How to I insert a return value from a function call into an existing buffer?

Question

This following vim script calls a function that returns an array called lines:

call vimwiki#diary#generate_diary_section()

There seems to be a bug and nothing is done with the lines array—the content never gets added to the buffer. I have a two part question:

1. How do I capture the array returned from the function? I tried let lines = call ... but that didn't work.

2. How to I dump the lines in the array into the existing file?

Answer 1

There are several ways to insert the return value of a function into a buffer, but the simplest (in my opinion) is to use the expression register:

In normal mode you can trigger the expression register with "=, and then you type an expression and hit enter (<CR>). Thiss can just be a function call, if you wish; then, press p or P to put, as usual. So, "=vimwiki#diary#generate_diary_section()<CR>p.

Alternatively, you can use the :put[!] command:

put =vimwiki#diary#generate_diary_section()

This works linewise.

As for why :call vimwiki#diary#generate_diary_section() doesn't do anything, it's because :call explicitly discards return values. You can :echo to see the value, or use :let to bind it to a variable. But if you just want to insert it directly, :put or p is the way to go.

Answer 2

Just remove call.
This answer did explain the call keyword in vim.