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Self:: $instance null | | ! (Self:: $instance instanceof TPL

Source: Internet
Author: User
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Self:: $instance = = = NULL | | ! (Self:: $instance instanceof TPL)
What's the meaning of this sentence?


Reply to discussion (solution)

Instance instances

Self:: $instance represents a static property of a class
Here, it means that an instantiated object is stored

Self:: $instance = = = NULL is not instantiated

Self:: $instance instanceof TPL represents self:: $instance the Saved object belongs to the class TPL
! (Self:: $instance instanceof TPL) is an object that is not generated from a TPL or its derived classes

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