Display the source code in dmd/expression.d from which this page was generated on github.

If you spot a problem with this page, click here to create a Bugzilla issue.

Quickly fork, edit online, and submit a pull request for this page. Requires a signed-in GitHub account. This works well for small changes. If you'd like to make larger changes you may want to consider using local clone.

Class `dmd.expression.NullExp`

A compile-time known null value


						
				class NullExp
				
  : Expression
				;

Methods

Name	Description
`accept` (v)	Visits this AST node using the given visitor.
`addDtorHook` (sc)	Destructors are attached to VarDeclarations. Hence, if expression returns a temp that needs a destructor, make sure and create a VarDeclaration for that temp.
`addressOf` ()	Take address of expression.
`checkNogc` (sc, f)	Calling function f. Check the @nogc-ness, i.e. if we're in a @nogc function we can only call other @nogc functions. Returns true if error occurs.
`checkOverriddenDtor` (sc, f, check, checkName)	Checks whether `f` is a generated `DtorDeclaration` that hides a user-defined one which passes `check` while `f` doesn't (e.g. when the user defined dtor is pure but the generated dtor is not). In that case the method will identify and print all members causing the attribute missmatch.
`checkPostblit` (sc, t)	Check that the postblit is callable if t is an array of structs. Returns true if error happens.
`checkPurity` (sc, f)	Calling function f. Check the purity, i.e. if we're in a pure function we can only call other pure functions. Returns true if error occurs.
`checkPurity` (sc, v)	Accessing variable v. Check for purity and safety violations. Returns true if error occurs.
`checkReadModifyWrite` (rmwOp, ex)	Check whether the expression allows RMW operations, error with rmw operator diagnostic if not. ex is the RHS expression, or NULL if ++/-- is used (for diagnostics) Returns true if error occurs.
`checkSafety` (sc, f)	Calling function f. Check the safety, i.e. if we're in a @safe function we can only call @safe or @trusted functions. Returns true if error occurs.
`checkType` ()	Check that the expression has a valid type. If not, generates an error "... has no type".
`checkValue` ()	Check that the expression has a valid value. If not, generates an error "... has no value".
`combine` (e1, e2)	Combine e1 and e2 by CommaExp if both are not NULL.
`copy` ()	Does not do a deep copy.
`deinitialize` ()	Deinitializes the global state of the compiler.
`deref` ()	If this is a reference, dereference it.
`extractLast` (e, e0)	If 'e' is a tree of commas, returns the rightmost expression by stripping off it from the tree. The remained part of the tree is returned via e0. Otherwise 'e' is directly returned and e0 is set to NULL.
`factory` (classname)	Create instance of class specified by the fully qualified name classname. The class must either have no constructors or have a default constructor.
`isIdentical` (e)	Identical, not just equal. I.e. NaNs with different bit patterns are not identical
`isLvalue` ()	Return !=0 if expression is an lvalue.
`opCmp` (o)	Compare with another Object obj.
`opEquals` (o)	Test whether `this` is equal to `o`. The default implementation only compares by identity (using the `is` operator). Generally, overrides and overloads for `opEquals` should attempt to compare objects by their contents. A class will most likely want to add an overload that takes your specific type as the argument and does the content comparison. Then you can override this and forward it to your specific typed overload with a cast. Remember to check for `null` on the typed overload.
`resolveLoc` (loc, sc)	Resolve _FILE__, _LINE__, _MODULE__, _FUNCTION__, _PRETTY_FUNCTION__, _FILE_FULL_PATH__ to loc.
`size` ()
`toBool` ()	Statically evaluate this expression to a `bool` if possible
`toHash` ()	Compute hash function for Object.
`toLvalue` (sc, e)	Give error if we're not an lvalue. If we can, convert expression to be an lvalue.
`toString` ()
`toString` ()	Convert Object to a human readable string.

https

//dlang.org/spec/expression.html#null

Authors

Walter Bright

License

Boost License 1.0