Duration

5 minutes

Lab Goals

The primary goal of this lab will be to interact with the REPL (Read-Evaluate-Print-Loop) and experiement with assigning values and printing strings.

Tip: If you are doing this exercise live in a session, make sure to make good use of the instructor, they are online to answer any questions you have!

Steps

Setup

Open Visual Studio.
Open the REPL window in your IDE
- Visual Studio for Mac - View > Pads > F# Interactive
- Visual Studio on Windows - View > F# Interactive

Assigning Values

Enter the following into your REPL (remember to use a double-semicolon to terminate the REPL input in the window). What happens? You can check out all the format specifiers for printfn on MSDN.
```
printfn "hello world";;
```
Next, enter the following statement into your REPL. What happens?
```
let x = 42;;
```
Try to change value you just assigned. Does it work? Was that value immutable?
```
let x = 10;;
```

Summary

In this lab, we have opened the REPL and begun to interact with it.

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