Mfcttrf

A vim newbie here.

Would like to know an efficient way of converting

self.mat = material
self.epsilon=epsilon
self.x = x

to

self.mat, self.epsilon, self.x = material, epsilon, x

There might be plug-ins that do this particular transformation, or you might be able to use two fairly long :s/// commands to isolate each side.

But personally I find that using Vim's Visual Block feature is the best way to handle column data, which is the main kind of transformation you have here.

You can start by aligning the =s so you really have three columns (the variables to be assigned, the =s and the expressions.) I previously wrote an answer on how to do that using visual block mode.

Once you have that, you can again use visual block mode to cut the right column and paste it into its own lines. Go to the start of material, then use CTRL-V to start visual block mode, then 2j to select the three lines and finally $ to select to the end. Use d or x to cut that text.

Navigate to a blank line (for example, use o at the last line of the file to create a new bla m one and then <Esc> to go back to normal mode.) Then paste with P. You'll have your three expressions in different lines.

Visually select the first two again: CTRL-V, j, $ and add commas. You can use A,<Esc> which will add commas to the end of every line in the visual block selection.

Finally join them with 3J.

With the variable names, first you'll need to clean up the whitespace at the end, together with the =, which you can do with 3:s/ *= *$//. At that point, you can use the same procedure to add commas to the end of the first few lines (except the last one) and join them together. (Also possible is 3:norm f D to jump to the first space and delete til the end of the line, or 3:norm f C, to add a comma already.)

Here all you need to do is insert an = back to the line with the list of variables, and paste back the list of expressions to the end of that.

All done!

It's a bit of work, but it's a really flexible method that you can use in many similar situations, visual block mode is a tool in Vim I definitely recommend that everyone who uses Vim should really learn! It can be really useful for this kind of text transformation.

I'm not sure this is what you want, but you could try these global commands:

g/^self./,/^(self.)@!/-j
g/^self./let l=[]|s/s*=s*(w*)/=add(l, submatch(1))[-1][-1]/g|s/s/, /g|s/$/=' = '.join(l, ', ')

The first command should turn this block:

self.mat = material
self.epsilon=epsilon
self.x = x

into this line:

self.mat = material self.epsilon=epsilon self.x = x

The second command should turn the latter line into:

self.mat, self.epsilon, self.x = material, epsilon, x

Note that it doesn't work if the last line of the buffer starts with self..
In that case, maybe you could add an empty line at the end, before running the commands.

If this is a frequent task, and you don't want to remember these commands, you can wrap them inside a custom command.
As an example:

com! -bar -range=% AssignmentMulti2Single call s:assignment_multi2single(<line1>,<line2>)
fu! s:assignment_multi2single(lnum1,lnum2) abort
 if getline('$') =~# '^self.' | $put='' | endif
 exe a:lnum1 . 'ka'
 exe a:lnum2 . 'kb'
 let range = "'a,'b"
 sil exe range . 'g/^self./,/^(self.)@!/-j'
 sil exe range . 'g/^self./let l=[]|s/s*=s*(w*)/=add(l, submatch(1))[-1][-1]/g|s/s/, /g|s/$/=" = ".join(l, ", ")'
endfu

You can use this AssignmentMulti2Single custom command on an arbitrary range, like :12,34 to target the lines from the address 12 to 34, or like '<,'> to target the last lines which were visually selected.

I haven't tested the code a lot; only on this text file:

self.mat = material
self.epsilon=epsilon
self.x = x

some text

self.one = abc
self.two=def
self.three = ghi

some other text

self.four = jkl
self.five=mno
self.six = pqr

Which :AssignmentMulti2Single turns into:

self.mat, self.epsilon, self.x = material, epsilon, x

some text

self.one, self.two, self.three = abc, def, ghi

some other text

self.four, self.five, self.six = jkl, mno, pqr

So there are probably special cases that it doesn't handle well.

For more information, see:

:h :g
:h :j
:h :s
:h :s=
:h :com
:h :command-bar
:h :command-range
:h <line1>
:h :put
:h :k
:h :silent
:h :exe
:h add()
:h submatch()
:h join()
:h getline()
:h =~#
:h /^
:h /$
:h /(
:h /@!
:h s
:h w