets the word under the cursor. The search string uses % for file-scope, and the \(\W\) patterns look for non-word characters at the boundary of the word to replace, and save them in variables \1 and \2 so as to be re-inserted in the replacement pattern.
You could use the 'c' modifier in the global search and replace that would ask you for confirmation for each replace. It would take longer but it might work for a non-humongous code file:
%s/\$var/\$foo/gc
The c stands for confirm.
In c, you may be able to make some progress using cscope. It makes an attempt at understanding syntax, so would have a chance of knowing when the letter was a variable.
If this is across multiple files, you may consider taking a look at sed. Use find to grab your files and xargs plus sed for a replace. Say you want to replace a with a_better_name in all files matching *.c, you could do
find . -name "*.c" | xargs sed -i -e 's/a/a_better_name/g'
Bear in mind that this will replace ALL occurrences of a, so you may want a more robust regex.