switch statement cleanup

[nate-thegrate]

This PR is step 12 in the journey to solve issue #136139 and make the entire Flutter repo more readable.

Most of it involves implementing switch expressions, and there's also a few other random things that I wanted to clean up a bit.

[victorsanni]

Hi @nate-thegrate! I've left a couple comments, and once addressed I will go ahead and approve. Thanks for the work!

[victorsanni]

I am confused as to how GalleryDemoCategory.study becomes just study (same for the other values of GalleryDemoCategory. I can't find where these variables were assigned.

[nate-thegrate]

When you're inside a class declaration, you can use its static members without needing to type out the class name:

classMyClass {
staticconst value =42;
voidfoo() {
print(MyClass.value); // you can use the class name, but it's not necessaryprint(value); // it works!
}
}
voidfoo() {
print(MyClass.value); // name is required outside the class
}

An enum declaration works the same way:

enumMyEnum {
a,
b,
c;
voidfoo() {
print('$a $b $c');
}
}
voidfoo() {
print('${MyEnum.a} ${MyEnum.b} ${MyEnum.c}');
}

[victorsanni]

Ah, I did not know this was possible. Thanks for enlightening me.

[victorsanni]

Is the variable conditionName still necessary?

[nate-thegrate]

Nope! I just have it here because of the line length guideline:

WaitConditiondeserializeCondition(SerializableWaitCondition waitCondition) {
returnswitch (waitCondition.conditionName) {
// ...finalString conditionName =>throwSerializationException('Unsupported wait condition $conditionName in ${waitCondition.serialize()}'),
};

Defining the variable beforehand lets us use a _ instead.

[nate-thegrate]

+301 -529 is a lot of diffs to go through—thanks for the review and for your attention to detail!

[nate-thegrate]

When you're inside a class declaration, you can use its static members without needing to type out the class name:

classMyClass {
staticconst value =42;
voidfoo() {
print(MyClass.value); // you can use the class name, but it's not necessaryprint(value); // it works!
}
}
voidfoo() {
print(MyClass.value); // name is required outside the class
}

An enum declaration works the same way:

enumMyEnum {
a,
b,
c;
voidfoo() {
print('$a $b $c');
}
}
voidfoo() {
print('${MyEnum.a} ${MyEnum.b} ${MyEnum.c}');
}

[nate-thegrate]

Nope! I just have it here because of the line length guideline:

WaitConditiondeserializeCondition(SerializableWaitCondition waitCondition) {
returnswitch (waitCondition.conditionName) {
// ...finalString conditionName =>throwSerializationException('Unsupported wait condition $conditionName in ${waitCondition.serialize()}'),
};

Defining the variable beforehand lets us use a _ instead.