Marin Lagacé - Coding

Qt Translation: Qualifying with unknown namespace/class

2020-12-05T14:49:00-05:00

I was translating a widget library written in Qt when I got the following error.

[ 44%] Generating foo_fr.ts
Bar.cpp:40: Qualifying with unknown namespace/class ::Bar
Updating 'foo_fr.ts'...
    Found 3 source text(s) (3 new and 0 already existing)

I could not find a lot of info about this error on the internet. Luckily, I ran across this post on StackOverflow that guided me toward a solution.

The problem came from the way the library was designed. Its public header files are not in the same directory as its implementation files.

Foo
|-- include
|   '-- foo
|       '-- Bar.hpp
+-- src
|   |-- Bar.cpp
|   +-- CMakeLists.txt
+-- CMakeLists.txt

This poses a problem because Qt's translation utilities expect the header files to be in the same directory as their implementation files. In case they are not, one must specify their directory when calling lupdate. Since the library I was translating uses CMake as its build tool, this is done using the qt5_create_translation macro and adding the -I flag with the header files path to the OPTIONS parameter.

# Foo/src/CMakeLists.txt
qt5_create_translation(QM_FILES
    Bar.cpp
    foo_fr.ts
    OPTIONS -I ${CMAKE_CURRENT_SOURCE_DIR}/../include
)

Portable Vim on Windows

2020-12-01T21:36:00-05:00

When doing Windows development, I usually use Vim under Cygwin. I use my little Cygwin hack to make it portable. This allows me to easily copy my Cygwin installation along with all my settings to multiple computer.

I rely heavily on Fugitive which is a great Vim plugin for Git. Unfortunately, it runs extremely slowly on my main work computer. So, on that computer, I use gVim Portable from the PortableApps platform. It works great. The tricky part is making it work along with Git (for Fugitive) and Python (for UltiSnips). It involves installing Git along with the proper version of Python and tweaking a configuration file of gVim Portable.

Installing Portable Git

Download it from their website. Make sure to download the portable version.

Then, install it alongside of gVim.

e:
├── gVimPortable
│   ├── App
│   ├── ...
│   ├── gVimPortable.exe
│   └── ...
└── PortableGit
    ├── bin
    ├── ...
    ├── git-bash.exe
    ├── git-cmd.exe
    └── ...

Installing Python

It is important to install the appropriate version of Python. It needs to be a Python 3 version because UltiSnips does not support Python 2 anymore. Furthermore, it needs to be the Python version expected by Vim. See my previous article on installing Ultisnips on Cygwin for a description of the technique to use to find out which Python version your installation of Vim expects to find on your system.

As of this writing, gVim Portable needs Python 3.6. Furthermore, gVim Portable was compiled for 32-bit systems.

So the portable x86 version should be used.

As for Git, install it alongside gVim.

e:
├── gVimPortable
│   ├── ...
│   ├── gVimPortable.exe
│   └── ...
├── PortableGit
│   ├── ...
│   ├── git-bash.exe
│   ├── git-cmd.exe
│   └── ...
└── Python36-x86
    ├── ...
    ├── python.exe
    ├── ...
    ├── python36.dll
    └── ...

Configuring gVim Portable

We must now tell gVim where to find our intallations of Git and Python. For that, we must edit the gVimPortable.ini file located deep into the directory structure.

e:
└── gVimPortable
    └── App
        └── AppData
            └── Launcher
                └── gVimPortable.ini

Add the PYTHON_HOME and GIT_HOME variable definitions to the [Environment] section of the file.

[Environment]
VIM=%PAL:AppDir%\vim
VIMRUNTIME=%PAL:AppDir%\vim\vim80
HOME=%PAL:DataDir%\settings
LANG=%PAL:LanguageCustom%
PYTHON_HOME=%PAL:PortableAppsDir%\Python36-x86
GIT_HOME=%PAL:PortableAppsDir%\PortableGit

Finally, modify the PATH variable in your .vimrc file to add the path to your Git and Python installation.

if !empty($PYTHON_HOME)
  let $PATH .= ';' . $PYTHON_HOME . ';' . $PYTHON_HOME . '\scripts'
  let $PYTHONHOME = $PYTHON_HOME
endif
if !empty($GIT_HOME)
  let $PATH .= ';' . $GIT_HOME . '\bin'
endif

After this, Fugitive and Ultisnips should work fine when editing files in your gvim installation.

UltiSnips on Cygwin

2020-06-27T10:01:00-04:00

UltiSnips is the plugin for Vim that I use the most. It allows for the creation of macros (named snippets) that insert predefined chuncks of text at the desired location in a file. These snippets automate the insertion of repetitive lines of code. They can be very simple like the following one which write the necessary C++ code to print text to the console:

They can be much more complex like this one which creates the header for a C++ class:

UltiSnips requires Python3 to run. Thus, Vim must have been compiled with Python3 support. To check, start Vim with the --version argument.

Fortunately, this is the case for the version of Vim found in the Cygwin repo.

It is not enough to have installed Python for UltiSnips to work out of the box. We need to have installed the same version that Vim was compiled for. To check that the link between Vim and Python works proprely, we can simply try to run any Python expression in Vim using the :python3 command. ¹

If the Vim/Python link is correct, the command will be executed without any error. Otherwise, an error message will be displayed at the bottom of the window.

We see here that Vim is looking for Python 3.7. We just need to start the Cygwin installation app and install the python37 package.

Once installed, UltiSnips should properly work.

UltiSnips does not support Python2 since commit d2f42d6. It is thus important to use the :python3 command for our test. ↩

FileBeagle

2020-05-31T19:50:00-04:00

Vim has netrw as a built-in directory browser. It is pretty basic and some people like that. Others find it a bit too basic or unintuitive. Tim Pope wrote vinegar to "enhance netrw, partially in an attempt to mitigate the need for more disruptive 'project drawer' style plugins". ¹

A very popular tree explorer plugin is NERDTree. It is very pretty and has a lot of features but I find it a little too heavy for my taste.

I prefer to use FileBeagle as my directory browser. It is simple and efficient. As stated by its developer:

Vim is a text editor, not an operating system that can edit text. FileBeagle respects this, and attempts to conform to this both in spirit and in practice. If you are looking for a plugin to serve as a filesystem manager from within Vim, FileBeagle is not it. FileBeagle does not support copying, deleting, moving/renaming, or any other filesystem operations. FileBeagle lists and opens files. ²

The - key is mapped to open FileBeagle on the directory of the current buffer. You can then use the standard Vim navigation keys to move to a file or a directory or press - to go to the parent directory. Pressing Enter will either go into the selected directory or open the selected file for editing. There are many more functions available. I refer you to the plugin's documentation for more info.

I like FileBeagle to display hidden files and relative line numbers. Here are the variables I set in my .vimrc file to accomplish that.

let filebeagle_show_hidden=1
let filebeagle_show_line_numbers=1
let filebeagle_show_line_relativenumbers=0

Give FileBeagle a try. You might like it.