RE: [External] : Getting text from next non-blank line

[Drew Adams]

> This interactive function requests the user to input a string
> associated with
> the current line number.  I want to change it so that the function
> picks out
> the text on the current line or the text of the next non-blank line.
> But also
> allow the user to write their own text for the line.
...
>   (interactive "sString: ")

Don't use that, if you want to provide a 
default value for the user input.

Instead, use a function that accepts a
default value.  E.g., `read-string' or
`completing-read'.

Read how to use `interactive' with a
sexp as argument that returns the list
of args you want `interactive' to pass
to the function body.

https://www.gnu.org/software/emacs/manual/html_node/elisp/Using-Interactive.html