VIM – Toggle Ruby Hash Syntax

Ruby 1.9 introduced a new json style ruby hash syntax. Although we can use this to define static hash objects and puts a limitation on the key we can use, it’s a fairly neat syntax nevertheless. However I work on several projects, both new and old and hence the new syntax is not always readily available.

# Old style hash
hash = { :a => 'test' }

# New style hash
hash = { a: 'test' }

To demonstrate the sheer power of regular expressions & VIM, here’s a tiny snippet that allows you to quickly toggle a ruby hash syntax from one form to other.

function! s:RubyHashSyntaxToggle() range
  if join(getline(a:firstline, a:lastline)) =~# '=>'
    silent! execute a:firstline . ',' . a:lastline . 's/[^{,]*[{,]\?\zs:\([^: ]\+\)\s*=>/\1:/g'
    silent! execute a:firstline . ',' . a:lastline . 's/[^{,]*[{,]\?\zs\([^: ]\+\):/:\1 =>/g'
command! -bar -range RubyHashSyntaxToggle <line1>,<line2>call s:RubyHashSyntaxToggle()
noremap <Leader>rh :RubyHashSyntaxToggle<CR>
comments powered by Disqus