Re: [PATCH] userdiff: add builtin driver for kotlin language

From: Jaydeep Das <jaydeepjd.8914@gmail.com>
Date: Mar 4, 2022, 12:28 UTC
Message-ID: <90596af6-0158-beb9-7fa7-9237e7cff4fb@gmail.com>
In-Reply-To: <c1298c9d-0f4a-40b8-b337-896f4d4777f3@kdbg.org>

On 3/4/22 01:34, Johannes Sixt wrote:

Show 7 quoted lines

> Am 03.03.22 um 12:41 schrieb Jaydeep Das:
>> How about modifying the number match regex to:
>>
>> `[0-9._]+([Ee][-+]?[0-9]+)?[fFlLuU]*[^a-zA-Z]` ?
>>
>> The `[^a-zA-Z]` in the end would make sure to not match
>> the `.F` in `X.Find`.

> No, you cannot do that, because then in X.u+1 you have three tokens X
> .u+ 1, which you do not want, either.

If X is an integer here, then

In C/C++ 2.f is equivalent to 2.000000 However in Kotlin 2.f is invalid syntax. 2.0f is valid.

So is implementing a proper regex for invalid syntax really necessary?

> But then you can use the regex you had in the first round:
> 
>     [a-zA-Z_][a-zA-Z0-9_]*

Right. I will change that.

Show 16 quoted lines

>> Numbers: `[0-9_.]+([Ee][-+]?[0-9]+)?[fFlLuU]*[^a-zA-Z]`
>> (It makes sure that in X.Find, .F is not matched )
>>
>> Additionally, An extra regex for method calls:
>>
>> `[.][a-zA-Z()0-9]+`
>>
>> What do you think?
> 
> Have a look at the regex in the cpp driver. I think we need something
> like this:
> 
>    /* integers floatingpoint numbers */
>    "|[0-9][0-9_.]*([Ee][*-]?[0-9]+)?[FfLl]*"
>    /* floatingpoint numbers that begin with a decimal point */
>    "|[.][0-9][0-9_]*([Ee][*-]?[0-9]+)?[FfLl]*"

> Drop the second option if numbers such as .5 are invalid syntax in Kotlin.

.5 is valid syntax in Kotlin.

-- Thanks, Jaydeep.