Drastic proposal: rename eruby to rhtml to make way for an HTML free eruby filetype

[Hugh Sasse]

On Fri, 9 Mar 2007, Tim Pope wrote:

> The subject says it all.  The most common use of eruby is filling out
> HTML templates, but this is by no means the only use.  I think it

No, see the book "Code Generation in Action" for example.  

http://www.codegeneration.net/tiki-index.php?page=GenerationBooks

> would be a good idea to have an rhtml filetype for html templates, and
> an eruby filetype for everything else.  There is precedent for this
> elsewhere:  Vim has a django filetype for Django templates and

OK, but I've not looked at that yet, so my comments aren't based on
deep knowledge...

> apparently will be getting a separate djangohtml filetype.
> 
> transition until Vim 7.1 draws nearer.  At this point, I'm looking for
> objections other than "this would be hard to do."  If there were

The difficulty I see is that when you mix syntaxes you have to pull
in the right syntax groups, and there isn't a *simple* way to do thig
in vim.  With lots of help from Doug and others I have, for example
in my .vimrc:

function RubyMetaMake()
  :unlet! b:current_syntax
  :syntax include @MAKESTUFF ~/.vimrc_include_make_syn
  :syntax region rubyC1 matchgroup=String start=+%Q{+ end=+}+ keepend contains=@CSTUFF
  :syntax region rubyMakeString start=+\%(\%(class\s*\|\%(\.\|::\)\)\_s*\)\@<!<<-MAKESTRING\ze+hs=s+3    matchgroup=rubyStringDelimiter end=+^\s*\zsMAKESTRING$+ contains=rubyHeredocStart, at rubyStringSpecial, at MAKESTUFF fold keepend
endfunction

" To MetaProgram C using Ruby
function RubyMetaC1()
  :unlet! b:current_syntax
  :syntax include @CSTUFF ~/.vimrc_include_c_syn
  :syntax region rubyC1 matchgroup=String start=+%Q{+ end=+}+ keepend contains=@CSTUFF
  :syntax region rubyC2 matchgroup=String start=+%Q(+ end=+)+ keepend contains=@CSTUFF
  :syntax region rubyC3 matchgroup=String start=+%Q<+ end=+>+ keepend contains=@CSTUFF
  :syntax region rubyC3 matchgroup=String start=+%Q£+ end=+£+ keepend contains=@CSTUFF
"  :syntax on
endfunction
function RubyMetaC2()
  unlet b:current_syntax
  syn include @cTop syntax/c.vim
  let b:current_syntax = "ruby"

  syn region rubyCString start=+\%(\%(class\s*\|\%(\.\|::\)\)\_s*\)\@<!<<CSTRING\ze+hs=s+2    matchgroup=rubyStringDelimiter end=+^CSTRING$+ contains=rubyHeredocStart, at rubyStringSpecial, at cTop fold keepend
  syn region rubyCString start=+\%(\%(class\s*\|\%(\.\|::\)\)\_s*\)\@<!<<"CSTRING"\ze+hs=s+2  matchgroup=rubyStringDelimiter end=+^CSTRING$+ contains=rubyHeredocStart, at rubyStringSpecial, at cTop fold keepend
  syn region rubyCString start=+\%(\%(class\s*\|\%(\.\|::\)\)\_s*\)\@<!<<'CSTRING'\ze+hs=s+2  matchgroup=rubyStringDelimiter end=+^CSTRING$+ contains=rubyHeredocStart, at cTop		      fold keepend
  syn region rubyCString start=+\%(\%(class\s*\|\%(\.\|::\)\)\_s*\)\@<!<<`CSTRING`\ze+hs=s+2  matchgroup=rubyStringDelimiter end=+^CSTRING$+ contains=rubyHeredocStart, at rubyStringSpecial, at cTop fold keepend

  syn region rubyCString start=+\%(\%(class\s*\|\%(\.\|::\)\)\_s*\)\@<!<<-CSTRING\ze+hs=s+3    matchgroup=rubyStringDelimiter end=+^\s*\zsCSTRING$+ contains=rubyHeredocStart, at rubyStringSpecial, at cTop fold keepend
  syn region rubyCString start=+\%(\%(class\s*\|\%(\.\|::\)\)\_s*\)\@<!<<-"CSTRING"\ze+hs=s+3  matchgroup=rubyStringDelimiter end=+^\s*\zsCSTRING$+ contains=rubyHeredocStart, at rubyStringSpecial, at cTop fold keepend
  syn region rubyCString start=+\%(\%(class\s*\|\%(\.\|::\)\)\_s*\)\@<!<<-'CSTRING'\ze+hs=s+3  matchgroup=rubyStringDelimiter end=+^\s*\zsCSTRING$+ contains=rubyHeredocStart, at cTop		     fold keepend
  syn region rubyCString start=+\%(\%(class\s*\|\%(\.\|::\)\)\_s*\)\@<!<<-`CSTRING`\ze+hs=s+3  matchgroup=rubyStringDelimiter end=+^\s*\zsCSTRING$+ contains=rubyHeredocStart, at rubyStringSpecial, at cTop fold keepend

  syn cluster cCommentGroup contains=cTodo,rubyInterpolation
endfunction

There are 2 ways of doing it in there.
Well, I don't call that light reading, anyway. :-)
My point is that the OTHER syntax, outside of the ruby, is nontrivial
to cnnect to, and I expect that having a syntax file for ERB will 
raise the expectation that it is trivial to get the highlighting right
for that as well at the same time.

> no technical or backwards compatibility restrictions, and such a
> change could be made with zero side-effects, would anybody disagree
> with such a change?
> 
> An alternative to this is to have a new filetype for eruby files
> without HTML.  Something like plaineruby or erubytext.  This would

Is the extension .erb already taken?

> work but it makes me cringe, much like the tex filetype being LaTeX

Assuming that
:filetype detect 
is "indistinguishable from magic", could it tell the files apart by
the presence of /<%[#=].*?%>/ ?

> and the plaintex filetype being TeX.  I'd like to make my proposed
> change while Vim support for eruby is still young and evolving.
> 
> Once again, I'm looking for idealistic objections at this point rather
> than practical ones.  Does anyone object to the idea of two filetypes,

Drat! :-)  I've answered the wrong question.  Hope soemthing in here
is of use...  In principle I'm in favour of encouraging this use of
eruby, mainly because I keep forgetting about it, and doing code generation
the hard way.  Hence all that sfuff in my vimrc.

> or of my suggested naming scheme?
> 
> Cheers,
> Tim

        Hugh