Struct RuntimeSemanticsEvaluationResult<TValue>

Namespace

RDCore.SDK.Runtime.Shared

Assembly

RDCore.SDK.dll

Represents the result of an evaluation whose result type is known statically: the same outcome as RuntimeSemanticsEvaluationResult, with the VBTypedValue it produces named by TValue.

public readonly record struct RuntimeSemanticsEvaluationResult<TValue> : IRuntimeSemanticsEvaluationResult, IEquatable<RuntimeSemanticsEvaluationResult<TValue>> where TValue : VBTypedValue

Type Parameters

TValue

The VBTypedValue a successful evaluation produces.

Implements

IRuntimeSemanticsEvaluationResult

IEquatable<RuntimeSemanticsEvaluationResult<TValue>>

Inherited Members

ValueType.Equals(object)

ValueType.GetHashCode()

ValueType.ToString()

object.Equals(object, object)

object.GetType()

object.ReferenceEquals(object, object)

Remarks

This is how a standard-library member declaration states its VBA return type (RD-VBAL §6.1: "the symbols shall carry the appropriate return type metadata"). Naming it in the signature rather than restating it in an attribute means the declaration and the implementation cannot disagree - an implementation of Hex$ that returns anything but a VBStringValue does not compile - and a symbol provider reads the declared type back off the signature.

A member returning nothing - a VBA Sub, or a Property Let/Set - is declared with the non-generic RuntimeSemanticsEvaluationResult instead, so the presence of a return type is itself part of the declaration. Its declared type is VBVoidType and the value it yields is Void - not VBEmptyValue, which is a real Variant subtype source can see (IsEmpty, VarType, a Let-coercion to 0); the result of a Sub is nothing source can see anything about at all.

👉 An enumeration or a class is not expressible as a TValue: every value of one is a VBLongValue or a VBObjectValue respectively, which is what an implementation produces and so what this names. Those members state the type VBA source sees with ReturnType.

Constructors

RuntimeSemanticsEvaluationResult(TValue?, IVBRaisableError?)

Represents the result of an evaluation whose result type is known statically: the same outcome as RuntimeSemanticsEvaluationResult, with the VBTypedValue it produces named by TValue.

public RuntimeSemanticsEvaluationResult(TValue? Result, IVBRaisableError? ErrorInfo)

Parameters

Result TValue

The result of the evaluation, if one was produced.

ErrorInfo IVBRaisableError

The error metadata for the run-time error to be reported, if applicable.

Remarks

This is how a standard-library member declaration states its VBA return type (RD-VBAL §6.1: "the symbols shall carry the appropriate return type metadata"). Naming it in the signature rather than restating it in an attribute means the declaration and the implementation cannot disagree - an implementation of Hex$ that returns anything but a VBStringValue does not compile - and a symbol provider reads the declared type back off the signature.

A member returning nothing - a VBA Sub, or a Property Let/Set - is declared with the non-generic RuntimeSemanticsEvaluationResult instead, so the presence of a return type is itself part of the declaration. Its declared type is VBVoidType and the value it yields is Void - not VBEmptyValue, which is a real Variant subtype source can see (IsEmpty, VarType, a Let-coercion to 0); the result of a Sub is nothing source can see anything about at all.

👉 An enumeration or a class is not expressible as a TValue: every value of one is a VBLongValue or a VBObjectValue respectively, which is what an implementation produces and so what this names. Those members state the type VBA source sees with ReturnType.

Properties

ErrorInfo

The error metadata for the run-time error to be reported, if applicable.

public IVBRaisableError? ErrorInfo { get; init; }

Property Value

IVBRaisableError

IsError

true if the evaluation semantically yields a runtime error.

public bool IsError { get; }

Property Value

bool

Remarks

👉 This value represents a specified, consistent state where program execution resumes in a controlled error state.
A result value may or may not have been assigned before the failure: most errors carry none, which is why this asks only whether there is an error. It used to require a value too, and so answered false for every error raised without one - which is what Error(VBRuntimeErrorInfo, VBTypedValue?)'s own default produces.

IsInternalError

true if an evaluation strategy could not be determined.

public bool IsInternalError { get; }

Property Value

bool

Remarks

⚠️ This value represents an unspecified, inconsistent internal state that is ultimately surfaced as an InternalError run-time error.

IsSuccess

true if the evaluation was successfully completed.

public bool IsSuccess { get; }

Property Value

bool

Remarks

✅ This value represents a normally completed, successful evaluation.

Result

The result of the evaluation, if one was produced.

public TValue? Result { get; init; }

Property Value

TValue

Methods

Error(IVBRaisableError, TValue?)

Creates a new (failed) RuntimeSemanticsEvaluationResult with the specified IVBRaisableError error information metadata.

public static RuntimeSemanticsEvaluationResult<TValue> Error(IVBRaisableError error, TValue? result = null)

Parameters

error IVBRaisableError

The runtime error metadata describing the evaluation failure.

result TValue

The result value assigned before the failure, if any.

Returns

RuntimeSemanticsEvaluationResult<TValue>

Remarks

❌ Use this method only to signal a failed expression evaluation. A result value may still have been assigned.

InternalError()

Creates a new RuntimeSemanticsEvalutationResult without a result, and without any IVBRaisableError error metadata.

public static RuntimeSemanticsEvaluationResult<TValue> InternalError()

Returns

RuntimeSemanticsEvaluationResult<TValue>

Remarks

💥 This results signals a InternalError run-time error to the evaluation pipeline. Use it only as a fallback result, when no result can be evaluated for a given effective type.

Success(TValue)

Creates a new (successful) RuntimeSemanticsEvaluationResult with the specified evaluation result.

public static RuntimeSemanticsEvaluationResult<TValue> Success(TValue result)

Parameters

result TValue

The successfully evaluated runtime semantics evaluation result.

Returns

RuntimeSemanticsEvaluationResult<TValue>

Remarks

✅ Use this method only to signal a successully evaluated expression result.

Operators

implicit operator RuntimeSemanticsEvaluationResult(RuntimeSemanticsEvaluationResult<TValue>)

Widens the result to one whose result type is not stated, discarding nothing.

public static implicit operator RuntimeSemanticsEvaluationResult(RuntimeSemanticsEvaluationResult<TValue> result)

Parameters

result RuntimeSemanticsEvaluationResult<TValue>

The result to widen.

Returns

RuntimeSemanticsEvaluationResult