Standard naming for variables with files, directories and paths

I suggest to use the following approach in the naming:

• filename - file name: readme.txt
• dirname - directory name: mydir
• filepath - file name, including any path to it: path/to/readme.txt
• dirpath - directory name, including any path to it: path/to/mydir

As for the words file and dir themselves, I'd recommend not using them for paths at all, because:

• file is a good name for storing file objects.
• dir can be used for DirEntry objects of readdir/opendir etc.

However, since the latter usage is not very common, to save typing dir can also be used as an alias for the a dirname based variable in a local context.

Examples

Suppose we have a baz project directory with a readme.txt file.

Then we could define the following variables:

camelCase	snake_case	path/to/baz/readme.txt
readmeFilename	readme_filename	readme.txt
readmeFilepath	readme_filepath	path/to/baz/readme.txt
readmeDirname	readme_dirname	baz/
readmeDirpath	readme_dirpath	path/to/baz/
projectDirname	project_dirname	baz/
projectDirpath	project_dirpath	path/to/baz/

NOTE: The slash character after directories above is optional.