Reply to message «Re: detecting first and last line of the current paragraph», sent 05:43:54 22 July 2011, Friday by Ben Schmidt:
> Or you could just check whether the search fails or not:
>
> let lastline = search('^\s*$', 'nW')
> let lastline = lastline == -1 ? line('$') : lastline - 1
Failed search returns 0: unlike lists, first line has number 1. Thus you could
just remove ` == -1' as non-failed search() returns non-zero which is taken an
`true'.
> P.S. Since you mentioned that you're learning Vimscript, here is a
> different approach, which is probably the one I would take for starters.
>
> I would think "How would I do this if I were just doing it manually?"
> The answer is that I would highlight the current paragraph by using vip
> then change to visual block mode with Ctrl-v and then use I to add the
> comment leader. I could instruct Vim to do this in Vimscript using a
> one-liner:
>
> exec "normal vip\<C-v>I# \<Esc>"
I avoid using visual mode anywhere because it overrides old visual highlighting
defined by user and moves the cursor. It should be also `normal!' here if you
want to write this in a script.
Original message:
> On 22/07/11 9:56 AM, Jose Caballero wrote:
> > Hi,
> >
> > I am trying to write a function to comment all lines of code in a block.
> > Note the main purpose for this is to educate myself on vim scripting,
> > given I am quite new with it. I am sure there are many other solutions
> > to do it, and much better, but I want to do it in this way to learn.
> >
> > I have written this [1] so far.
> >
> > The idea is to search backwards the first blank line, and then forwards.
> > Once I have all lines that are not blanks, I just add '#' at the
> > beginning of each one. It works unless the block is at the very end of
> > the document, for example. In that case the search for the 'lastline'
> > fails. Same if the block is at the very beginning.
> >
> > Any tip or suggestion to fix that?
>
> You could make the regex match at the end of the document, though I
> think that will probably make your adjustment mess up and omit the last
> line:
>
> let lastline = search('^\s*$\|\%$', 'nW') - 1
>
> Or you could just check whether the search fails or not:
>
> let lastline = search('^\s*$', 'nW')
> let lastline = lastline == -1 ? line('$') : lastline - 1
>
> Just a couple of thoughts to get you started. I haven't tested.
>
> :help expr1
> :help line()
> :help /\%$
>
> Ben.
>
> P.S. Since you mentioned that you're learning Vimscript, here is a
> different approach, which is probably the one I would take for starters.
>
> I would think "How would I do this if I were just doing it manually?"
> The answer is that I would highlight the current paragraph by using vip
> then change to visual block mode with Ctrl-v and then use I to add the
> comment leader. I could instruct Vim to do this in Vimscript using a
> one-liner:
>
> exec "normal vip\<C-v>I# \<Esc>"
>
> :help :normal
> :help :exec
> :help expr-string
> :help <>
> :help CTRL-V
> :help v_b_I
> :
> > [1]
> > function Comment()
> >
> > let firstline = search('^\s*$', 'bnW') + 1
> > let lastline = search('^\s*$', 'nW') - 1
> > for linenum in range(firstline, lastline)
> >
> > let oldline = getline(linenum)
> > let newline = '#'.oldline
> > call setline(linenum, newline)
> >
> > endfor
> >
> > endfunction
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