8  Script Variables

In the name example above, our project is going to carry on an interaction with the user, and we want to remember their name throughout the project. That’s a good example of a situation in which a global variable (the kind you make with the “Make a variable” button) is appropriate. Another common example is a variable called “score” in a game project. But sometimes you only need a variable temporarily, during the running of a particular script. In that case you can use the script variables block to make the variable:

As in the for block, you can click on an orange oval in the script variables block without dragging to change its name. You can also make more than one temporary variable by clicking on the right arrow at the end of the block to add another variable oval:

8.1 Renaming variables

There are several reasons why you might want to change the name of a variable:

  1. It has a default name, such as the “a” in script variables or the “i” in for.

  2. It conflicts with another name, such as a global variable, that you want to use in the same script.

  3. You just decide a different name would be more self-documenting.

In the first and third case, you probably want to change the name everywhere it appears in that script, or even in all scripts. In the second case, if you’ve already used both variables in the script before realizing that they have the same name, you’ll want to look at each instance separately to decide which ones to rename. Both of these operations are possible by right-clicking or control-clicking on a variable oval.

If you right-click on an orange oval in a context in which the variable is used, then you are able to rename just that one orange oval:

If you right-click on the place where the variable is defined (a script variables block, the orange oval for a global variable in the Variables palette, or an orange oval that’s built into a block such as the “i” in for), then you are given two renaming options, “rename” and “rename all.” If you choose “rename,” then the name is changed only in that one orange oval, as in the previous case:

But if you choose “rename all,” then the name will be changed throughout the scope of the variable (the script for a script variable, or everywhere for a global variable):