How to set opfunc to a lambda function?

Question

I've found it's common to set opfunc in this manner:

nnoremap <Leader>r :set opfunc=<SID>my_function<CR>g@

With Vim8 supporting lambda functions, is it possible to now set opfunc to a lambda function? The following cursory try did not work:

:set opfunc={-> "test" }

Ralf · Accepted Answer · 2019-02-18T08:40:14.720

5

The operatorfunc is a option. A option can only have the types boolean (on/off), number or string (see :help options). So you can't assign a lambda to an option.

Also the documentation help 'operatorfunc' says

This option specifies a function to be called by the g@ operator.

My interpretation of "specifies" is "names".

I had a look at the code (function op_function in normal.c). It calls a vim script function by name.

So the answer is: No

edited Feb 18 '19 at 08:40

answered Feb 17 '19 at 18:25

Ralf

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You're implying that lambdas are not functions? From the Vim manual: A lambda expression creates a new unnamed function ... – Roxy Feb 17 '19 at 23:39
@Roxy See update – Ralf Feb 18 '19 at 06:22
I suppose it's also not possible to use a funcref in this spot, even let Q=function("Bar'), set opfunc=Q though call Q() works. – Mass Feb 18 '19 at 18:21
@Mass Correct. Its a String option, so you can only set a name. – Ralf Feb 18 '19 at 18:39
don't ever do this!: let Q = {->execute('quit')} | let &opfunc=get(Q,'name') :) – Mass Feb 18 '19 at 20:45

How to set opfunc to a lambda function?

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