Re: [PATCH] gnu-maintenance: update-package-source: Only update the desired package.

[Andy Wingo <wingo@igalia.com>]

Hi :)

On Tue 05 Apr 2016 16:05, iyzsong@member.fsf.org (宋文武) writes:

> Andy Wingo <wingo@igalia.com> writes:
>
>> In that case I think the ideal is something like "edit-expression",
>> which takes a source location that starts an expression, uses "read" to
>> advance to the end of the expression, then edits the intervening string
>> using whatever but verifies that the result can still be read as one
>> expression.  Having recorded the absolute byte positions of the start
>> and end of the expression, you can then create the output by doing an
>> efficient bytevector read of the prologue, then display the string for
>> the edited expression, then the bytevector tail.
>>
>> Again, just a thought!  Feel free to incorporate or not as you like,
>> 宋文武 :)
> Indeed this is better!  To create the output from bytevector, it's
> using `get-bytevector-n' to read and `utf8->string' to write, right?

Hmm, good question.  I think I would use put-bytevector, if I read using
get-bytevector-n, assuming that the encoding of the input and the output
ports were the same.  Probably it is worth making sure that you set the
encodings to be the same, but I don't know :)  Hopefully everything is
UTF-8 these days.

> And I think `edit-expression' could be:
> (define (edit-expression source-properties proc)
>   "Edit the object specified by SOURCE-PROPERTIS using PROC, which
> should be a procedure that take the original object and returns
> a new one."
>   ...)

Yeah :)  However probably the "proc" should take and return a string, so
as to preserve formatting and comments.

Good luck :)

Andy