Vim syntax highlighting: overlapping regex - vim

I try to add some syntax highlighting for javascript to vim, but I keep running into one problem: when characters are already highlighted, they seem to be completely ignored by all other regular expressions.
For example, I tried to add syntax highlighting for the argument list of a function. While creating the right rexex I disabled the syntax highlighting for the function keyword, such that it was easier to see what my regex did. I ended up with the following (working) regex:
syn match javaScriptArguments "[(=\:\s,]function.\{-}(\zs.\{-}\ze)"
However, as soon as I enabled the highlighting for the function keyword again, this line doesn't work anymore. It seems that vim simply excludes everything which is already highlighted, and thus it won't find any matches for the regex above, even though it won't result in characters being highlighted twice.
How can I solve/work around this problem?

Syntax definitions must be contained for them to match inside other syntax items. Find all the gruesome details at :help syn-contains.
In your case, you're relying on a look-before of the "function" keyword via \zs. In my experience, that's bound to cause problems, but may turn out to be unneccessary once you use contained. In general, it is difficult to extend an existing syntax definition without modifying the original script (which I suppose is what you're intending to do). Have a look at :help :syn-containedin and :help :syn-nextgroup.

Related

Why does this regular expression not work in Vim syntax highlighting?

I am attempting to create my own Python syntax highlighting file for Vim.
I'm trying to highlight the class inheritance object and the regex I've created
works in various regex testers, but doesn;t work in Vim. I've read that Vim's regex is close to Perl style
so that is what I've been using.
I'm trying to highlight the word 'Subscribers' in the following text:
class Divisions(Subscribers):
The regex I've composed is:
(?!:class\s\w+)(?<=\()\w+(?=\):)
I'll be honest here, I stumbled into this while I was struggling to make a negative lookbehind work with quantifiers,
which I now understand isn't possible. I was experimenting with the non-capturing group (?:class\s\w+) and accidentally
inserted the exclamation mark which 'magically' solved the problem. At least in the multiple regex testers I was using.
Just for clarity, then follows a look behind (?<=() to caputre but not include the '('
and then a look ahead after the word (?=):) to capture but not include the closing '):'
I've added it to my Vim syntax file as:
syn match pythonClassInherit "(?!:class\s\w+)(?<=\()\w+(?=\):)"
Is this a valid regular expression in Vim? If not, can anybody offer a working solution for Vim?
EDIT: I realized that I've had overcomplicated the issue; you just need a right Vim regex. Try
syntax match pythonClassInherit "\%(class\s\+\h\w*\s*(\s*\)\#<=\h\w*\%(\s*):\)\#="
highlight link pythonClassInherit pythonImport
Then you'll see the result:
You may replace pythonImport by another predefined highlight group.
For highlighting, I found https://learnvimscriptthehardway.stevelosh.com/ (highlighting starts from Chap. 45) helpful. As for regex, romainl's suggestion is awesome.
My first attempt was to use regex \zs. This, unlike \#<=, requires that the syntax group cover the part that comes before \zs, which cannot be satisfied because some other groups have already occupied that part. This led me a complicated solution, by overriding the default highlight groups to include a new group (for Subscribers). But it turns out we really don't have to.
If interested, see Vim syntax file not matching with \zs.
Online regular expression playgrounds don't support Vim's syntax so using them is pointless, here.
See vimregex.com for an overview, :help usr_27 for a gentle tutorial, :help pattern for the definitive reference, and :help perl-patterns for the differences between the Vim syntax and the Perl syntax.

Color highlight function calls in VIM

Does anyone know a way to color highlight function calls in Vim?
I know that some plugins could do something like that by keeping record of tags, but with what I've found online, I could not figure out how to make it work.
I've tried using easy tags (which, by the way, doesn't seem to be maintained anymore) and gutentags, but to be quite honest, I haven't come much close to make any of them to work.
On the other hand, I imagine that it would be quite simple to implement a script to highlight anything that lies between a dot and a left parentheses or a blank space and a left parentheses (as in .anyCodeAtAll(), anotherCode()), but I have no idea how to do it. It would be a incomplete solution of course, but it would be good enough for my purposes at the moment.
Does anyone know how to make that work?
I have something like that in my configuration, but it's quite language specific. For example for Golang, I have a ~/.vim/after/go.vim which contains:
syntax match goCustomParen "(" contains=cParen
syntax match goCustomFuncDef "func\s\+\w\+\s*(" contains=goDeclaration,goCustomParen
" Exclude import as function name, for multi-line imports
syntax match goCustomFunc "import\s\+(\|\(\w\+\s*\)(" contains=goCustomParen,goImport
syntax match goCustomScope "\."
syntax match goCustomAttribute "\.\w\+" contains=goCustomScope
syntax match goCustomMethod "\.\w\+\s*(" contains=goCustomScope,goCustomParen
highlight def link goCustomMethod Function
highlight def link goCustomAttribute Identifier
highlight goCustomFuncDef ctermfg=13
highlight goCustomFunc ctermfg=43
highlight goCustomAttribute ctermfg=247
highlight goCustomMethod ctermfg=33
And for Python, I have a ~/.vim/after/python.vim:
syntax match pyCustomParen "(" contains=cParen
syntax match pyCustomFunc "\w\+\s*(" contains=pyCustomParen
syntax match pyCustomScope "\."
syntax match pyCustomAttribute "\.\w\+" contains=pyCustomScope
syntax match pyCustomMethod "\.\w\+\s*(" contains=pyCustomScope,pyCustomParen
highlight def link pyCustomFunc Function
highlight def link pyCustomMethod Function
highlight def link pyCustomAttribute Identifier
highlight pyCustomFunc ctermfg=43
highlight pyCustomAttribute ctermfg=247
highlight pyCustomMethod ctermfg=33
In each case, the first block defines what is a function, a method, an attribute, and so on, the second block link these custom definition to the generic classes "Function, Identifier..." and the 3rd block defines the colors.
The files need to be in the after directory to be executed after the colorscheme and highlights definitions.
Here's a side by side comparison of with and without these settings (look on the last 3 lines):
Unless someone has a better solution, you could adapt the above for the language you need it.
It might be that you have not installed your plug-in correctly.
Try following these steps (or retrace your steps) and see if it works / missed any steps out:
cd ~ Go to home directory.
vim .vimrc open .vimrc
Insert:
call plug#begin()
Plug 'xolox/vim-easytags'
call plug#end()
easytags#Options states easytags should work out of the box, but you could add option here in the
.vimrc file now or later,
e.g. put:
let g:easytags_syntax_keyword = 'always'
afer the call plug block.
Anyway.
:wq write quit the .vimrc
source ~/.vimrc unsure if required as will do later
vim test.js open vim with test.whatever language you know.
:PlugInstall in vim
Here might take a bit of time.
Then :q out of that window.
:source ~/.vimrc this is needed
Then test out to see if you have syntax highlighting.
I'm pretty sure this is along the right lines. Might be misspelled plugin name.

problem in jumping to system verilog macros `define in VIM using ctags

I checked following things, tags file path is set properly.
the macro tag i am looking for exist in the tags file. task/function/parameters etc works without hiccups. i have problem only with regex.
the expression present in ctags file are
1. --regex-SystemVerilog=/^\s*`define\b\s*(\w+)/`\1/d,define/
2. --regex-systemverilog=/^[ \t]*`define[ \t]*([a-zA-Z_0-9]+)/`\1/d,define/
both the options does not work.
When :tag `altuvm_test_arg works, but the corresponding CTRL-] key doesn't, this often is caused by incompatible 'iskeyword' definitions, so that actually gets passed to :tag is altuvm_test_arg (without the leading backtick).
You can check the scope of keyword matching (when on such a tag) with the * command, which highlights the same keyword under the cursor. If backticks are excluded, try adding the backtick to the range of keyword characters:
:setlocal iskeyword+=`
If this helps (and doesn't break things like syntax highlighting, or annoys you with the changed navigation of commands like w and e), you can make that setting permanent for verilog filetypes put putting it in ~/.vim/after/ftplugin/verilog.vim.

How to color function call in Vim syntax highlighting

I'm new to Vim and curious how to highlight a function call after the function has been defined. As an example, in the SublimeText version, totalForArray is green when it is defined, as well as when it is called on line 12. This is what my Vim looks like imgur.com/q2WMQ4d, and I'm wondering how to make totalForArray highlighted when it's called.
An improvement on Vitor's regex matching.
This will highlight nested function calls while respecting highlighting for keywords like while, if, for, etc... and also allows for whitespace between function name and parenthesis
e.g. myFunction (int argc) { ... }
syn match dFunction "\zs\(\k\w*\)*\s*\ze("
hi link dFunction Function
Vim's syntax parsing usually only colors the function definition, because that one is easy to locate with a regular expression. For function calls, it would have to maintain a list of detected functions.
There are plugins that extend syntax highlighting with such a list, usually taken from the tags database. For example, the easytags.vim plugin performs automatic tags updates and can highlight those via the :HighlightTags command.
As a simpler alternative to what was proposed by #Ingo, you can also define a syntax to match any keyword that is directly followed by a parentheses:
syn match jsFunction "\<\k\+\ze("
hi link jsFunction Function
Searching in github I was also able to find the vim-javascript plugin, which appears to have various extensions to the default Javascript syntax included in Vim. In particular, it contains the following syntax definition:
syntax match jsFuncCall /\k\+\%(\s*(\)\#=/
This will implement the same syntax highlight I described before, but by using this plugin you might also benefit from other improvements that are included in it.

Vim recipe for a minor syntax highlighting extension

I want to leave my system's Python syntax highlighting mostly intact, but I have a specific pattern I'd like to highlight for an idiom I use a lot. How can I add additional highlighting instructions on top of the existing highlighting done by vim?
(Apologies if this has already been asked. All the vim syntax highlighting questions I found seemed to involve writing a new syntax highlighting from scratch.)
Put your additional :syntax commands into ~/.vim/after/syntax/python.vim, and they will be automatically executed after the original syntax script.
It's easy to highlight stuff that so far isn't parsed at all.
For elements already parsed / hightlighted, you need to find out by which syntax group (e.g. pythonFunction), and add a containedin=pythonFunction clause to your :syntax commands. Without that, the original matching will obscure yours. To find out which syntax group causes the highlighting. :syn list shows all active groups, but it's easier when you install the SyntaxAttr.vim - Show syntax highlighting attributes of character under cursor plugin.
Introducing highlighting across (larger) elements that have multiple existing syntax groups is difficult, as your match will obscure the original ones, and that may break the entire parsing. You need to carefully examine the existing nested element structure, and try to fit in yours, again via contains= and containedin= clauses. Depending on the actual situation, that can be difficult.
For the actual syntax definitions, see the help starting at :h :syn-keyword. Basically, there are simple keyword definitions, regular expression matches, and regions defined by start and end patterns.

Resources