# Class Expr

A C/C++ expression.

This is the root QL class for all expressions.

## Import path

`import cpp`

## Direct supertypes

## Indirect supertypes

## Known direct subtypes

- Access
- AggregateLiteral
- AlignofOperator
- AnalysedExpr
- AnalysedString
- ArrayExpr
- ArrayLiteral
- AssumeExpr
- AtEncodeExpr
- AtProtocolExpr
- AtSelectorExpr
- BitwiseOperation
- BooleanExpression
- BufferAccess
- BufferSizeExpr
- BufferWrite
- BuiltInOperation
- Call
- CheckForLeapYearOperation
- CmdExpr
- CommaExpr
- CompileTimeConstantInt
- CompileTimeVariableExpr
- ConditionDeclExpr
- ConstantZero
- ConstructorInit
- Conversion
- DataFlowCall
- DataSensitiveCallExpr
- DeleteArrayExpr
- DeleteExpr
- DestructorDestruction
- DictionaryLiteral
- EnvironmentRead
- ErrorExpr
- ExposingIntegralCastExpr
- ExprInVoidContext
- FileWrite
- FoldExpr
- ForStmtSideEffectExpr
- FormattingFunctionCall
- GuardCondition
- GuardCondition
- ImplicitConversion
- IntConstantExpr
- InvalidFloatCastExpr
- LambdaExpression
- Literal
- LogicalOperation
- MacroInvocationExpr
- MessageExpr
- MultipleAssignExpr
- NewOrNewArrayExpr
- NoExceptExpr
- NullPointer
- NullValue
- Operation
- OutputWrite
- ParamAccessForType
- ParameterCheck
- ParenthesizedBracedInitializerList
- PointerArithmeticAccess
- PointsToExpr
- PotentiallyDangerousInput
- Qualifier
- ScanfFormatLiteral
- SensitiveExpr
- SizeofOperator
- SizeofPackOperator
- StmtExpr
- SubscriptExpr
- ThisExpr
- ThrowExpr
- TypeName
- TypeidOperator
- UuidofOperator
- VacuousDestructorCall

## Predicates

getAChild | Gets a child of this expression. |

getActualType | Gets the type of this expression, after any implicit conversions and explicit casts, and after resolving typedefs. |

getChild | Gets the nth child of this expression. |

getControlFlowScope | Gets the function containing this control-flow node. |

getConversion | Gets the conversion associated with this expression, if any. |

getConversionString | Gets a string describing the conversion associated with this expression, or "" if there is none. |

getEnclosingBlock | Gets the nearest enclosing set of curly braces around this expression in the source, if any. |

getEnclosingFunction | Gets the enclosing function of this expression, if any. |

getEnclosingStmt | Gets the smallest statement containing this control-flow node. |

getEnclosingVariable | Gets the enclosing variable of this expression, if any. |

getExplicitlyConverted | Gets this expression with all of its explicit casts, but none of its implicit casts. More precisely this takes conversions up to the last explicit cast (there may be implicit conversions along the way), but does not include conversions after the last explicit cast. |

getFullyConverted | Gets the fully converted form of this expression, including all type casts and other conversions. |

getImplicitlyConverted | Gets this expression with all of its initial implicit casts, but none of its explicit casts. More precisely, this takes all implicit conversions up to (but not including) the first explicit cast (if any). |

getKind | Gets an integer indicating the type of expression that this represents. |

getLocation | Gets the location of this expression. |

getNumChild | Gets the number of direct children of this expression. |

getParent | Gets the parent of this expression, if any. |

getParentWithConversions | Gets the parent of this expression, if any, in an alternative syntax tree that has |

getPrecedence | Gets the precedence of the main operator of this expression; higher precedence binds tighter. |

getType | Gets the type of this expression. |

getUnderlyingType | Gets the type of this expression after typedefs have been resolved. |

getUnspecifiedType | Gets the type of this expression after specifiers have been deeply stripped and typedefs have been resolved. |

getValue | Gets the value of this expression, if it is a constant. |

getValueCategoryString | Gets a string representation of the value category of the expression. This is intended only for debugging. The possible values are: |

getValueText | Gets the source text for the value of this expression, if it is a constant. |

hasChild | Holds if e is the nth child of this expression. |

hasConversion | Holds if this expression has a conversion. |

hasExplicitConversion | Holds if this expression has an explicit conversion. |

hasImplicitConversion | Holds if this expression has an implicit conversion. |

hasLValueToRValueConversion | Holds if this expression has undergone an |

isCompilerGenerated | Holds if this is an auxiliary expression generated by the compiler. |

isConstant | Holds if this expression has a value that can be determined at compile time. |

isGLValueCategory | Holds if this expression is a |

isLValue | Holds if this expression is an |

isLValueCategory | Holds if this expression is an |

isPRValueCategory | Holds if this expression is a |

isParenthesised | Holds if this expression is parenthesised. |

isPure | Holds if this expression is side-effect free (conservative approximation). This predicate cannot be overridden; override mayBeImpure() instead. |

isRValueCategory | Holds if this expression is an |

isUnevaluated | Holds if this expression will not be evaluated because of its context, such as an expression inside a sizeof. |

isXValueCategory | Holds if this expression is an |

mayBeGloballyImpure | Holds if it is possible that the expression may be impure. If we are not sure, then it holds. Unlike |

mayBeImpure | Holds if it is possible that the expression may be impure. If we are not sure, then it holds. |

toString | Gets a textual representation of this expression. |

## Inherited predicates

findRootCause | Gets the source of this element: either itself or a macro that expanded to this element. | from Element |

fromLibrary | Holds if this element may be from a library. | from Element |

fromSource | Holds if this element may be from source. | from Element |

getAFalseSuccessor | Gets a node such that the control-flow edge | from ControlFlowNode |

getAPredecessor | from ControlFlowNode | |

getASuccessor | from ControlFlowNode | |

getATrueSuccessor | Gets a node such that the control-flow edge | from ControlFlowNode |

getBasicBlock | from ControlFlowNode | |

getCanonicalQLClass | Canonical QL class corresponding to this element. | from ElementBase |

getEnclosingElement | Gets the closest | from Element |

getFile | Gets the primary file where this element occurs. | from Element |

getParentScope | Gets the parent scope of this | from Element |

isAffectedByMacro | Holds if this element is affected in any way by a macro. All elements that are totally or partially generated by a macro are included, so this is a super-set of | from Element |

isCondition | Holds if this node is the top-level expression of a conditional statement, meaning that | from ControlFlowNode |

isFromTemplateInstantiation | Holds if this | from Element |

isFromUninstantiatedTemplate | Holds if this | from Element |

isInMacroExpansion | Holds if this element comes from a macro expansion. Only elements that are entirely generated by a macro are included - for elements that partially come from a macro, see | from Element |