Re: Coloring error and warning messages in the gui console

[Torsten]

On 10.05.2017 08:33, Daniel J Sebald wrote:
> On 05/10/2017 01:15 AM, Torsten wrote:
>> On 09.05.2017 22:01, Daniel J Sebald wrote:
>>> On 05/09/2017 02:35 PM, Torsten wrote:
>>>> I am currently working on possible ways to color error and warning
>>>> messages in the gui console window. The unix based terminal offers
>>>> filters for highlighting matched "hotspots". Unfortunately, the
>>>> elements
>>>> painted for highlighting lead to ugly artefacts when scrolling.
>>>> Consequently, this filter method is currently only used for underlining
>>>> clickable links (files for opening in the editor or urls) when the
>>>> mouse
>>>> cursor is hovering over them.
>>>>
>>>> For the text colors of error and warning messages I would like to
>>>> insert
>>>> suitable escape sequences into the message strings as implemented in
>>>> the
>>>> patch attached to comment #9 of bug #35619
>>>> (https://savannah.gnu.org/bugs/?35619#comment9)
>>>> Before pushing this patch, I would like to know whether there are any
>>>> objections against changing one of octaves core files (error.cc) only
>>>> for "cosmetic" reasons.
>>>>
>>>> Best,
>>>> Torsten
>>>
>>> Thanks for asking Torsten.  I looked at the patch and I object to this
>>> one on the basis that it implies the core code is doing something GUI
>>> specific, i.e., assigning some color to the errors.  Is that something
>>> that should be done?  I've been against inter-mixing GUI details into
>>> core code from the start, for multiple reasons.  (I drafted a response
>>> to one of Rik's emails a couple weeks back, but hadn't sent it... I will
>>> follow up this email.)
>>>
>>> The proper way to do this, as I see it, is for the core to allow some
>>> routine to access the previous error(s), whether that is a function or
>>> some type of script command.  (Unfortunately, there has always been
>>> lacking the simple method of calling a script from the GUI and getting
>>> an octave_value_list in return.)  That is, when there is an error, the
>>> core should have a log of what happened (a unique error message or
>>> classification) and the line number and file where it happened.  There
>>> should also be a list of available error messages, for which the GUI can
>>> assign the color scheme however it wants.  The steps would be:
>>>
>>> 1) GUI recognizes error occurred
>>> 2) GUI inquires what the error was
>>> 3) GUI cross references error message in the list of possible messages
>>> 4) GUI uses the index from the cross reference to look up color in its
>>> own table
>>>
>>> Dan
>>
>> Dan, thank you for the reply. Just to clarify, the selection of the
>> color is done by the GUI depending on the user's settings. The core is
>> just interspersing esc-sequences for the GUI's terminal emulation into
>> the output stream depending on warning or error. This might later be
>> used for the cli-version, too, if the terminal emulation is known.
>>
>> When I understand your approach correctly, the core would have to wait
>> during the four steps of the GUI before actually printing the message?
>> Wouldn't this have much more impact on the core? Or should the GUI
>> buffer the stream and search later for the appropriate positions for
>> changing color before printing?
>>
>> Torsten
> 
> You're saying that the changes then are really not GUI-specific, but
> more generally the console.  That is, when I run octave-cli, I should
> see errors and warnings in color in the shell console as well?  I
> suppose that is more core/interpreter centric.  Is there to be some
> script that can be used to configure the colors or turn them off from
> the command line?  If so, then that is again core-centric.  (Perfectly
> fine having configuration in the GUI somewhere--that ultimately calls
> said configuration script.)
> 
> I thought I read in the bug/feature discussion that one goal is to make
> clicking on the error message jump to the location of the code in the
> GUI editor.  That is more GUI-related, unless the console can be set up
> to initiate such a jump via the core, say something like the "edit"
> routine.  Is this something separate from the color idea?  How is the
> GUI getting the information about the line number?
> 
> Dan

Clickable links are already implemented in the linux gui console window
using the existing concept of filters. The attached patch is just for
coloring the text of error messages in the gui console window by
inserting the respective escape sequences into the text strings.

Torsten