[Edbrowse-dev] Problem installing git version on debian sid

[Edbrowse-dev] Problem installing git version on debian sid

[Chuck Hallenbeck]

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Hi folks,

I have recently been using the edbrowse 3.7.1 package provided by
my package manager on two systems here, debian sid, and archlinux.
I wanted to switch to the git version on both systems, with these
results:

On archlinux, I did a git clone using the URL shown on
www.edbrowse.org, changed to the edbrowse/src directory, did a make
as normal user, and got a successful compile.

On Debian however, the make failed  because of a missing tidy.h  file.
So I then retrieved the latest tidy-html5  master.zip as per the
README, but that compile failed also, because cmake was unable to
successfully compile the simple test program.  Evidently it did not
locate the cxx compiler, which on Debian sid seems to be called cpp,
a simlink to cpp-7, and I'm not sure what to try next.

I repeated the  process capturing the output, and include it below,
about 65 lines.  Any suggestions are most welcome.

Script started on 2017-12-04 02:37:44-0500
[archie@debian cmake]$ cmake ../..
-- The C compiler identification is GNU 7.2.0
-- The CXX compiler identification is unknown
-- Check for working C compiler: /usr/bin/cc
-- Check for working C compiler: /usr/bin/cc -- works
-- Detecting C compiler ABI info
-- Detecting C compiler ABI info - done
-- Detecting C compile features
-- Detecting C compile features - done
-- Check for working CXX compiler: /usr/bin/cpp
-- Check for working CXX compiler: /usr/bin/cpp -- broken
CMake Error at /usr/share/cmake-3.9/Modules/CMakeTestCXXCompiler.cmake:44 (message):
   The C++ compiler "/usr/bin/cpp" is not able to compile a simple test
   program.

   It fails with the following output:

    Change Dir: /home/archie/src/tidy-html5-master/build/cmake/CMakeFiles/CMakeTmp



   Run Build Command:"/usr/bin/make" "cmTC_97a4d/fast"

   /usr/bin/make -f CMakeFiles/cmTC_97a4d.dir/build.make
   CMakeFiles/cmTC_97a4d.dir/build

   make[1]: Entering directory
   '/home/archie/src/tidy-html5-master/build/cmake/CMakeFiles/CMakeTmp'

   Building CXX object CMakeFiles/cmTC_97a4d.dir/testCXXCompiler.cxx.o

   /usr/bin/cpp -o CMakeFiles/cmTC_97a4d.dir/testCXXCompiler.cxx.o -c
   /home/archie/src/tidy-html5-master/build/cmake/CMakeFiles/CMakeTmp/testCXXCompiler.cxx


   cpp: fatal error: ‘-c’ is not a valid option to the preprocessor

   compilation terminated.

   CMakeFiles/cmTC_97a4d.dir/build.make:65: recipe for target
   'CMakeFiles/cmTC_97a4d.dir/testCXXCompiler.cxx.o' failed

   make[1]: *** [CMakeFiles/cmTC_97a4d.dir/testCXXCompiler.cxx.o] Error 1

   make[1]: Leaving directory
   '/home/archie/src/tidy-html5-master/build/cmake/CMakeFiles/CMakeTmp'

   Makefile:126: recipe for target 'cmTC_97a4d/fast' failed

   make: *** [cmTC_97a4d/fast] Error 2





   CMake will not be able to correctly generate this project.
Call Stack (most recent call first):
   CMakeLists.txt:26 (project)


-- Configuring incomplete, errors occurred!
See also "/home/archie/src/tidy-html5-master/build/cmake/CMakeFiles/CMakeOutput.log".
See also "/home/archie/src/tidy-html5-master/build/cmake/CMakeFiles/CMakeError.log".
[archie@debian cmake]$ exit

Script done on 2017-12-04 02:39:06-0500


I appreciate all the work you folks have been doing and am anxious
to see some of those improvements in action.

Chuck H.


-- 
Here In Northeast Ohio, The Moon is Waning Gibbous (99% of Full)
When your only tool is a hammer, everything looks like a nail.
Sent from Dianna's iPhone.

Re: [Edbrowse-dev] Problem installing git version on debian sid

[Geoff McLane]

Hi Chuck,

Concerning HTML Tidy, not sure what you refer to when you say 
'master.zip'? What README?

We have just released 5.6.0, and that should be 5.6.0.zip, or if you 
want to build from the repo -
$ git checkout master
$ git pull
and the version.txt file should contain 5.6.0, 2017.11.25, being the 
latest release...

But concerning your problem, not sure I really have the answer, but 
cmake should be able to find a working cxx/cpp compiler in your system...

My cmake 3.2.2 in Ubuntu linux, 14.04 shows "Check ... /usr/bin/c++ -- 
works"...

Actually tidy does not require cxx/cpp - it is a pure C project - and 
you could add this to the CMakeLists.txt, like change the line -
project (${LIB_NAME})
to
project (${LIB_NAME} C)

And that will tell cmake to ONLY look for a C compiler... and might get 
tidy 5.6.0 built...

But you will still need a cxx/cpp compiler for 'edbrowse', since it 
likewise has only cmake 'project (edbrowse)', in its CMakeLists.txt, 
which without the [LANGUAGE] option will likewise try to test both C and 
CXX by default, whether actually needed or not...

The real question is why is your Debian sid failing on this most basic 
of cmake tests? A cxx/cpp compiler should be installed...

I hope others can address that...

HTH, Geoff.

Re: [Edbrowse-dev] Problem installing git version on debian sid

[Chuck Hallenbeck]

Hi Jeff,

On Mon, 4 Dec 2017, Geoff McLane wrote:

> Hi Chuck,
>
> Concerning HTML Tidy, not sure what you refer to when you say 'master.zip'? 
> What README?

The README is in the edbrowse directory created by the git-clone . It 
says to retrieve 
https://github.com/htacg/tidy-html5/archive/master.zip


>
> We have just released 5.6.0, and that should be 5.6.0.zip, or if you want to 
> build from the repo -
> $ git checkout master
> $ git pull
> and the version.txt file should contain 5.6.0, 2017.11.25, being the latest 
> release...


Not sure how to get the 5.6.0 package from the above. 
>
> But concerning your problem, not sure I really have the answer, but cmake 
> should be able to find a working cxx/cpp compiler in your system...
>
> My cmake 3.2.2 in Ubuntu linux, 14.04 shows "Check ... /usr/bin/c++ -- 
> works"...
>
> Actually tidy does not require cxx/cpp - it is a pure C project - and you 
> could add this to the CMakeLists.txt, like change the line -
> project (${LIB_NAME})
> to
> project (${LIB_NAME} C)
>
> And that will tell cmake to ONLY look for a C compiler... and might get tidy 
> 5.6.0 built...
>
> But you will still need a cxx/cpp compiler for 'edbrowse', since it likewise 
> has only cmake 'project (edbrowse)', in its CMakeLists.txt, which without the 
> [LANGUAGE] option will likewise try to test both C and CXX by default, 
> whether actually needed or not...
>
> The real question is why is your Debian sid failing on this most basic of 
> cmake tests? A cxx/cpp compiler should be installed...

Well actually it is installed at /usr/bin/cpp, which is a symlink to 
cpp-7 in the same directory.  But that produced the error when 
attempting to compile the test program.  The error said the option -c 
was not recognized by the preprocessor. .

>
> I hope others can address that...
>
> HTH, Geoff.
Thanks for your response ... I'm not sure I'm quite up to this.



>
> _______________________________________________
> Edbrowse-dev mailing list
> Edbrowse-dev@lists.the-brannons.com
> http://lists.the-brannons.com/mailman/listinfo/edbrowse-dev
>

-- 
Here In Northeast Ohio, The Moon is Waning Gibbous (98% of Full)
When your only tool is a hammer, everything looks like a nail.
Sent from Yvette's iPhone.

Re: [Edbrowse-dev] Problem installing git version on debian sid

[Chuck Hallenbeck]

Jeff,

I just took a look at the version file in the directory created by 
unzipping master.zip, and guess what? It's 5.6.0 with the date you 
indicated. 
But I don't know what to think about the failure of cpp to pass the 
simple compile test. I've never done anything to change the default 
installation of my C/C++ compilers.

So, to summarize: I used wget to retrieve the tidy-html5 as described in 
the edbrowse README, then unzipped it, and it gives me the source tree 
with 5.6.0 in the version file. But it won't compile.

Chuck

-- 
Here In Northeast Ohio, The Moon is Waning Gibbous (98% of Full)
When your only tool is a hammer, everything looks like a nail.
Sent from Tracy's iPhone.

Re: [Edbrowse-dev] Problem installing git version on debian sid

[Geoff McLane]

On 04/12/17 20:48, Chuck Hallenbeck wrote:
>
> ... . It says to retrieve 
> https://github.com/htacg/tidy-html5/archive/master.zip

Yes, as you point out, that certain seems to be the correct 5.6.0 
2017.11.25 master source, so no problem there...

>
>   ... The error said the option -c was not recognized by the 
> preprocessor. .

Well that -c option is one of the most common options - it means compile 
and assemble but do not link - must be supported by all gcc compilers... 
in my system $ gcc --version, $ cpp --version, $ c++ --version all 
appear to be the **same** thing...


As stated -
>>
>> I hope others can address that...
>>
I am sure there must be a simple explanation... if it compiles in one, 
should also in others... keep trying... sure you will get there...

Regards, Geoff.

[Edbrowse-dev] Problem installing git version on debian sid

[Karl Dahlke]

I am rather confused by all this.

> The error said the option -c was not recognized by the preprocessor.

Of course not.
cpp is the c preprocessor, the program that expands all the #ifdefs #includes etc.
It's basically a macro expander, very specific to C.
It doesn't know anything about the C language or compilation or objects or linkage or anything else.
It's a front end program, and you shouldn't be calling it with -c or any of the compiler options.
If you want the c++ compiler you need c++ or g++ or some such.
It's damn confusing, since c++ files end in the extension .cpp, but no, that doesn't mean you should call cpp on them.
And I don't think any of tidy is c++, so that's even more confusing.

Karl Dahlke

Re: [Edbrowse-dev] Problem installing git version on debian sid

[Kevin Carhart]

Hi Chuck

I tried out the following, does this help?  Can you bring in the g++ 
compiler:

apt install g++
(and then assuming it puts the compiler under /usr/bin/g++)
export CMAKE_CXX_COMPILER=/usr/bin/g++
(and then build tidy)
(and then apt remove g++ if you like)



On Mon, 4 Dec 2017, Geoff McLane wrote:

> On 04/12/17 20:48, Chuck Hallenbeck wrote:
>> 
>> ... . It says to retrieve 
>> https://github.com/htacg/tidy-html5/archive/master.zip
>
> Yes, as you point out, that certain seems to be the correct 5.6.0 2017.11.25 
> master source, so no problem there...
>
>>
>>   ... The error said the option -c was not recognized by the preprocessor. 
>> .
>
> Well that -c option is one of the most common options - it means compile and 
> assemble but do not link - must be supported by all gcc compilers... in my 
> system $ gcc --version, $ cpp --version, $ c++ --version all appear to be the 
> **same** thing...
>
>
> As stated -
>>> 
>>> I hope others can address that...
>>> 
> I am sure there must be a simple explanation... if it compiles in one, should 
> also in others... keep trying... sure you will get there...
>
> Regards, Geoff.
>
> _______________________________________________
> Edbrowse-dev mailing list
> Edbrowse-dev@lists.the-brannons.com
> http://lists.the-brannons.com/mailman/listinfo/edbrowse-dev
>

--------
Kevin Carhart * 415 225 5306 * The Ten Ninety Nihilists

Re: [Edbrowse-dev] Problem installing git version on debian sid

[Chuck Hallenbeck]

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Hi Kevin,

Well, g++ was already in /usr/bin, but I followed your recommendation 
anyway, and got this:

Script started on 2017-12-04 19:25:38-0500
[archie@debian ~]$ sudo aptitude install g++
 [  0%] Reading package lists                            [100%] Reading package lists                            [  0%] Building dependency tree                               [100%] Building dependency tree                               [  0%] Reading state information                                [ 16%] Reading state information                                [  0%] Reading extended state information                                         [  0%] Initializing package states                                  [  0%] Writing extended state information                                         [  0%] Building tag database                            g++ is already installed at the requested version (4:7.2.0-1d1)
g++ is already installed at the requested version (4:7.2.0-1d1)
No packages will be installed, upgraded, or removed.
0 packages upgraded, 0 newly installed, 0 to remove and 0 not upgraded.
Need to get 0 B of archives. After unpacking 0 B will be used.
 [  0%] Writing extended state information                                         [100%] Writing extended state information                                         [  0%] Reading package lists                            [  0%] Building dependency tree                               [100%] Building dependency tree                               [  0%] Reading state information                                [ 16%] Reading state information                                [  0%] Reading extended state information                                         [  0%] Initializing package states                                  [  0%] Writing extended state information                                         [  0%] Building tag database                            [100%] Building tag database 
[archie@debian ~]$ which g++
/usr/bin/g++
[archie@debian ~]$ cd src/tidy-html5-master/build/cmake/
[archie@debian cmake]$ sudo \b^[[K\b^[[K\b^[[K\b^[[K\b^[[Kexport CMAKE_CXX_COMPILER=/usr/bin/g++
[archie@debian cmake]$ cmake ../..
-- The CXX compiler identification is unknown
-- Check for working CXX compiler: /usr/bin/cpp
-- Check for working CXX compiler: /usr/bin/cpp -- broken
CMake Error at /usr/share/cmake-3.9/Modules/CMakeTestCXXCompiler.cmake:44 (message):
   The C++ compiler "/usr/bin/cpp" is not able to compile a simple test
   program.

   It fails with the following output:

    Change Dir: /home/archie/src/tidy-html5-master/build/cmake/CMakeFiles/CMakeTmp



   Run Build Command:"/usr/bin/make" "cmTC_0f396/fast"

   /usr/bin/make -f CMakeFiles/cmTC_0f396.dir/build.make
   CMakeFiles/cmTC_0f396.dir/build

   make[1]: Entering directory
   '/home/archie/src/tidy-html5-master/build/cmake/CMakeFiles/CMakeTmp'

   Building CXX object CMakeFiles/cmTC_0f396.dir/testCXXCompiler.cxx.o

   /usr/bin/cpp -o CMakeFiles/cmTC_0f396.dir/testCXXCompiler.cxx.o -c
   /home/archie/src/tidy-html5-master/build/cmake/CMakeFiles/CMakeTmp/testCXXCompiler.cxx


   cpp: fatal error: ‘-c’ is not a valid option to the preprocessor

   compilation terminated.

   CMakeFiles/cmTC_0f396.dir/build.make:65: recipe for target
   'CMakeFiles/cmTC_0f396.dir/testCXXCompiler.cxx.o' failed

   make[1]: *** [CMakeFiles/cmTC_0f396.dir/testCXXCompiler.cxx.o] Error 1

   make[1]: Leaving directory
   '/home/archie/src/tidy-html5-master/build/cmake/CMakeFiles/CMakeTmp'

   Makefile:126: recipe for target 'cmTC_0f396/fast' failed

   make: *** [cmTC_0f396/fast] Error 2





   CMake will not be able to correctly generate this project.
Call Stack (most recent call first):
   CMakeLists.txt:26 (project)


-- Configuring incomplete, errors occurred!
See also "/home/archie/src/tidy-html5-master/build/cmake/CMakeFiles/CMakeOutput.log".
See also "/home/archie/src/tidy-html5-master/build/cmake/CMakeFiles/CMakeError.log".
[archie@debian cmake]$ exit

Script done on 2017-12-04 19:34:57-0500


But look at this:

$ g++ --version
g++ (Debian 7.2.0-16) 7.2.0
Copyright (C) 2017 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is 
NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR 
PURPOSE.

Looks like it's there okay, but cmake can't find it.

Chuck








-- 
Here In Northeast Ohio, The Moon is Waning Gibbous (97% of Full)
When your only tool is a hammer, everything looks like a nail.
Sent from Stacy's iPhone.

Re: [Edbrowse-dev] Problem installing git version on debian sid

[Chuck Hallenbeck]

One more fact:

$ cmake --version
cmake version 3.9.5


I'm beginning to appreciate the simplicity of archlinux, where 
everything "just works!"
Chuck


-- 
Here In Northeast Ohio, The Moon is Waning Gibbous (97% of Full)
When your only tool is a hammer, everything looks like a nail.
Sent from Wilbert's iPhone.

Re: [Edbrowse-dev] Problem installing git version on debian sid

[Chris Brannon]

Hi Chuck,
First, you may not even need to build tidy from git.  It may be as easy
as installing tidy5-dev or tidy-dev.  I don't know what package name
they're using on Debian.  If it is tidy-dev, make sure the major version
number is 5, so you don't get the ancient tidy.  If you do need to
install tidy from git, you might be able to do something like:
CXX=g++ cmake
But I'm not sure.  I don't know why cmake is checking for cpp as the C++
compiler.  As Karl says, this is the C preprocessor.  Maybe Debian's
cmake is buggy or misconfigured?
Anyway, if you can get tidy installed with one of those methods, you may
have better luck building edbrowse, which does not use any C++ these
days.

-- Chris

Re: [Edbrowse-dev] Problem installing git version on debian sid

[Chuck Hallenbeck]

On Tue, 5 Dec 2017, Chris Brannon wrote:

> Hi Chuck,

Hi Chris,


> First, you may not even need to build tidy from git.  It may be as easy
> as installing tidy5-dev or tidy-dev.  I don't know what package name
> they're using on Debian.  If it is tidy-dev, make sure the major version
> number is 5, so you don't get the ancient tidy.

Seems like Debian has tidy 5.2.0 installed, but not libtidy-dev.  After 
installing that, I now have /usr/include/tidy/tidy.h present,  but 
compiling edbrowse still says it can't find tidy.h

Where is it looking for it? Can I create a symlink to solve the problem?

Many thanks,

Chuck



-- 
Here In Northeast Ohio, The Moon is Waning Gibbous (94% of Full)
When your only tool is a hammer, everything looks like a nail.
Sent from Nicholas's iPhone.

[Edbrowse-dev] Problem installing git version on debian sid

[Karl Dahlke]

[-- Attachment #1: Type: text/plain, Size: 519 bytes --]

Chuck - you have fallen into a very small window.
There was a brief time where the tidy headers moved into a tidy directory under /usr/local/include; then they moved back.
edbrowse still looks for them at the top.
If you get the latest tidy they are at the top, so I'm not going to change edbrowse proper, it dovetails with the latest tidy,
but if you, in your local copy, insert tidy/ in the various #includes,
#include <tidy/tidy.h>
then type make in the src directory, it should build and run.

Karl Dahlke

Re: [Edbrowse-dev] Problem installing git version on debian sid

[Chuck Hallenbeck]

Hi Karl,

Interesting. I'm assuming that by "latest version" of tidy you mean the 
5.6.0 that Jeff mentioned, and that my Debian environment won't compile.

Well, I already have a "released" edbrowse 3.7.1 on Debian that works, 
and a current devel 3.7.1 on Arch that works, so I might defer further 
fiddling with Debian for the moment.

I can't believe g++ is broken on Debian Sid, but I haven't got any c++ 
sources handy to check that. I have a bunch of my own stuff in plain C, 
and they still compile fine, but no c++ sources to use for testing.

Thanks for your help.

Chuck

-- 
Here In Northeast Ohio, The Moon is Waning Gibbous (94% of Full)
When your only tool is a hammer, everything looks like a nail.
Sent from Norma's iPhone.

Re: [Edbrowse-dev] Problem installing git version on debian sid

[Geoff McLane]

Hi all,

Sorry for the problems here, at least as far as HTML Tidy is concerned...

1. Yes, for some period recently, tidy.h was being installed in a 
sub-directory,
'tidy'... That is into /usr/include/tidy/, or /usr/local/include/tidy/...
However the FindTidy.cmake also accounted for this... But this has been
**fixed** in the latest 5.6

The cmake default is /usr/local/include unless you add the cmake option -
$ cmake ../.. -DCMAKE_INSTALL_PREFIX=/usr -DCMAKE_BUILD_TYPE=Release

The second option is to ensure you are building the 'release' library. Some
cmake versions default to 'debug' unless this is specified...

But where ever it got installed to, you should be able to add -
$ export TIDY_ROOT=/path/to/tidy/install
when doing the edbrowse $ cmake .. [options]

Or even add it as a cmake option, -DTIDY_ROOT=/path/to/tidy/install

The CMakeFiles/FindTidy.cmake I supplied supports using this 'TIDY_ROOT'
define... either in environment or as an option...

This is so people like me, or Karl, and others, can build even later
versions of Tidy, and install them local to the build for testing edbrowse
with that version without disturbing the global release install of Tidy...

2. Yes, it takes time, too long in my book, for the latest tidy releases 
to show
up in distributions. And my searching showed Debian is still back at 5.2 
release.
There has been a 5.4 and now a 5.6 release since then...

And AFAIK Tidy has never been separated into 'tidy' and 'tidy-dev' 
packages, but
that would not stop some distributions doing that... in most cases the 
needed
headers and libraries were included in the quite small 'tidy' package...

3. Not sure I agree cpp/c++ are preprocessors packages... running either of
them with --help shows -c is a valid option, but maybe that is beside the
point...

As I first stated tidy is also a pure C package, and adding that to the
CMakeLists.txt, like project(tidy C) will tell cmake to not look for
a cpp/c++ compiler... and should allow latest 5.6 tidy to be built, and
installed... from the zip, or repo...

And likewise for edbrowse CMakeLists.txt, like project (edbrowse C),
if edbrowse also only uses C...

And I too can not understand why g++/cpp/c++ would be broken in
Debian sid... That is a real puzzle... but as stated not required
for tidy, nor edbrowse... just change the project (...) lines...

HTH, Geoff.

Re: [Edbrowse-dev] Problem installing git version on debian sid

[Chuck Hallenbeck]

On Tue, 5 Dec 2017, Geoff McLane wrote:

> Hi all,

Hi Jeff,

>
> Sorry for the problems here, at least as far as HTML Tidy is concerned...
>
> 1. Yes, for some period recently, tidy.h was being installed in a 
> sub-directory,
> 'tidy'... That is into /usr/include/tidy/, or /usr/local/include/tidy/...
> However the FindTidy.cmake also accounted for this... But this has been
> **fixed** in the latest 5.6
>
> The cmake default is /usr/local/include unless you add the cmake option -
> $ cmake ../.. -DCMAKE_INSTALL_PREFIX=/usr -DCMAKE_BUILD_TYPE=Release
>
> The second option is to ensure you are building the 'release' library. Some
> cmake versions default to 'debug' unless this is specified...
>

I refreshed my download of tidy 5.6.0, and tried compiling it using your 
suggested options (cutting and pasting), with the same result. "the 
option -c is invalid in cpp" etc., etc.

Bummer.


> But where ever it got installed to, you should be able to add -
> $ export TIDY_ROOT=/path/to/tidy/install
> when doing the edbrowse $ cmake .. [options]
>
> Or even add it as a cmake option, -DTIDY_ROOT=/path/to/tidy/install
>
> The CMakeFiles/FindTidy.cmake I supplied supports using this 'TIDY_ROOT'
> define... either in environment or as an option...
>
> This is so people like me, or Karl, and others, can build even later
> versions of Tidy, and install them local to the build for testing edbrowse
> with that version without disturbing the global release install of Tidy...
>
> 2. Yes, it takes time, too long in my book, for the latest tidy releases to 
> show
> up in distributions. And my searching showed Debian is still back at 5.2 
> release.
> There has been a 5.4 and now a 5.6 release since then...
>
> And AFAIK Tidy has never been separated into 'tidy' and 'tidy-dev' packages, 
> but
> that would not stop some distributions doing that... in most cases the needed
> headers and libraries were included in the quite small 'tidy' package...
>
> 3. Not sure I agree cpp/c++ are preprocessors packages... running either of
> them with --help shows -c is a valid option, but maybe that is beside the
> point...
>
> As I first stated tidy is also a pure C package, and adding that to the
> CMakeLists.txt, like project(tidy C) will tell cmake to not look for
> a cpp/c++ compiler... and should allow latest 5.6 tidy to be built, and
> installed... from the zip, or repo...
>
> And likewise for edbrowse CMakeLists.txt, like project (edbrowse C),
> if edbrowse also only uses C...
>
> And I too can not understand why g++/cpp/c++ would be broken in
> Debian sid... That is a real puzzle... but as stated not required
> for tidy, nor edbrowse... just change the project (...) lines...
>
> HTH, Geoff.
>

-- 
Here In Northeast Ohio, The Moon is Waning Gibbous (93% of Full)
When your only tool is a hammer, everything looks like a nail.
Sent from Emil's iPhone.

[Edbrowse-dev] what is dispatchEvent and is it needed?

[Kevin Carhart]

Since we started talking about events, I felt like I needed to reacclimate 
myself with whether there is a point to some of these functions with Event 
in their name. 
Currently the first occurring runtime error in one of the sites we're 
testing on, xqsuperschool.org, involves dispatchEvent.  But what does it 
do?  I looked it up and found out.  The flavor of why dispatchEvent is 
used is a little like calling raise() in code.  It's like you're 
simulating something.  So the role for dispatchEvent would be if 
you want to call an event handler from elsewhere in the code.  If there is 
a button1 with a handler on click, the users might click the button and 
the handler code would run.  But if you want to trigger that code and you 
want to do it "the right way", you do it via interacting with that 
element.  So you call dispatchEvent(button,"click") and you have done just 
what your user would have.  An MDN page says "Such events are commonly called 
synthetic events, as opposed to the events fired by the browser itself."

It reminds me of OO.  You're reaching the handler code by addressing it 
through a published way of reaching it.  It reminds me of public and 
private members, and that type of flavor.

I suppose it would come up in the context of testing.  Also in the 
edbrowse code itself we have had situations where, I don't know, you're 
writing one DOM method, and you call another DOM method from within that, 
because it's already been tested and is as good a solution as revisiting 
the lower level stuff.

So based on this information, I think dispatchEvent is good solid 
functionality and once I get it together, I'll send some code.

Kevin

[Edbrowse-dev] what is dispatchEvent and is it needed?

[Karl Dahlke]

> dispatchEvent(button,"click")

At first glance this seems silly, as one can call button.onclick() to run that function,
this was part of javascript since day one, but dispatchEvent probably does something more, it probably bubbles up.
So we would need to march up the tree via parentNode and call any onclick functions along the way.
Rather like handlerGoBrowse in C, but a js version, which isn't hard at all.

Karl Dahlke

Re: [Edbrowse-dev] what is dispatchEvent and is it needed?

[Kevin Carhart]

On Sun, 10 Dec 2017, Karl Dahlke wrote:

>> dispatchEvent(button,"click")
>
> At first glance this seems silly, as one can call button.onclick() to run that function,

Yes.. there must be some reason.  Well, it's parameterized, right?
Maybe easier to use with something like

for each element in (a b c d)
for each event in (click blah blah2 blah3)

I dunno.