初めての.mojoファイル

Mojo programs live in plain text files. Each one ends with the .mojo extension so the toolchain knows how to compile and run it. 📄

Pick a short, lowercase name like hello.mojo. A clear file name makes it obvious what the program does when you come back later.

Mojo even allows the fire emoji as an extension, so hello.🔥 is valid too. Most people stick with .mojo for everyday work though.

The classic first program prints a greeting. In Mojo you use print, just like Python, to send text to the screen.

Your runnable code belongs in a function called main. Mojo looks for it as the starting point when the file runs.

Like Python, Mojo uses indentation to group code. The print line is indented under main, showing it belongs to that function.

Type the code in your editor and save it as hello.mojo. Nothing runs until you save, so this step matters before you try it.

The text inside the quotes is yours to edit. Swap it for a string like your name to make the program feel like your own.

Any text you print must sit inside quotes. Without them Mojo treats the words as code and reports an error instead of printing.

This single .mojo file is a complete program. It has a main function with one job: greeting you. Small, but truly real Mojo.

With hello.mojo saved, you have everything needed to run it. The next lessons show how to launch it from the command line.

You just created your first source file. What is the standard extension for a Mojo program?

You made a .mojo file, put a print call inside main, and saved it. That single file is a complete, ready-to-run Mojo program. 🎯