Decode Vim find/replace string that calls a function

Question

I am using the following Vim command line that inserts line numbers to the beginning of lines:

:let i = 1 | %s/^/\='LINE_' . Inc()/g

Inc() is a function that increments the i variable.

This is all working fine. My questions:

1) What does the dot do in the replacement part?:

:let i = 1 | %s/^/\='LINE_' . Inc()/g
                            ^

2) What does the pipe character do? Is there actual piping going on, or is it just syntax?

3) What does the \= do? I think it is used to call the function, but Vim help only shows information for \= as being a quantifier in regex.

4) I have not been able to insert a space after the line number and the first character of the actual line. How can I do this? Anything I place after Inc() in the replacement part is either being ignored or causing an E15 invalid expression error.

I am using Vim 7.3 on Windows 7.

Best way to find help on a Vim topic is CTRL-D. For example type :h \=<C-D> to see all the help tags that contain \=. In this case :s\= is the right one and you can find lots more information there. — glts
– glts, Commented Jan 9, 2014 at 21:18
@glts: +1 THANK YOU! This is an invaluable piece of advice. I was just thinking that the entire time I was grappling with the problem of finding out information about the \= expression, it was present within the application's help file, but I did not know how to access it. Thanks so much. — Sabuncu
– Sabuncu, Commented Jan 9, 2014 at 21:48

Peter Rincker · Accepted Answer · 2014-01-09 21:00:13Z

1

Some explanation:

. expression will concatenate two strings. See :h expr-.
| will separate to ex-commands. See :h :bar
A replacement starting with \= in :s command means the rest of the replacement is to be treated as an vim expression. See :h :s\=
Concatenate a string with a space after the Inc() function call. :let i = 1 | %s/^/\='LINE_' . Inc() . ' '/g

answered Jan 9, 2014 at 21:00

Peter Rincker

45.6k9 gold badges79 silver badges113 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

Sabuncu Over a year ago

I think I was the one who pushed you over 10K! Congratulations.

Peter Rincker Over a year ago

Glad I was able to help you. Cheers!

Collectives™ on Stack Overflow

Decode Vim find/replace string that calls a function

1 Answer 1

2 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

2 Comments

Your Answer

Sign up or log in

Post as a guest

Related