When running tools such as formatters and linting tools with "auto-correction" options, it can be that the input and output for a Rule are the same file; for example:
"//*.hs" %> \out ->
cmd_ "ormolu" "-m" "inplace" out
-- OR
batch 10 ("//*.hs" %>)
( \out -> do
cmd_ "ormolu" "-m" "inplace" out
pure out
)
(cmd_ "hlint")
This seems to work "correctly" (the rule is re-run if the source file is needed and has changed), but we're unsure if this is a happy coincidence or shake working as designed - especially when we start thinking about cached results from shakeShare or in the future Cloud Shake. Is this the best way to handle this type of rule, or is there something better?
There is no principled way to generate a rule that replaces a source file in Shake. Given a source code formatter, anything else isn't very usfeul. Shake makes the assumption that inputs don't change while the compilation is ongoing. It's likely that passing --lint will lead to a lint error and that it would be incompatible with Cloud Shake. The official advice would be to make such changes in a separate non-Shake pass before you call shake.
However, if it works for you, and is useful, I wouldn't overly worry. The pattern has tests in Shake, it's something plenty of people do. You can turn off Cloud caching on a per file basis with historyDisable.
Related
This question may be a little off topic. But I was wondering if there was a way for me to look at the descriptions of C functions using vim or neovim. Is it possible to look at their documentations by doing something like :help? This would really be helpful since I wouldn't need to lookup to my browser everytime.
I am unclear about these things:
Can :help be my friend here ?
Can I use LSPs to do something like this ?
I am using latest Neovim inside Ubunutu 20.04 in WSL. Is this helpful somehow ?
By pressing K, the keyword under the cursor is looked up using a configured keyword lookup program, the default being man. This works pretty much out of the box for the C standard library.
For C++, you might want to look at something like cppman.
Well yes, you can get the description of C functions by using a LSP (language server plugin)! Here is an image of me using clangd as my LSP:
You'd "just" need to install the LSP and start it. I don't know how familiar you're with neovim, but just in case if you don't know how to install a plugin or to be more specifique: If you don't know how you can install a LSP server, then you can do the following:
There're plenty videos how to set up a LSP-Server for your language. Here's an example.
If you don't want to set up on your own, you can pick up one of the preconfigured neovim setups (some of my friends are recommending lunarvim)
But yeah, that's it. If you have any further questions feel free to ask them in the comments.
Happy vimming c(^-^)c
Let's explain how "K" command works in more detail.
You can run external commands by prefixing them with :! command. So running man tool is as easy as
:!man <C-R><C-W>
Here <C-R><C-W> is a special key combination used to put word under cursor from text buffer down to command line.
Same for showing Vim's built-in help page
:help <C-R><C-W>
As it feels tedious to type that, Vim also defines K Normal mode command that does pretty much the same thing. Except the tool name is taken from value of an option named "keywordprg".
So doing set keywordprg=man (default for *nix systems) makes K to invoke !man tool; while set keywordprg=:help is for bultin help.
Also, the option :h 'keywordprg' is made global or local-to-buffer, so any Vim buffer is able to overwrite global setting. For example, this is already done by standard runtime for "vim" and "help" buffers, so they call ":help" instead of "man".
The problem with :!man command is that it shows "black console". It'd be nice if we could capture man's output and open it inside Vim just like a builtin help page. Then we could also apply some pretty highlighting, assign key macros and all such. This is a pretty common trick and it is already done by a standard plugin shipped with Vim/Neovim.
A command that the plugin provides is called :Man, so you can open :Man man instead of :!man man, for example. The plugin is preactivated in Neovim; for Vim you still need to source one file manually. So to make use of this plugin you'll need something like this
set keywordprg=:Man
if !has("nvim")
source $VIMRUNTIME/ftplugin/man.vim
endif
The previous answer recommending cppman is the way to go. There is no need to install a bulky language server just for the purpose of having the hover functionality. However, make sure you're caching the man pages via cppman -c. Otherwise, there will be a noticeable delay since cppman is fetching the page from cppreference.com on the fly.
If you like popups for displaying documentation, convert the uncompressed man pages (groff -t -e -mandoc -Tascii <man-page> | col -bx), and set keywordprg to your own wrapper to search for keywords according to your needs.
We would like to run a Shake build while assuming some target is built, e.g. something like
./Build.hs --dont-rebuild my-target
Reading the docs it seems there should be a way to do that but I can't find it.
The ShakeOptions setting you are looking for is shakeRebuild=[(RebuildLater,"my-target")]. This setting causes Shake to not rebuild my-target in this run. From the documentation of RebuildLater:
This assumption is unsafe, and may lead to incorrect build results in this run. Assume these files are clean in this run, but test them normally in future runs.
This setting can be applied using the command line --skip=my-target. A few caveats:
my-target won't rebuild in this run, by things it depends on might, if they need to.
If you next run without skipping my-target, it will rebuild if it needs to (the --skip is not sticky).
I am building a shake based build system for a large Ruby (+ other things) code base, but I am struggling to deal with Ruby commands that expect to be passed a list of files to "build".
Take Rubocop (a linting tool). I can see three options:
need all Ruby files individually; if they change, run rubocop against the individual file that changed for each file that changed (very slow on first build or if many ruby files change because rubocop has a large start up time)
need all Ruby files; if any change, run rubocop against all the ruby files (very slow if only one or two files have changed because rubocop is slow to work out if a file has changed or not)
need all Ruby files; if any change, pass rubocop the list of changed dependencies as detected by Shake
The first two rules are trivial to build in shake, but my problem is I cannot work out how to represent this last case as a shake rule. Can anyone help?
There are two approaches to take with Shake, using batch or needHasChanged. For your situation I'm assuming rubocop just errors out if there are lint violations, so a standard one-at-a-time rule would be:
"*.rb-lint" %> \out -> do
need [out -<.> "rb"]
cmd_ "rubocop" (out -<.> "rb")
writeFile' out ""
Use batch
The function batch describes itself as:
Useful when a command has a high startup cost - e.g. apt-get install foo bar baz is a lot cheaper than three separate calls to apt-get install.
And the code would be roughly:
batch 3 ("*.rb-lint-errors" %>)
(\out -> do need [out -<.> "rb"]; return out) $
(\outs -> do cmd_ "rubocop" [out -<.> "rb" | out <- outs]
mapM_ (flip writeFile' "") pits)
Use needHasChanged
The function needHasChanged describes itself as:
Like need but returns a list of rebuilt dependencies since the calling rule last built successfully.
So you would write:
"stamp.lint" *> \out -> do
changed <- needHasChanged listOfAllRubyFiles
cmd_ "rubocop" changed
writeFile' out ""
Comparison
The advantage of batch is that it is able to run multiple batches in parallel, and you can set a cap on how much to batch. In contrast needHasChanged is simpler but is very operational. For many problems, both are reasonable solutions. Both these functions are relatively recent additions to Shake, so make sure you are using 0.17.2 or later, to ensure it has all the necessary bug fixes.
On OS X, I generated a set of ctags for the system includes using the following command:
ctags -f c -h ".h" -R --c-kinds=+p --fields=+iaS --extra=+q /usr/include
This was run inside of a ~/.vim/ctags/ directory, where I put all of the ctags I generate for system-wide header files (I also have stuff for ROS and CPP that I load conditionally, but that's neither here nor there).
Anyway. The ctags file is set correctly in my .vimrc, and vim can definitely see the ctags, but for some reason the autocomplete popup will only display results from #included header files if I write out the entire symbol and then start backspacing. As an example, if I #include <string.h> in a project, and then I want to call strlen(), and I start to type str in to the active vim buffer, I will only get results for symbols that are currently in the vim buffer. But, if I type out strlen and then start backspacing one or two characters and hit <C-n>, the popup menu will be populated with matches from any other included header files.
EDIT: Turns out, if I just hit "s" then <C-n>, it works as well. So the problem seems to be that it only works if the popup menu is launched manually. Which makes me think that it's a plugin problem (see below)
Additional information:
completeopt is set to completeopt=menuone,menu,preview,longest
I have OmniCppComplete, which I suppose could be interfering with the behavior. It is currently not being conditionally loaded for C++ files only. If you want me to edit and post my OmniCppComplete settings from my .vimrc, just ask.
I also have AutoComplPop installed, but I haven't done anything to configure it, so it's running with its default settings. Haven't really researched the plugin, so no idea if some of it's behavior could be interfering with the results.
I have AutoTag and TagBar installed, but those should only be fiddling with the current directory's local tagfile.
I'm honestly pretty new to Vim, and I just have no idea where to start debugging this issue, whether it be with a random plugin or with my .vimrc settings.
Vim has many specific completion mechanisms.
<C-n> and <C-p> use many sources defined by the complete option. By default, they will provide completion using the current and all loaded and unloaded buffers, tags and included files. While you can usually get quite useful suggestions with these, it is a bit of a "catch-all" solution: it is not reliable at all if you work on reasonably large projects.
<C-x><C-]> uses only tags so it may be a little more useful to you.
And there are many more, see :h ins-completion.
Omni completion is smarter: it typically runs a custom filetype-specific script that tries hard to provide meaningful completion. It is triggered by <C-x><C-o> and you can read about it in :h ft-c-omni. Omni completion is often a better choice when working with code.
Because you have two overlaping "auto"-completion plugins it's hard to say what completion mechanism is at work. You should disable those plugins and play around with the different completion mechanisms available to you.
I have not mastered this yet, but I do think the following observation may be of help.
Vim's default auto complete which can be quite noisy, often gets in the way of what you call with <C-x><C-o>. Specifically, I found myself calling up my tags based completions with <C-x><C-o> only to have them replaced with continued typing with Vim's default suggestions using my open buffers.
The suggestion of shutting off one of the plugins makes sense. In my case the key was how to shut down Vim's default behavior. I have seen several people (and to which I now include myself), set the length of the expression to a high number before triggering Vim's default. For me that is:
let g:deoplete#auto_complete_start_length = 99
... this way you eliminate the default layer of completions that comes and goes regardless of the commands you intended to inform your work.
This still feels like a hack but it helps keep my work focused on the tag-based completions.
FYI: I use NVIM on a Mac.
I've written a built-in for bash which modifies the 'cd' command, a requirement for my software. Is there a way to actually distribute a loadable independently of bash itself? I'd ideally like to distribute just a drop in "additional feature" because I know people can be put off by patching and compiling their shell from source code.
I want to time how long a user is in a directory so I can determine where they want to be. It's this functionality: http://github.com/joelthelion/autojump/tree/master rewritten as a bash builtin, for performance issues. This implementation uses $PROMPT_COMMAND to work but I wanted something integrated.
It is unclear what you have modified but in any case, bash (like at least ksh93 which IIRC introduced the concept and zsh) supports, using the enable -f file name syntax, loading built-in functions as external dynamically loaded modules.
These modules being plain files can certainly be distributed independently, as long as you make sure they are compatible with the target version/architecture. This was already true 5 years ago when you asked this question.
One issue in your case is there seems to be no documented way to overload a internal built-in like cd by a dynamically loaded one while keeping the ability to access the former.
A simple workaround would be to implement your customized cd with a different name, say mycd, like this:
int mycd_builtin(list)
WORD_LIST *list;
{
int rv;
rv=cd_builtin(list);
if(rv == EXECUTION_SUCCESS) {
char wd[PATH_MAX+1];
getcwd(wd,sizeof(wd));
// do your custom stuff knowing the new working directory
...
}
return (rv);
}
then to use an alias, or better, a shell function for your customized version to be used instead of the regular one:
cd() {
mycd "$#"
}
As long as your customization doesn't affect the behavior of the standard command and thus doesn't risk breaking scripts using it, there is nothing wrong in your approach.
Changing the built-in cd is a support nightmare for any admin and unwelcome to foreign users. What is wrong with naming it 'smart-cd' and letting the USER decide if they want the functionality by including it in their .bashrc or .profile? Then they can setup things however they want.
Also, using how long you've been in a directory is a pretty poor indication of preference. How would you distinguish between idling (a forgotten shell hanging in /tmp overnight), long-running scripts (nightly cron jobs), and actual activity.
There are a multitude of other methods for creating shortcuts to favorite directories: aliases, softlinks, $VARIABLES, scripts. It is arrogant of you to assume that your usage patterns will be welcomed by other users of your system.