[Bug]w in cw is same as ce

[icyhat]

w in cw is same as ce
When w combine with c, cw behaves same as ce.

They both delete from current cursor to end of current word and insert.

But cw should delete from current cursor to where until next word which contain the blanks between it and next word.

To Reproduce

alpha text:         hello world vim
target word:              world
de:                 hello  vim
dw:                 hello vim
ce:                 hello  vim
cw:                 hello  vim

Expected behavior
cw has two parts, delete and insert. its deletion should be like dw which delete until next word, including blanks.
Environment

• Vim version [version 8.1.320]
• OS: [Ubuntu 19.04]
• Terminal: [GNOME Terminal)

[tonymec]

This is documented (under :help WORD):

Special case: "cw" and "cW" are treated like "ce" and "cE" if the cursor is
on a non-blank.  This is because "cw" is interpreted as change-word, and a
word does not include the following white space.

[icyhat]

This is documented (under :help WORD):

Special case: "cw" and "cW" are treated like "ce" and "cE" if the cursor is
on a non-blank.  This is because "cw" is interpreted as change-word, and a
word does not include the following white space.

Thanks. You got a wide range of knowledge.

but since cw could treat as ce, then why the dw is not treated as de due to keeping consistency.

Or, can we exchange w and e as if e is actually end of the word with blanks while w is end of the word, because w is interpreted as word, and a word does not include the following white space.

[chrisbra]

It's actually a strange vi behaviour:

https://github.com/vim/vim/blob/master/src/normal.c#L8648-L8656

Some time ago I made a patch (and I think Neovim merged that one:
neovim/neovim#6235 and https://github.com/chrisbra/vim-mq-patches/blob/master/cpo_changeword

[icyhat]

It's actually a strange vi behaviour:

https://github.com/vim/vim/blob/master/src/normal.c#L8648-L8656

Some time ago I made a patch (and I think Neovim merged that one:
neovim/neovim#6235 and https://github.com/chrisbra/vim-mq-patches/blob/master/cpo_changeword

I wonder is there a flag that I can easily turn on from different platforms to use corrected version of vim while we can keep default in old vim for compatibility?Why should we keep the garbage in the vim and carry on?

[tonymec]

There is a 'compatible' boolean option, and also a related set-of-one-letter-flags 'cpoptions' option, which allow disabling those legacy-vi established behaviours which Bram regards as bugs. 'compatible' is nowadays usually off except if you invoke Vim as 'vi' or with the -C command-line switch.

But in general, Bram regards backward compatibility as extremely important, and IMHO rightly so: backward compatibility goes hand in hand with the principle of least surprise, or IOW, an application cannot be relied on if you cannot count on using it tomorrow like you used it yesterday.

[icyhat]

There is a 'compatible' boolean option, and also a related set-of-one-letter-flags 'cpoptions' option, which allow disabling those legacy-vi established behaviours which Bram regards as bugs. 'compatible' is nowadays usually off except if you invoke Vim as 'vi' or with the -C command-line switch.

But in general, Bram regards backward compatibility as extremely important, and IMHO rightly so: backward compatibility goes hand in hand with the principle of least surprise, or IOW, an application cannot be relied on if you cannot count on using it tomorrow like you used it yesterday.

Thanks your kindness.

I learned a lot

1. use :help cw to search whether there is a solution.
2. use :help cpoptions to check a list of compatible issues.

I checked cpoptions, there is no flag for this bug, but the help manual did give us a solution, :map cw dwi.

As we know that cpoptions is off by default, the only question is that when can we have a flag to enable all better and consistent features while we remain compatibility by default which can be relied on from past to now.

Thanks again, you guys help me so much information.

[icyhat]

Hi there, again.

Since :map cw dwi doesn't work when consistent with ce on the last word of line, which new char waiting for INSERT, I'v turn to use Neovim with single set set cpoptions-=_.

I think compatibility do matters, but self-renewing ability also matters.

Softwares should work as compatibility pattern by default while give a possibility for users to turn on all better and consistent features. Anyway keep a garbage is reasonable due to lacking of time or money or historical issues, but how can we reject growing?

[Roy-Orbison]

@chrisbra can you merge a version of your cpo_changeword patch in a way that doesn't break backwards compatibility? E.g. keep the name z, but omit it from #define CPO_VIM.

I've seen several workarounds, like this one, including the suggested mapping in the help docs, but none work like native support would. The help suggestion can only be multiplied like 2cw instead of the usual c2w, and suffers the same inconsistency at the ends of the lines. There are plenty of people that would appreciate real support for this.

[chrisbra]

Alright, let me create a new PR for this one then. It needs a test and I must check how if this still applies.

[chrisbra]

I made #15263 but Note: change change to CPO_VIM is required, exactly to stay backwards compatible.

[Roy-Orbison]

Much appreciated, @chrisbra.