kristianka / days_cpp_old

Days utility in C++20

Days

Days is a UNIX-style utility for reporting about events and their relation to the current date. It shows both past and future events with a count of days since or until an event.

The events have a date, a category and a description. They are stored in a CSV file called events.csv in a subdirectory called .days inside the user's home directory.

Days can also congratulate the user on their birthday if the current date is the same as their birthdate, set as an enviroment variable called BIRTHDATE, with the value in YYYY-MM-DD format, for example, 1988-08-16.

The event file

The program reads the events to display from a CSV file. Create the ~/.days directory if it doesn't already exist. Add a file called events.csv inside that directory, with contents in the following format:

2020-12-15,computing,C++20 released
2023-01-10,computing,Rust 1.66.1 released
2022-09-20,computing,Java SE 19 released
2014-11-12,computing,.NET Core released

The format of each line should be date,category,description in the CSV (comma-separated value) style. Here date is the date in ISO 8601 standard format YYYY-MM-DD, while category and description are free text.

Ideally, category is a single word like history, personal or computing, but there are no predefined categories.

NOTE: If your description contains commas, you will need to put it in quotation marks, because otherwise the commas would mess up the CSV parsing. For example, a line with a description containing commas could be:

2010-02-14,personal,"Signed, sealed, and delivered"

Compiling the program

Days is written in C++20, so you will need a C++ compiler that supports that standard.

Windows

In Microsoft Windows the use of the Microsoft C/C++ Compiler is preferred. If you have Visual Studio installed, and have also installed the "Desktop Development with C/C++" workload, you have the necessary tools installed. Open "Developer Command Prompt for Microsoft Visual Studio 2022" (or whatever version you have, like 2019) from the Start menu, navigate to the directory where you cloned this repository, and use the command

cl /std:c++20 /EHsc days.cpp event.cpp

to compile the program. The result is an executable file called days.exe, which you can run with the command days in the Command Prompt.

macOS

In macOS you can use either the clang compiler installed with Xcode, or the GNU C/C++ compiler installed with Homebrew. For example, if you have Xcode installed, you should be able to compile the program with

clang++ -std=c++20 -o days days.cpp event.cpp

which produces an executable file called days. Run the program with ./days (the ./ prefix is needed because you should never have the current directory in your PATH).

Linux

In a standard Linux environment you probably already have development tools installed, so you should be able to compile the program using the GNU C++ compiler:

g++ -std=c++20 -o days days.cpp event.cpp

which produces an executable file called days. Run the program with ./days (the ./ prefix is needed because you should never have the current directory in your PATH).

Please use at least GCC 11 to enjoy the C++20 features. Note that you might need to update your distro to a newer version, eg. WSL2 Ubuntu users need to update from 20.04 to 22.04 so they you can use GCC 11. Instructions how to update are here.

The BIRTHDATE environment variable

If the program environment contains the BIRTHDATE variable, and its value is a date in the YYYY-MM-DD format, this application will use the value to show a birthday greeting to the user.

If you are a Linux user, you should set the BIRTHDATE environment variable in your .bashrc file (or ~/.bash_profile, or ~/.profile, or whatever your shell uses).

Windows users need to open the old style Control Panel, then navigate to System Properties, Advanced, Environment Variables. Set a user variable, not a system variable.

Note that changes to environment variables will not be picked up by a running shell. After you have defined the environment variable, close the shell window, then open it again.