Set foldlevel in part of file in vim - vim

Setting foldlevel when folding is active displays all folds up to that level and closes the rest.* I would like to do something similar for only part of the file, perhaps all material below the current fold or all material in a range.
Consider this file:
Tippy Top
chapter
section
subsection
chapter 2
section 2.1
sub 2.1.1
where the leading white space is tabs and :setlocal foldmethod=indent is in effect.
I would like to go to Tippy Top and do something like :expandToLevel 1 and see only the 2 chapter headings.
I can use zC to close everything, but zo simply restores the previous view, with lower level headings like subsection expanded if they were expanded earlier.
I've tried using :foldclose, repetition counts, highlighting a visual region, za, foldnestmax, but none achieve the behavior I want.
So far, to get expansion to a certain level only, I use one of 2 methods:
Use :set foldlevel to get what I want in my current area, thereby wiping out whatever custom folds I've done elsewhere.
Manually close the folds I want closed, e.g., zc on chapter and chapter 2.
The first loses what I've done in the rest of the document and the second is slow and tedious when there are more then a few entries.
I notice that the C function foldUpdateIEMS() and related functions take a range of lines. I'm not sure what the function does, but something like that doesn't seem to be exposed to vim scripts.
Apr 25 update: got vim running in a debugger and put a breakpoint on foldUpdateIEMS(). It fired when loading the file, but not when I :set foldlevel=2. So it does not seem to be directly involved in opening and closing folds. It does seem to define the folds.
My interest in these functions comes from vimoutliner, which uses foldmethod=expr. But I simplified to a plain text file with tab indentation to focus on the essential issues.
*As a side issue, when I set foldlevel=1 with the test file above I only see chapter, not chapter 2. I don't know why.

I would like to go to Tippy Top and do something like :expandToLevel 1 and see only the 2 chapter headings.
:set foldlevel=1
does just that:
or you could do 2zm (you may need :set folminlines=0). I don't like to count so I would simply do something like zM to close everything, and then zr to open one level.

Related

How to remove tabs on multiple rows at once

This is not a programming question but an inconvenience in the android-studio editor.
If you have an unwanted tab before all your lines, how can you remove them all at once? Now I have to manually go over 50 lines to remove all the tabs to make my code look clean.
If you want to add multiple tabs at once you just select all your code and press the tab button. So I'm looking for the reverse of that.
If I understood you right, you want to beautify the code itself. Fortunately, you don't have to do that manually - at all.
There's a keybinding for it, which may vary by your OS and which layout you use by default. Go to file -> settings -> Keymap and search for auto-indent. Here's what I get on Windows 10 with the default keymap:
Again, which you have may depend on OS (I'm assuming that mainly applies to Mac though) and your keymap, but you can automatically indent your code as per language standards using Ctrl+Alt+I.
Note that this mainly does indentation. If you chose to golf code and want to ungolf it, this will not work. At least it doesn't for Java.
However: This only works with code files the IDE or plugins support. This won't work for i.e. a .txt file out of the box.
If I misunderstood you and you only want to remove tabs without doing the auto-indent, there's at least two other options.
The first option is using multiple cursors. You can add an additional cursor with shift+alt+a mouse click where you want the cursor, or holding the mouse wheel and moving the cursor with the mouse wheel held down. There might be other methods as well, but those are the two I know of.
Once you have multiple cursors, delete the tabs just like normal. But be careful! Doing so might delete the entire line itself. If it does, you can do 1 tab/n units per indent level to the left, and press delete instead.
There's (AFAIK) no limit to how many cursors you can have at once, but you can theoretically do it with 50 lines at once if you want to. But general advice - don't add more cursors than you can see at once. These do run in parallel and it's easy to lose track if you're not careful, and you might end up deleting stuff you didn't want to delete.
And finally, the regex solution:
Note: Be careful with this. If you use it incorrectly, you might get unwanted results.
If you only want to do this in a limited area, highlight it first. Then CTRL+R and you'll be presented with the regular replace menu. Make sure Regex and In Selection are selected.
A base regex to go off is ^([\s]{2,4}|\t). Explanation just for reference:
^ - At the start of the line
(
\s{4} - Match 4 spaces
|\t - Or a tab character
)
Replace with nothing and click "replace all" (or just use the regular "replace" button if you want to double-check before you do anything). This will replace one occurrence of 4 spaces or a single tab character. If you use indentation that isn't based on 4, change the number.
This is only useable and useful if you've found yourself with incorrect indentation that's the same across all the relevant lines - it will not fix indentation mistakes and/or inconsistencies such as 3-space indentation when you want 4, or random indetation for the same block. Use the first or alternatively second method for that instead.

Vim: Is it possible to have a filtered view of a file?

In a given text file, I would like to work on a "filtered view" (hiding lines with a pattern), but still to be able to edit visible lines : the filtering would only affect the visibility of some lines, and as soon as I would reset the filter, the hidden lines would appear again.
The feature I describe could be compared to the & key in the less command (except, of course, that less can't edit the file's content) :
&some_pattern <RETURN> starts a new filter,
& <RETURN> reset the filter.
Does such a feature exist in vim, natively or as a plugin?
This usually is done with folding; you can easily define a 'foldexpr' that filters lines based on a regular expression match; see Folding with Regular Expression for implementations.
However, a single fold line will remain for each condensed block. To do away with those, I can only think of the NrrwRgn plugin, which transfers selected lines into a separate scratch buffer. It's usually only for a single block, but :help NR-multi-example suggests this works on ranges, too:
For example before editing your config file, you decide to strip all comments
for making big changes but when you write your changes back, these comments
will stay in your file. You would do it like this: >
:v/^#/NRP
:NRMulti
It can be done with plain Vim, and it's named folding. Drew Neil has two screencasts about it that you might find informative.

Vim: Hide all code around selected code

I want to be able to hide all code around the specific section of code that I am working with. Now I am wondering if this is possible in Vim somehow. I have experimented with it a bit already and have been successful at hiding lines above and below my selection by using highlight group Igore. This enables me to only see the lines that I want to focus on but the problem is when I begin to edit the code and add or remove lines. When I add a line or remove a line the already set highlight group Ignore is still maintaining the set line numbers so I either get to see some of the hidden code or some of the code that I want to see gets long and extends into the hidden line numbers. So I am wondering if there is some way to fix this or any other way to accomplish what I want in Vim?
Appreciate any suggestions!
Hiding or shading parts of the buffer is not the Vim way. Folding is the built-in feature that comes closest. With :set foldmethod=manual, you can then use zf or :fold to hide the parts above and below.
For a plugin solution, have a look at NrrwRgn - A Narrow Region Plugin. It allows you to edit parts of a buffer in a separate scratch buffer, with automatic syncing back.
To hide a range of lines (let's say from 1 to 10 and 20 to end, you can type :1,10fo|20,$fo
From there, you can create a function based on the current cursor position -10/+10
Note you have first to :set foldmethod=manual to make this works.
EDIT: a simple solution : :1,.-10fo|.+10,$fo

VIM: Respect only current code block

I have started working on a huge PHP application that has thousands of lines of code in each file, with lots of huge if blocks, classes, and functions all existing in the same file. I'm not the only dev working on it, so I cannot refactor!
I have tried using the Tags List plugin but it does not really help. Is there any way to have VIM respect only a particular code block, and ignore the rest of the file? I am hoping for some or all of these features:
Enable line numbering only for the current code block, starting from 1 at the line containing the opening {, and showing no numbering for lines preceding it or after the closing }.
Searching with / would be restricted only to the block in question.
I am thinking along the lines of selecting the current block and editing it in a new buffer when enabling the mode, then replacing the existing block with the edited block when exiting the mode. However, I am having trouble actually implementing this feature. My current version is this:
map <F7> <Esc>mO<C-V>aBy:new<Return>p:set nu<Return>:set ft=php<Return>ggi<?php<Return><Esc>
map <F8> <Esc>ggdd<C-V>aBx:bp<Return>`O<C-V>aBp
However, this has several issues, such as the inability to perform incremental saves.
I would be very surprised if Vim allows the kind of line numbering you ask for.
This plugin (and 1 or 2 similar ones IIRC) allows you to visually select a region of your current file, work on it in another buffer and put everything back in its place in the original file on :w.
Even if it's not the solution you are wanting, I think the following can help you to solve your problem.
You can use phpfolding plugin, which folds by PHP syntax (functions, classes, methods, PhpDoc...)
You can then select a fold by pressing v$ over the closed fold and execute whatever you want with :whatever. For example, :s/this/self/g to substitute all this for self in the fold. When you press :, vim will automatically add '<,'> to denote following command it's only for the visually selected text.

Context sensitive word wrap in vi/vim

How can I can specific word wrapping for specific tags. For example, in LaTex I want word wrapping for my paragraphs but not for my figure commands (they are always very long and run off the screen).
Or with Javascript, I want the right margin for code to be at, for example 50 columns, but for the comments to be at only 40 columns
This is not builtin
You could probably script something yourself using a devious combination of `formatexpr` and synID(). I suggest you look at the help of the latter first, because it contains inspirational samples:
for id in synstack(line("."), col("."))
echo synIDattr(id, "name")
endfor
taken from :he synstack
The formatexpr is usually set to something like
:set formatexpr=mylang#Format()
thus delegating to a filetype plugin. You could implement the function to use different margins for different syntax contexts.
Bear in mind
the default formatexpr (if absent, formatprg) are probably no good for a source file (in my experience it has the tendency to string together lines as if they were text paragraphs). But then again, you can implement it any which way you want
that syntax highlighting may become out of sync. I'm not sure what happens when the cursor is at, say, 70% of a large document and you issue ggVGgq. It might not update the syntax highlighting all the way (meaning that your formatexpr function would get the 'wrong' synID() values. You get around this by saying something like
:syntax sync fromstart
this again might impact the highlighting performance depending on the size/complexity of the source and highlighting scripts

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