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

>
> Hi
>
> On Thu, May 16, 2019 at 10:29 PM Johannes Sixt <j6t@kdbg.org> wrote:
> >
> > 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.
>
> Oops, thanks!
>
> >
> > 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.
>
> yes, but with
>
> extern ( space* '"' stuff '"' )?
>
> I'll try that
>

> >
> > > +      /* -- */
> > > +      "[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).
>
> That doesn't capture 0o70, easy to fix.
>
> Then it doesn't capture the examples from the reference manual:
> 123.0f64;
> 0.1f64;
> 0.1f32;
> 12E+99_f64;
>
> Thanks for your help!
>
> >
> > > +      "|[-+*\\/<>%&^|=!:]=|<<=?|>>=?|&&|\\|\\||->|=>|\\.{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