Interface IAnalysisObserver
Receives the facts that the runtime semantics state about the code they evaluate: the conversions it asks for, the operations it performs, what its statements do, and the run-time errors it raises.
public interface IAnalysisObserverRemarks
An observer is attached to a runtime pipeline when the pipeline is composed, and sees every conversion, operation and statement that pipeline evaluates, at the point where the evaluation would call the semantics. That is what makes what is observed the language's own answer, rather than a second walk of the code that must be kept in step with the first.
A pipeline composed without an observer states no facts and behaves exactly as before: observation costs a null check. An observer must not throw, and must not call back into the pipeline that is calling it.
A pipeline and its observer belong to one analysis: an observer is not required to be thread-safe.
Methods
OnConversion(ConversionFact)
A value was let-coerced (MS-VBAL 5.5.1.2).
void OnConversion(ConversionFact fact)Parameters
factConversionFactWhat the conversion is, and what is known of it.
OnError(VBErrorInfo)
An instruction raised a run-time error that is the code's: it raises it whenever it runs.
void OnError(VBErrorInfo error)Parameters
errorVBErrorInfoThe error, where the instruction raises it.
Remarks
👉 The error an evaluation raises for a value it only assumed is never one: the runtime semantics do not raise it. Nor is an internal error, which is a defect of the platform and not something the code does.
OnOperation(OperatorFact)
An operator was evaluated (MS-VBAL 5.6.9), or a member was accessed (MS-VBAL 5.6.12-14).
void OnOperation(OperatorFact fact)Parameters
factOperatorFactWhat the operation is, and what is known of it.
OnStatement(StatementFact)
A statement whose runtime semantics establish facts of their own was evaluated (MS-VBAL 5.4).
void OnStatement(StatementFact fact)Parameters
factStatementFactWhat the statement does, and what is known of it.