Re: [RFC 3/8] Add output styles to gdb

[Tom Tromey <tom@tromey.com>]

>>>>> "Simon" == Simon Marchi <simark@simark.ca> writes:

>> "{refcount<10}"

Simon> Do we pass in the values as with printf?  Something like
Simon> ui_out-> format ("{refcount<10}{addr<18}{filename<40}\n", refcount,
Simon> addr, filename);

Nope, the idea is to continue to use the existing ui-out methods.  So
continuing the gdb_bfd example, this code in print_one_bfd:

  uiout->field_int ("refcount", gdata->refc);
  uiout->field_string ("addr", host_address_to_string (abfd));
  uiout->field_string ("filename", bfd_get_filename (abfd));

... would not change at all.

The idea is that the format would be registered as a set/show command
somewhere.  For tables, cli-out could look up the appropriate format
string using the table name; not sure how tuples or lists would work.

Simon> How does the underlying implementation of format knows that the
Simon> refcount variable is an int, and that addr and filename are char*?  We
Simon> go by field name too?  Or should the format specifier contain the data
Simon> type?

The above answers, but basically it would work like today -- the type is
implicit in the ui-out calls, though really at the bottom layer it is
all just strings.

Simon> I tend to think that introducing a format-based system like this is
Simon> relatively orthogonal to the coloring/styling issue.

Part of the overall idea was to let users put styling directly in the
format strings -- sorry, maybe I didn't really spell this out.  So
another example would be

  "{fg=red}{field<40}{fg=default}"

... or something along those lines.  This would conflict a bit with the
idea of styling elements the way that the current patch does it, since
then you'd have to decide what takes precedence.

Though, your note makes me think that this potential conflict really
isn't so bad and we could push forward with the current approach and
deal with more customizable formatting later.

Tom