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

[martin rudalics]

>>   >> 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