Re: [PATCH v6] userdiff: add builtin diff driver for kotlin language.

[Johannes Sixt <j6t@kdbg.org>]

Am 11.03.22 um 08:27 schrieb Jaydeep P Das:
> The xfuncname pattern finds func/class declarations
> in diffs to display as a hunk header. The word_regex
> pattern finds individual tokens in Kotlin code to generate
> appropriate diffs.
> 
> This patch adds xfuncname regex and word_regex for Kotlin
> language.
> 
> Signed-off-by: Jaydeep P Das <jaydeepjd.8914@gmail.com>
> ---

Thank you. At first, I thought this round is it, but then I noticed this
line:

> +<RED>0xFF_EC_DE_5E 0b100_000 1<RESET><GREEN>0xFF_E1_DE_5E 0b100_100 2<RESET>00_000

Notice how the change from 100_000 to 200_000 breaks out the first digit
into its own token.

> diff --git a/userdiff.c b/userdiff.c
> index 8578cb0d12..c416c9b426 100644
> --- a/userdiff.c
> +++ b/userdiff.c
> @@ -168,6 +168,18 @@ PATTERNS("java",
>  	 "|[-+0-9.e]+[fFlL]?|0[xXbB]?[0-9a-fA-F]+[lL]?"
>  	 "|[-+*/<>%&^|=!]="
>  	 "|--|\\+\\+|<<=?|>>>?=?|&&|\\|\\|"),
> +PATTERNS("kotlin",
> +	 "^[ \t]*(([a-z]+[ \t]+)*(fun|class|interface)[ \t]+.*)$",
> +	 /* -- */
> +	 "[a-zA-Z_][a-zA-Z0-9_]*"
> +	 /* hexadecimal and binary numbers */
> +	 "|0[xXbB][0-9a-fA-F_]+[lLuU]*"
> +	 /* integers and floats */
> +	 "|[0-9][0-9_]*([.][0-9_]*)([Ee][-+]?[0-9]+)?[fFlLuU]*"

This line matches a non-empty digit sequence of any length, and I
thought the longest match would win. Why is that not the case here?
Frankly, I'm scratching my head over it. Any ideas?

> +	 /* floating point numbers beginning with decimal point */
> +	 "|[.][0-9][0-9_]*([Ee][-+]?[0-9]+)?[fFlLuU]?"
> +	 /* unary and binary operators */
> +	 "|[-+*/<>%&^|=!]==?|--|\\+\\+|<<=|>>=|&&|\\|\\||->|\\.\\*|!!|[?:.][.:]"),
>  PATTERNS("markdown",
>  	 "^ {0,3}#{1,6}[ \t].*",
>  	 /* -- */

-- Hannes