RE: Support tab completion for upper character inputs in psql

On Tuesday, September 7, 2021 5:25 PM, Peter Eisentraut  wrote:
>The coding of valid_input_text() seems a bit bulky.  I think you can do  
>the same thing using strspn() without a loop.

Thanks, modified in V9 patch.

>The name is also not great.  It's not like other strings are not "valid".

Modified.
valid_input_text() renamed to check_input_text()

>There is also no explanation why that specific set of characters is  
>allowed and not others.  Does it have something to do with identifier  
>syntax?  This needs to be explained.

Added some comments for pg_string_tolower_if_ascii().
For language like German/Turkish, it's not a good idea to lower the input text 
because the upper case words may not retain the same meaning.(Pointed at [1~3])

>Seeing that valid_input_text() is always called together with  
>pg_string_tolower(), I think those could be combined into one function,  
>like pg_string_tolower_if_ascii() is whatever.  That would save a lot of  
>repetition.

Modified.

>There are a couple of queries where the result is *not*  
>case-insensitive, namely
>
>Query_for_list_of_enum_values
>Query_for_list_of_available_extension_versions
>
>(and their variants).  These are cases where the query result is not  
>used as an identifier but as a (single-quoted) string.  So that needs to  
>be handled somehow, perhaps by adding a COMPLETE_WITH_QUERY_CS() similar  
>to COMPLETE_WITH_CS().

Hmm, I think 'a (single-quoted) string' identifier behaves the same way with or without my patch.
Could your please give me an example on that?(to help me figure out why we need something like COMPLETE_WITH_QUERY_CS())

>(A test case for the enum case should be doable easily.)

Test added.

BTW, I found tap completion for enum value is not perfect on HEAD.
Maybe I will fix this problem in another thread.

example:
=# create type pp_colors as enum ('green', 'blue', 'black');
=# ALTER TYPE pp_colors RENAME VALUE 'b[tab]
=# alter type pp_colors rename value 'b'   <- blue is not auto completed as expected

[1] https://www.postgresql.org/message-id/1282887.1619151455%40sss.pgh.pa.us
[2] https://www.postgresql.org/message-id/20210423.144443.2058612313278551429.horikyota.ntt%40gmail.com
[3] https://www.postgresql.org/message-id/a75a6574c0e3d4773ba20a73d493c2c9983c0657.camel%40cybertec.at

Regards,
Tang