Alda comes with an interactive REPL (Read-Eval-Play Loop) that you can use to play around with its syntax. After each line of code that you enter into the REPL prompt, you will hear the result.
To start the Alda REPL, run:
alda repl
At the REPL prompt, you can either enter Alda code, or use one of the available built-in commands, which start with a colon.
For a list of available commands, enter :help.