Re: [GSOC][PATCH] userdiff: add support for Scheme

[Atharva Raykar <raykar.ath@gmail.com>]

On 28-Mar-2021, at 05:16, Johannes Sixt <j6t@kdbg.org> wrote:
>> diff --git a/t/t4018/scheme-define-syntax b/t/t4018/scheme-define-syntax
>> new file mode 100644
>> index 0000000000..603b99cea4
>> --- /dev/null
>> +++ b/t/t4018/scheme-define-syntax
>> @@ -0,0 +1,8 @@
>> +(define-syntax define-test-suite RIGHT
>> +  (syntax-rules ()
>> +    ((_ suite-name (name test) ChangeMe ...)
>> +     (define suite-name
> 
> This test is suspicious. Notice the "ChangeMe" above? That is sufficient
> to let the test case succeed. The "ChangeMe" in the last line below
> should be the only one.

Thanks for pointing this out. The second "ChangeMe" was not supposed to be
there.

What I wanted to test was the hunk header showing the line for
'(define-syntax ...' and not the internal '(define ...' below it. Thus the
ChangeMe should be located above the internal define so that the hunk header
would show define-syntax and not the local define.

> But then there is this indented '(define' that is not marked as RIGHT,
> and I wonder how is it different from...
> 
>> +       (let ((tests
>> +              `((name . ,test) ...)))
>> +         (lambda ()
>> +           (ChangeMe 'suite-name tests)))))))
>> \ No newline at end of file
>> diff --git a/t/t4018/scheme-local-define b/t/t4018/scheme-local-define
>> new file mode 100644
>> index 0000000000..90e75dcce8
>> --- /dev/null
>> +++ b/t/t4018/scheme-local-define
>> @@ -0,0 +1,4 @@
>> +(define (higher-order)
>> +  (define local-function RIGHT
> 
> ... this one, which is also indented and *is* marked as RIGHT.

In this test case, I was explicitly testing for an indented '(define'
whereas in the former, I was testing for the top-level '(define-syntax',
which happened to have an internal define (which will inevitably show up
in a lot of scheme code).

>> +    (lambda (x)
>> +     (car "this is" "ChangeMe"))))
>> \ No newline at end of file
> 
>> diff --git a/userdiff.c b/userdiff.c
>> index 3f81a2261c..c51a8c98ba 100644
>> --- a/userdiff.c
>> +++ b/userdiff.c
>> @@ -191,6 +191,14 @@ PATTERNS("rust",
>> 	 "[a-zA-Z_][a-zA-Z0-9_]*"
>> 	 "|[0-9][0-9_a-fA-Fiosuxz]*(\\.([0-9]*[eE][+-]?)?[0-9_fF]*)?"
>> 	 "|[-+*\\/<>%&^|=!:]=|<<=?|>>=?|&&|\\|\\||->|=>|\\.{2}=|\\.{3}|::"),
>> +PATTERNS("scheme",
>> +         "^[\t ]*(\\(define-?.*)$",
> 
> This "optional hyphen followed by anything" in the regex is strange.
> Wouldn't that also capture a line that looks like, e.g.,
> 
>    (defined-foo bar)
> 
> Perhaps we want "define[- \t].*" in the regex?

Yes, this is what I intended to do, thanks for correcting it.