extract-css-var.vim

" Extracts a CSS var
"
" Setup:
"   Load this in your VIM: `source extract-css-var.vim`
"
" Usage:
"   Place cursor on any line with CSS. ie "color: red;"
"   Call the function (ideally with a key mapping): `call ExtractCSSVar()`
"   You'll be prompted to enter a name for the var, then hit Enter (defaults to the current property name)
"   It will update the current line, and place the var value, ie `--var-name: original-value` inside the default register (so you can paste it)
function! ExtractCSSVar()
  let line = getline(".")
  let trimmed = Trim(line)

  " error if not a CSS attribute expression
  if stridx(trimmed, ":") < 0
    echohl ErrorMsg | echom "Expected CSS expression `attribute: value`" | echohl None
    return
  endif

  let stripped = ChompSemi(l:trimmed)
  let parts = split(stripped, ':')
  let property = Trim(parts[0])
  let value = Trim(parts[1])
  let varName = "--" . input("var name: ", property)
  let lineNo = line(".")
  let whitespace = LeadingWhitespace(l:line)

  " replace current line, preserving whitespace
  call setline(lineNo, whitespace . property . ": var(" . varName . ");")

  " put in register
  let @" = whitespace . varName . ": " . value . ";"
endfunction

" returns leading whitespace
function! LeadingWhitespace(input)
  return substitute(a:input, '^\(\s*\).*', '\1', '')
endfunction

" remove semicolon
function! ChompSemi(input)
  return substitute(a:input, '^\(.*\);$', '\1', '')
endfunction

" remove whitespace from text
function! Trim(input)
  return substitute(a:input, '^\s*\(.\{-}\)\s*$', '\1', '')
endfunction