feature: Spoon metamodel

[pvojtechovsky]

Requirements:

• annotations on metamodel properties (@Unsettable, @DerivedProperty @PropertyGetter or @PropertySetter) see review feat(role): field annotation with a role #1368
• get list of metamodel classes (should be moved from test code to main code) see feature: add first metamodel support #1378

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Some code in spoon library is generated by generators. Do we have in spoon an metamodel, which can be used as good input for future generators?

Idea: if we would have a good and complete metamodel of spoon model, then this metamodel might be used to generate more sources and to implement issues like #741, #1168 faster.

If I understood it well current spoon generators are using CtScanner and annotations on spoon model interfaces as source metamodel. May be we might write a code which scans current spoon sources, mainly

• class CtScanner,
• package: spoon.reflect.code
• package: spoon.reflect.declaration
• package: spoon.reflect.reference
  and to automatically build a real - easy to use :-) ... metamodel, which might be then used as input of next generation generators and may be might be even used to update spoon model itself.

... I know, it is quite big task, but may be once ...

[monperrus]

To some extent, creating the Spoon of model of spoon.reflect.declaration/code is the spoon metamodel itself, and this is what's done for generating classes and testing the metamodel itself.

If I understood it well current spoon generators are using CtScanner and annotations on spoon model interfaces as source metamodel

Correct

Moving this information elsewhere make it more explicit but is one more level of indirection to understand and maintain.

[pvojtechovsky]

I understand what you mean and I agree.

I am thinking, how to minimize amount of manually written code and replace it by generated code. May be the spoon sources (even one file) might contain both manually written and generated code. The generated code would be marked (e.g by some comment) and the generator would be allowed to update only such sections. For example the sources file below contains both manually written and generated code:

public class CtBreakImpl extends CtStatementImpl implements CtBreak {
	private static final long serialVersionUID = 1L;

//begin of code genereated by: ModelGeneratorTemplate#primitiveProperty
	String targetLabel;
//end of genereated code

//begin of code genereated by: ModelGeneratorTemplate#visitorPattern_accept
	@Override
	public void accept(CtVisitor visitor) {
		visitor.visitCtBreak(this);
	}
//end of genereated code

//begin of code genereated by: ModelGeneratorTemplate#primitiveGetter
	@Override
	public String getTargetLabel() {
		return targetLabel;
	}
//end of genereated code

//begin of code genereated by: ModelGeneratorTemplate#primitiveSetter
	@Override
	public <T extends CtBreak> T setTargetLabel(String targetLabel) {
		this.targetLabel = targetLabel;
		return (T) this;
	}
//end of genereated code

//begin of code genereated by: ModelGeneratorTemplate#clone
	@Override
	public CtBreak clone() {
		return (CtBreak) super.clone();
	}
//end of genereated code
}

Such sources would allow mixing of manually written code and generated code. The generator must of course assure that manually written code is not lost during update of generated code.
It would let us to apply design patterns on spoon sources and to implement new features, which needs the same change in each property setter consistently, with lower effort, less mistakes and lower maintenance - because the code is generated and not manually written.

[monperrus]

I am thinking, how to minimize amount of manually written code and replace it by generated code.

Interesting. This is already what we have in Spoon for replacement and equality code.

May be the spoon sources (even one file) might contain both manually written and generated code

This is possible, but I need a longer answer to explain. More on this later.

[monperrus]

Considered closed per the recent work on annotations for roles.