Re: [PATCH] RFC: userdiff: add built-in pattern for rust

>
> Am 15.05.19 um 20:34 schrieb marcandre.lureau@redhat.com:
> > From: Marc-André Lureau <mlureau@redhat.com>
> >
> > This adds xfuncname and word_regex patterns for Rust, a quite
> > popular programming language. It also includes test cases for the
> > xfuncname regex (t4018) and updated documentation.
> >
> > The word_regex pattern finds identifiers, integers, floats and
> > operators, according to the Rust Reference Book.
> >
> > RFC: since I don't understand why when there are extra lines such as the
> > one with FIXME, the funcname is not correctly reported. Help welcome!
> >
> > Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
> > ---
> >  Documentation/gitattributes.txt | 2 ++
> >  t/t4018-diff-funcname.sh        | 1 +
> >  t/t4018/rust-fn                 | 5 +++++
> >  t/t4018/rust-struct             | 5 +++++
> >  t/t4018/rust-trait              | 5 +++++
>
> Nice to see tests!
>
> > diff --git a/userdiff.c b/userdiff.c
> > index 3a78fbf504..9e1e2fa03f 100644
> > --- a/userdiff.c
> > +++ b/userdiff.c
> > @@ -130,6 +130,15 @@ PATTERNS("ruby", "^[ \t]*((class|module|def)[ \t].*)$",
> >        "(@|@@|\\$)?[a-zA-Z_][a-zA-Z0-9_]*"
> >        "|[-+0-9.e]+|0[xXbB]?[0-9a-fA-F]+|\\?(\\\\C-)?(\\\\M-)?."
> >        "|//=?|[-+*/<>%&^|=!]=|<<=?|>>=?|===|\\.{1,3}|::|[!=]~"),
> > +PATTERNS("rust",
> > +      "^[\t ]*(((pub|pub\\([^)]+\\))[\t ]+)?(struct|enum|union|mod)[ \t].*)$\n"
> > +      "^[\t ]*(((pub|pub\\([^)]+\\))[\t ]+)?(unsafe[\t ]+)?trait[ \t].*)$\n"
> > +      "^[\t ]*(((pub|pub\\([^)]+\\))[\t ]+)?((const|unsafe|extern(([\t ]+)*\"[^)]+\")?)[\t ]+)*fn[ \t].*)$\n",
>
> The last \n there is the reason for the test failures: it adds an empty
> pattern that matches everywhere and does not capture any text.

>
> Can we simplify these patterns as in
>
>    ^
>    space*
>    ( pub ( "(" stuff ")" )? space* )?
>    ( struct|enum|union|mod|unsafe|trait|const|extern|fn )
>    stuff
>    $
>
> You don't have to check for a correct syntax rigorously because you can
> assume that only correct Rust code will be passed to the patterns.

>
> > +      /* -- */
> > +      "[a-zA-Z_][a-zA-Z0-9_]*"
> > +      "|[-+_0-9.eE]+(f32|f64|u8|u16|u32|u64|u128|usize|i8|i16|i32|i64|i128|isize)?"
>
> I assume that
>
>        +e_1.ei8-e_2.eu128
>
> is correct syntax, but not a single token. Yet, your number pattern
> would take it as a single word.
>
> > +      "|0[box]?[0-9a-fA-F_]+(u8|u16|u32|u64|u128|usize|i8|i16|i32|i64|i128|isize)?"
>
> You should really subsume your number patterns under a single pattern
> that requires an initial digit, because you can again assume that only
> correct syntax will be shown to the patterns:
>
>         "|[0-9][0-9_a-fA-Fuisxz]*([.][0-9]*([eE][+-]?[0-9]+)?)?"
>
> (very likely, I have mistaken the meaning of f32 and f64 here).

>
> > +      "|[-+*\\/<>%&^|=!:]=|<<=?|>>=?|&&|\\|\\||->|=>|\\.{2}=|\\.{3}|::"),
> >  PATTERNS("bibtex", "(@[a-zA-Z]{1,}[ \t]*\\{{0,1}[ \t]*[^ \t\"@',\\#}{~%]*).*$",
> >        "[={}\"]|[^={}\" \t]+"),
> >  PATTERNS("tex", "^(\\\\((sub)*section|chapter|part)\\*{0,1}\\{.*)$",
> >
> > base-commit: ab15ad1a3b4b04a29415aef8c9afa2f64fc194a2
> >
>
> -- Hannes