How to debug indentation

How to debug indentation

[N. Raghavendra]

I am trying to debug nXML mode indentation.  As a way of seeing what
functions like `nxml-indent-line' and `nxml-compute-indent' do, I am
inserting `message' forms at various places in these functions, and
looking at the *Messages* buffer to see what has happened.  However, I
am finding this method cumbersome.

Is there a more systematic way of doing this?  Is it possible to use
Edebug to debug indentation?  Or any other methods?

Thanks,
Raghu.

--
N. Raghavendra <raghu@hri.res.in>, http://www.retrotexts.net/
Harish-Chandra Research Institute, http://www.hri.res.in/

Re: How to debug indentation

[N. Raghavendra]

At 2018-05-25T08:28:31+05:30, N. Raghavendra wrote:

> I am trying to debug nXML mode indentation.  As a way of seeing what
> functions like `nxml-indent-line' and `nxml-compute-indent' do, I am
> inserting `message' forms at various places in these functions, and
> looking at the *Messages* buffer to see what has happened.  However, I
> am finding this method cumbersome.

I meant that after inserting the message forms, I open a test XML file,
go to various lines, press TAB, and see the messages that are generated.

> Is there a more systematic way of doing this?  Is it possible to use
> Edebug to debug indentation?  Or any other methods?
>
> Thanks,
> Raghu.

-- 
N. Raghavendra <raghu@hri.res.in>, http://www.retrotexts.net/
Harish-Chandra Research Institute, http://www.hri.res.in/

Re: How to debug indentation

[Stefan Monnier]

> I am trying to debug nXML mode indentation.  As a way of seeing what
> functions like `nxml-indent-line' and `nxml-compute-indent' do, I am
> inserting `message' forms at various places in these functions, and
> looking at the *Messages* buffer to see what has happened.  However, I
> am finding this method cumbersome.

If the indentation code is spread over several functions,
`trace-function` can be useful as well (along with insertion of
`trace-values` calls).

> Is there a more systematic way of doing this?  Is it possible to use
> Edebug to debug indentation?

Yes, I often use Edebug to debug indentation problems.


        Stefan

Re: How to debug indentation

[N. Raghavendra]

At 2018-05-25T01:24:01-04:00, Stefan Monnier wrote:

> If the indentation code is spread over several functions,
> `trace-function` can be useful as well (along with insertion of
> `trace-values` calls).

I can see what `trace-function' does, but can't make out how to use
`trace-values'.  I saw trace.el, but there is no documentation there
about it.  Can you give some idea of how to use it?

> Yes, I often use Edebug to debug indentation problems.

I am now able to use Edebug to see how the indentation is working.

Thanks,
Raghu.

-- 
N. Raghavendra <raghu@hri.res.in>, http://www.retrotexts.net/
Harish-Chandra Research Institute, http://www.hri.res.in/

Re: How to debug indentation

[Michael Heerdegen]

"N. Raghavendra" <nyraghu27132@gmail.com> writes:

> I can see what `trace-function' does, but can't make out how to use
> `trace-values'.  I saw trace.el, but there is no documentation there
> about it.

It has a docstring.

>  Can you give some idea of how to use it?

AFAICT you just place into in the code, reevaluate, and it will print
values into the trace buffer.  E.g.

(defun fac (x)
  (trace-values (cons 'x x))
  (if (< x 2) 1 (* x (fac (1- x)))))

Tracing `fac' and evaluating (fac 3) gives you a trace buffer like

1 -> (fac 3)
1 -> (trace-values (x . 3))
  2 -> (fac 2) 
  2 -> (trace-values (x . 2))
    3 -> (fac 1)
    3 -> (trace-values (x . 1))
    3 <- fac: 1
  2 <- fac: 2
1 <- fac: 6

Nothing more.


Michael.

Re: How to debug indentation

[N. Raghavendra]

At 2018-05-26T03:41:03+02:00, Michael Heerdegen wrote:

> AFAICT you just place into in the code, reevaluate, and it will print
> values into the trace buffer.  E.g.
>
> (defun fac (x)
>   (trace-values (cons 'x x))
>   (if (< x 2) 1 (* x (fac (1- x)))))
>
> Tracing `fac' and evaluating (fac 3) gives you a trace buffer like
>
> 1 -> (fac 3)
> 1 -> (trace-values (x . 3))
>   2 -> (fac 2)
>   2 -> (trace-values (x . 2))
>     3 -> (fac 1)
>     3 -> (trace-values (x . 1))
>     3 <- fac: 1
>   2 <- fac: 2
> 1 <- fac: 6
>
> Nothing more.

That's helpful.  I'll try that.

Thanks,
Raghu.

--
N. Raghavendra <raghu@hri.res.in>, http://www.retrotexts.net/
Harish-Chandra Research Institute, http://www.hri.res.in/