format function

[Chaubert Jérôme]

Hi,
I think there is a bug with "format" function with accented characters :
(format nil "%03s" "é")
return "0é". It should be "00é", isn't it ?

Note : this is not new : the bug (if it is indeed a bug) also existed in 6.3 but I was able to correct it thanks to the difference in results of (length$ "é") and (str-length "é") but now (with 6.4.1) (length$ "é") is not supported anymore.

[Gary Riley]

I'll look into it. You can use str-length where you previously used length$.

[Gary Riley]

I checked in fixes for the format function to adjust the width and precision when multibyte characters are present in a string. I noticed when digging through the specifications for conversion characters for the printf function that the behavior for using 0 with the s conversion character isn't specified. On macOS/Xcode and Windows/Visual Studio, the padding uses 0, but on Linux it uses spaces.

[Chaubert Jérôme]

Thank you for the fix. It works perfectly.

About the "0" behaviour : it's not a problem for me. I used "0" to be more explicit in my description but I don't really use this pattern.

[Chaubert Jérôme]

Thanks. I let you see.
(In this context I can't use str-length insteed of length$ because in 6.3
(str-length "é") => 1
but
(length$ "é") => 2
And I use this difference between two function results to get round the problem of "format" (described above).)

[Chaubert Jérôme]

Can you give me some news about this problem ? Have you found a solution ?

[Gary Riley]

I looked through the format code and I'm going to have to do some more sophisticated parsing of the format string to automatically adjust the lengths to handle multibyte UTF-8 characters. For now, since length$ served as a workaround in prior versions, I added a function called str-byte-length:

                           CLIPS (6.4.2 4/12/24)
CLIPS> (str-length "e")
1
CLIPS> (str-byte-length "é")
2
CLIPS> 

[Chaubert Jérôme]

OK. Thanks a lot! I will import your new code and use str-byte-length for my workaround (for now).

[Chaubert Jérôme]

The str-byte-length function (together with my workaround of "format" function) works perfectly well. Thanks a lot.