Subject: Re: [PATCH] Updated C# userdiff patterns.

From: Johannes Sixt <[email-masked]>
Date: Sat, 26 Apr 2014 19:49:52 +0200

Am 26.04.2014 11:55, schrieb Marius Ungureanu:
> On 26 Apr 2014, at 10:10, Johannes Sixt <[email-masked]> wrote:
>> Am 26.04.2014 01:25, schrieb Marius Ungureanu:
>>> diff --git a/userdiff.c b/userdiff.c
>>> index fad52d6..7612c5d 100644
>>> --- a/userdiff.c
>>> +++ b/userdiff.c
>>> @@ -133,14 +133,14 @@ PATTERNS("cpp",
>>> 	 "|[-+0-9.e]+[fFlL]?|0[xXbB]?[0-9a-fA-F]+[lLuU]*"
>>> 	 "|[-+*/<>%&^|=!]=|--|\\+\\+|<<=?|>>=?|&&|\\|\\||::|->\\*?|\\.\\*"),
>>> PATTERNS("csharp",
>>> -	 /* Keywords */
>>> -	 "!^[ \t]*(do|while|for|if|else|instanceof|new|return|switch|case|throw|catch|using)\n"
>>> 	 /* Methods and constructors */
>>> -	 "^[ \t]*(((static|public|internal|private|protected|new|virtual|sealed|override|unsafe)[ \t]+)*[][<>@.~_[:alnum:]]+[ \t]+[<>@._[:alnum:]]+[ \t]*\\(.*\\))[ \t]*$\n"
>>> -	 /* Properties */
>>> -	 "^[ \t]*(((static|public|internal|private|protected|new|virtual|sealed|override|unsafe)[ \t]+)*[][<>@.~_[:alnum:]]+[ \t]+[@._[:alnum:]]+)[ \t]*$\n"
>>> +	 "^[ \t]*(((abstract|extern|internal|new|override|private|protected|public|sealed|static|unsafe|virtual)[ \t]+)*[][<>@.~_[:alnum:]]+[ \t]+[<>@._[:alnum:]]+[ \t]*\\(.*\\))[ \t]*$\n"
>>> +	 /* Properties, events, delegates */
>>> +	 "^[ \t]*(((abstract|internal|new|override|private|protected|public|sealed|static|unsafe|virtual)[ \t]+)*((delegate|event)[ \t]+)*[][<>@.~_[:alnum:]]+[ \t]+[@._[:alnum:]]+)[ \t]*$\n"
>>> 	 /* Type definitions */
>>> -	 "^[ \t]*(((static|public|internal|private|protected|new|unsafe|sealed|abstract|partial)[ \t]+)*(class|enum|interface|struct)[ \t]+.*)$\n"
>>> +	 "^[ \t]*(((abstract|internal|new|override|partial|private|protected|public|sealed|static|unsafe)[ \t]+)*(class|enum|interface|struct)[ \t]+.*)$\n"
>>> +	 /* Keywords */
>>> +	 "!^[ \t]*(as|base|break|case|catch|checked|continue|default|delegate|do|else|finally|fixed|for|foreach|if|in|is|lock|new|null|out|readonly|ref|return|switch|this|throw|try|typeof|unchecked|unsafe|using|var|while)\n"
>>> 	 /* Namespace */
>>> 	 "^[ \t]*(namespace[ \t]+.*)$",
>>> 	 /* -- */
> 
> ...
> Modifier parsing can contain keywords, so just to be sure, I moved the
> keywords after modifier parsing, so it uses the keywords as a fallback.
> If this is not what should happen, please tell.

For each line, patterns are are scanned in order, and the first match
determines the outcome: If it is a negative pattern (i.e., it begins
with an exclamation mark), the line is not a hunk header; if it is a
positive pattern, the line is a hunk header. If no pattern matches, the
line is not a hunk header, either; it is as if the list were terminated
by a negative catch-all pattern.

Due to these rules, negative patterns in the list are only necessary
when you want to make an exception to a positive pattern in the list,
and then the negative pattern must be listed before the positive pattern.

In the csharp case, I do not see a pattern of which the keyword pattern
would make an exception (neither the old version nor your new version).
Therefore, you could drop the keyword pattern entirely.

-- Hannes