How to use the command 'racket' (with examples)
The racket command is the Racket language interpreter. It allows you to run Racket scripts, execute Racket expressions, start an interactive shell (REPL), and more.
Use case 1: Start a REPL (interactive shell)
Code:
racket
Motivation: Starting a REPL allows you to interactively execute Racket code. This is useful for experimentations, debugging, and learning the Racket language.
Explanation:
Running the racket command without any arguments launches the Racket REPL, where you can enter Racket expressions and see their results in real-time.
Example output:
Welcome to Racket v7.9 [cs].
->
Use case 2: Execute a Racket script
Code:
racket path/to/script.rkt
Motivation: Executing a Racket script allows you to run a predefined set of Racket code stored in a file. This is useful for running larger programs or scripts.
Explanation:
The racket command followed by the file path to a Racket script executes the script using the Racket interpreter.
Example output:
[output of the script]
Use case 3: Execute a Racket expression
Code:
racket --eval "expression"
Motivation: Executing a Racket expression directly from the command line allows you to quickly test code snippets or evaluate small pieces of Racket code without needing to create a separate script.
Explanation:
The --eval option followed by a Racket expression enclosed in double quotes instructs the Racket interpreter to evaluate the expression and display the result.
Example output:
[output of the expression]
Use case 4: Run module as a script (terminates option list)
Code:
racket --lib module_name --main arguments
Motivation: Running a module as a script allows you to execute a Racket module directly as a standalone program.
Explanation:
The --lib option followed by the module name specifies the Racket module to be run. The --main option followed by arguments passes the specified arguments to the main function defined within the module.
Example output:
[output of the module execution]
Use case 5: Start a REPL (interactive shell) for the typed/racket hashlang
Code:
racket -I typed/racket
Motivation:
Starting a REPL for the typed/racket hashlang allows you to interactively write and test typed Racket code. The typed/racket variant of Racket provides static type-checking capabilities.
Explanation:
The -I option followed by typed/racket executes the Racket interpreter with the typed/racket language variant, enabling type-checking features in the REPL.
Example output:
Welcome to Racket v7.9 [cs].
->
Conclusion:
The racket command provides a powerful and flexible way to interact with the Racket language. From starting a REPL to executing scripts and expressions, the various use cases of the racket command allow you to write, test, and run Racket code efficiently and effectively.
