call a function with buffer as temporary current buffer

This temporarily switches current buffer to "buffer". If the current window already shows "buffer", the window is not switched If a window inside the current tabpage (including a float) already shows the buffer One of these windows will be set as current window temporarily. Otherwise a temporary scratch window (called the "autocmd window" for historical reasons) will be used.

This is useful e.g. to call vimL functions that only work with the current buffer/window currently, like termopen().

Attributes: Lua vim.api only

Parameters:

• {buffer} Buffer handle, or 0 for current buffer
• {fun} Function to call inside the buffer (currently lua callable only)

Return: Return value of function. NB: will deepcopy lua values currently, use upvalues to send lua references in and out.