Re: REQUEST - bash floating point math support

[Léa Gris]

Le 17/06/2024 à 09:17, Koichi Murase écrivait :
>    declare -i numvar=${localeFormatted/[!0-9]/.}

This would break with negative numbers.

I know no other radix separator than comma or dot. If there are other 
radix to replace, it can be listed in a character class.

Lets say there are locales that uses , ; or :

declare -i numvar=${localeFormatted/[,;:]/.}

> In my opinion, the locale-formatted strings should only appear in the
> strings presented to users, such as in the output of `printf'. It is
> easier and maintainable to normalize all the internal representations
> to be the C floating-point literals.

I have been in IT in France since 3 decades. And I have never ever found 
any piece of code that use locale-formatted literals, not even during my 
CS education.

Sometimes one have to deal with data sources with numbers formatted in 
funny ways, even grouping with illegal characters. Then it is a know 
fact that one must deal with sourced data with zealous sanitizing.

Now on the bash shell context. The usual pitfall with floating-point 
number parsing comes when some script author tries to parse output of a 
command that is not meant to be parsed, that is locale formatted and 
don't bother to set LC_NUMERIC=C before running this command

A common pitfall is trying to parse the output of the time builtin command.

It already breaks on locale ignorant scripts. This won't change.

--
Léa Gris