go113.go (1451B)
1 // +build go1.13 2 3 package errors 4 5 import ( 6 stderrors "errors" 7 ) 8 9 // Is reports whether any error in err's chain matches target. 10 // 11 // The chain consists of err itself followed by the sequence of errors obtained by 12 // repeatedly calling Unwrap. 13 // 14 // An error is considered to match a target if it is equal to that target or if 15 // it implements a method Is(error) bool such that Is(target) returns true. 16 func Is(err, target error) bool { return stderrors.Is(err, target) } 17 18 // As finds the first error in err's chain that matches target, and if so, sets 19 // target to that error value and returns true. 20 // 21 // The chain consists of err itself followed by the sequence of errors obtained by 22 // repeatedly calling Unwrap. 23 // 24 // An error matches target if the error's concrete value is assignable to the value 25 // pointed to by target, or if the error has a method As(interface{}) bool such that 26 // As(target) returns true. In the latter case, the As method is responsible for 27 // setting target. 28 // 29 // As will panic if target is not a non-nil pointer to either a type that implements 30 // error, or to any interface type. As returns false if err is nil. 31 func As(err error, target interface{}) bool { return stderrors.As(err, target) } 32 33 // Unwrap returns the result of calling the Unwrap method on err, if err's 34 // type contains an Unwrap method returning error. 35 // Otherwise, Unwrap returns nil. 36 func Unwrap(err error) error { 37 return stderrors.Unwrap(err) 38 }