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.
Related
Why can't this line correctly highlight all things between (* and *) as comments in vim?
syn region datsComment start="(\*" end="\*)" contains=datsComment,datsTodo
hi def link datsComment Comment
It does for me (in a fresh buffer without other syntax definitions). You probably have other syntax elements there that prevent a match.
You need to find out which syntax group causes that. :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. If you find other syntax groups obscuring the match, you probably should include them in the contains=datsComment,datsTodo,... part.
Inspired by several posts, like Your syntax highlighter is wrong, Coding in color and A case against syntax highlighting and some others, I decided making a Vim theme that applied some of these concepts would be a good idea.
The thing is I'm not exactly sure how.
From what I can tell, in order to make a Vim theme you need to basically link a color with a syntax identifier or name. And repeat this hundreds or dozens of time in order to have in your lap a theme.
Like for example linking the color #ff0000 (red) and the syntax identifier, or key, Error. As an example. Not sure if that's actually the syntax key.
This would work fine, except that, every syntax that I don't consider important I have to define as just a default foreground value.
And let's say I wanted to add a new syntax keyword, I'd have to do it with ftsyntax and stuff (I believe) and that would be filetype specific etc.
So the first question is:
What would be the best way to give everything a default foreground color and only pick the exceptions to have some colors?
And the second, perhaps more important question is:
How do I syntax highlight a specific piece of text without having to add a syntax rule? For example have a regex that finds any = and highlights them green, without having to add a syntax rule specific for that.
Any help is appreciated. Of course if the approach I'm taking to this is not ideal or sucks I am open to suggestions to alternatives. Thank you. :)
See the example syntax file below:
syn keyword myKeywords We Are Important Keywords
syn match myEquals '='
hi link myKeywords Special
hi link myEquals Operator
This will put We, Are, Important and Keywords into the myKeywords syntax group and = into the myEquals syntax group.
Then we specify how we want to highlight them, by linking it to the Special and Operator highlight groups.
See: :help group-name for a list of the highlight groups and what the colors look like with your color-scheme.
In my color-scheme, Special is Red and Operator is green.
By default, everything else is set to the default foreground color.
I saved this to ~/.vim/syntax/greduan.vim and tested with :set syntax=greduan
Your question touches two domains:
syntax definition
syntax highlighting
Syntax definition, as in Caek's answer, is simple for the first 10 minutes but grows very quickly into a major PITA because it is a core aspect of Vim's architecture with ramifications far beyond syntax highlighting.
Syntax highlighting has its pitfalls but it is a lot simpler than syntax definition.
I think that you can tackle the problem described in those blog posts with syntax highlighting first and, if needed, graduate to syntax definition.
Grab a simple colorscheme like Busybee.
Link all the highlight groups you don't need to Normal while leaving the ones you want to keep:
hi link Foo Normal
What would be the best way to give everything a default foreground
color and only pick the exceptions to have some colors?
What is best depends ... for me the best, because quickest way was clearing unwanted highlighting in ~/.vimrc:
sy on
hi c Constant|hi c Error|hi c PreProc|hi c Special|hi c Statement|hi c Type
hi c Identifier
How do I syntax highlight a specific piece of text without having to
add a syntax rule?
If by syntax rule you mean syntax item, I'd say you cannot have syntax highlighting without defining syntax items.
Spell check in vim is nice enough to not highlight things inside of a math environment when writing LaTeX. This is convenient, but I make some very common typos like "theat" instead of "theta" that would be nice to catch automatically. Is there a way to get the words in the explicit list of 'bad words' to be highlighted regardless of their context?
Note that I still don't want to check whether everything is good within a math environment, just that it is not explicitly bad.
To enable spell checking for a syntax group, you'd have to add contains=#Spell, e.g. for the texStatement group, that would be:
:syn match texStatement "\\\a\+" contains=#Spell
But with that, you'd still have to add all "good" statements to your spell file. If you just want to highlight certain "bad" words, you can define a contained match:
:syn match texBadStatement "theat" containedin=texStatement
And then link to the error or bad spell highlighting:
:hi link texBadStatement SpellBad
Put those commands into ~/.vim/after/syntax/tex.vim to make them persistent.
I'm not a Latex specialist. If the texStatement group is wrong, you need 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.
I'm writing a vim syntax script and I want to be able to make lines matching a certain pattern, say, '^>', "source" or imitate the markdown syntax highlighting.
Is there a way to do this at the syntax script level? Do I need to just copy and paste it in manually and make the proper adjustments? Does this require a modeline on the actual file?
Thanks!
Have a look at :help :syn-include. It allows you to import an existing syntax (like e.g. markdown) into a syntax cluster in your own syntax, and then you can assign syntax regions (if I understand you correctly, that would be a region starting with /^>/ and ending at the end of the line /$/) to it.
Note that success isn't guaranteed; you need some collaboration from the included syntax. (For example, if the markdown syntax anchors its patterns at ^, but now it's included behind the > prefix, it won't match any more.) In the worst case, you have to modify the included syntax or copy it completely into your own syntax.
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.