VVMOpResult.h

Go to the documentation of this file.

// Copyright Epic Games, Inc. All Rights Reserved.
 
#pragma once
 
#if WITH_VERSE_VM || defined(__INTELLISENSE__)
 
#include "CoreTypes.h"
#include "VVMValue.h"
 
#define V_RETURN(...)                             \
    return ::Verse::FOpResult                     \
    {                                             \
        ::Verse::FOpResult::Return, (__VA_ARGS__) \
    }
#define V_REQUIRE_CONCRETE(...)                                                          \
    if (VValue MaybePlaceholderVal = (__VA_ARGS__); MaybePlaceholderVal.IsPlaceholder()) \
    {                                                                                    \
        return ::Verse::FOpResult{::Verse::FOpResult::Block, MaybePlaceholderVal};       \
    }
#define V_FAIL_IF(...)                                       \
    if (__VA_ARGS__)                                         \
    {                                                        \
        return ::Verse::FOpResult{::Verse::FOpResult::Fail}; \
    }
#define V_FAIL_UNLESS(...)                                   \
    if (!(__VA_ARGS__))                                      \
    {                                                        \
        return ::Verse::FOpResult{::Verse::FOpResult::Fail}; \
    }
#define V_YIELD()                 \
    return ::Verse::FOpResult     \
    {                             \
        ::Verse::FOpResult::Yield \
    }
 
namespace Verse
{
 
// Represents the result of a single VM operation
struct FOpResult
{
    enum EKind
    {
        Return, // All went well, and Value is the result.
        Block,  // A placeholder was encountered, and this operation should be enqueued on Value.
        Fail,   // The current choice failed. Value is undefined.
        Yield,  // The task suspended, and execution should continue in the resumer. Value is undefined.
        Error,  // A runtime error occurred, and an exception was raised. Value is undefined.
    };
 
    FOpResult()
        : Kind(FOpResult::Error)
    {
    }
 
    FOpResult(EKind Kind, VValue Value = VValue())
        : Kind(Kind)
        , Value(Value)
    {
    }
 
    bool IsReturn() const
    {
        return Kind == Return;
    }
 
    bool IsError() const
    {
        return Kind == Error;
    }
 
    static void AutoRTFMAssignFromOpenToClosed(FOpResult& Closed, const FOpResult& Open)
    {
        Closed = Open;
    }
 
    EKind Kind;
    VValue Value;
};
 
} // namespace Verse
#endif // WITH_VERSE_VM