Subject: Re: bug#70622: [PATCH] New window parameter 'cursor-type'

From: martin rudalics <[email-masked]>
Date: Sat, 11 May 2024 09:35:37 +0200

>>   >> Shouldn't we validate the value of TYPE before plugging it into the
 >>   >> window?  I know we will validate it at display time, but maybe it's a
 >>   >> good idea to do that here as well, and signal an error up front?
 >>   >
 >>   > AFAICT there are no invalid values, since we take "any other value" to
 >>   > mean the same as 'hollow' (see C-h v cursor-type), so I think not
 >>   > validating anything should be perfectly valid :)
 >>   >
 >>   >> Martin, WDYT?
 >>
 >> I think Eshel is right.
 >
 > Any reasons?

The doc-string of the variable 'cursor-type' states that

     cursor-type is a variable defined in ‘C source code’.

     Its value is t

     Cursor to use when this buffer is in the selected window.
     Values are interpreted as follows:

       t               use the cursor specified for the frame
       [...]
       ANYTHING ELSE   display a hollow box cursor

Suppose the buffer value is ANYTHING ELSE, someone wants to temporarily
change it for a specific window and later wants to reset it back to its
buffer value via 'set-window-cursor-type'.  Should Emacs signal an error
up front in that case?

martin