UnknownType.h

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// Copyright Epic Games, Inc. All Rights Reserved.
// uLang Compiler Public API
 
#pragma once
 
#include "uLang/Common/Containers/SharedPointer.h"
#include "uLang/Common/Containers/SharedPointerArray.h"
#include "uLang/Common/Containers/UniquePointer.h"
#include "uLang/Semantics/SemanticClass.h"
 
#define UE_API VERSECOMPILER_API
 
namespace uLang
{
 
class CUnknownType : public CNormalType
{
public:
    static constexpr ETypeKind StaticTypeKind = ETypeKind::Unknown;
 
    mutable TArray<const CTypeBase *> _SuggestedTypes;
 
    CUnknownType(const CSymbol& Name, CScope& EnclosingScope) : CNormalType(ETypeKind::Unknown, EnclosingScope.GetProgram()), _Name(Name) {}
 
    virtual CUTF8String AsCodeRecursive(ETypeSyntaxPrecedence /*OuterPrecedence*/, TArray<const CFlowType*>& /*VisitedFlowTypes*/, bool bLinkable, ETypeStringFlag Flag) const override { return "$unknown"; }
 
    virtual bool IsPersistable() const override { return true; }
 
    virtual bool IsExplicitlyCastable() const override { return true; }
 
    virtual bool IsExplicitlyConcrete() const override { return true; }
 
    virtual bool CanBeCustomAccessorDataType() const override { return false; }
 
    const CSymbol& _Name;
};
 
class CExprError : public CExpressionBase
{
public:
    UE_API CExprError(TUPtr<CUnknownType>&& ExprType = nullptr, bool bCanFail = false);
 
    virtual EAstNodeType GetNodeType() const override    { return EAstNodeType::Error_; }
    virtual CUTF8String GetErrorDesc() const override    { return "error"; }
    UE_API virtual const CTypeBase* GetResultType(const CSemanticProgram& Program) const override;
    virtual bool CanFail(const CAstPackage* Package) const override { return _bCanFail; }
 
    // We hold onto child expressions in service of semantic analysis -- we may want info
    // for nested expressions, which may be well-formed, even if this parent was not fully formed.
    void AppendChild(TSPtr<CAstNode>&& Child) { _UnknownChildren.Add(Move(Child)); }
 
    virtual void VisitChildren(SAstVisitor& Visitor) const override { Visitor.VisitArray("UnknownChildren", _UnknownChildren); }
 
    virtual bool operator==(const CExpressionBase& Other) const override { return false; } // Never equal
 
private:
    TUPtr<CUnknownType> _ExprType;
    TSPtrArray<CAstNode> _UnknownChildren;
    bool _bCanFail;
};
 
class CExprPlaceholder : public CExpressionBase
{
public:
    UE_API CExprPlaceholder(TUPtr<CUnknownType>&& ExprType = nullptr);
 
    virtual EAstNodeType GetNodeType() const override    { return EAstNodeType::Placeholder_; }
    virtual CUTF8String GetErrorDesc() const override    { return "placeholder"; }
    UE_API virtual const CTypeBase* GetResultType(const CSemanticProgram& Program) const override;
 
    virtual bool operator==(const CExpressionBase& Other) const override { return false; } // Never equal
 
private:
    TUPtr<CUnknownType> _ExprType;
};
 
}  // namespace uLang
 
#undef UE_API