This Vim plugin provides text objects for chain members: im and am. It depends on the textobj-user plugin.

There is no established terminology, so I made one up. You know method chaining as in foo.bar().baz(), right? A member chain is an abstraction of that, because such a chain could also consist of attributes, fields, properties, however you want to call variables of a class. A chain member then is just a member in a member chain. Easy. :)

Why not just use targets.vim's i. and a.? Let me show a few examples, in the fantastic notation of that plugin.

For am, the first chain member includes the dot to its right:

cursor position │ ..... buffer line │ first.second.third selection │ └ am ┘ 

..., all following members the one to their left:

 ....... first.second.third └ am ─┘ 

im does not include the dot:

 ....... first.second.third └ im ┘ 

Method calls can be selected outside their argument list:

 ........ . first.second(arg1, arg2).third └────── am ───────┘ 

Dots and other special characters inside the argument list are skipped:

 ........ . first.second(arg1.var, foo()).third └───────── am ─────────┘ 

Inside the argument list, the outside is ignored:

 ...... first.second(foobar.var, arg2).third └ am ─┘ 

Chars and string contents are ignored:

 ........ . first.second(") ", '.').third └────── am ──────┘ 

Type parameters are no problem, either:

 ........ ... first.second<Type.InnerType>().third └────────── am ─────────┘ 

..., nor are (multi-dimensional) arrays:

 ........ .. . first.second[foo.index][j].third └─────── am ────────┘ 

... and curried function calls:

 ........ .. . first.second(foo.bar)(foobar.baz).third └─────────── am ───────────┘ 

More than one member can be selected:

..... first.second.third └── 2im ───┘ 

..., or the next or last one:

..... first.second.third └ anm ┘ ...... first.second.third └ alm ┘ 

..., which can be combined with a count:

..... first.second.third └── 2anm ───┘ 

So it turns out that these text objects are also pretty handy to select all sorts of function calls and accesses by index. However, there are a few things that fall inside undefined behavior. Consult :help textobj-chainmember-limitations for more information.