objective c - iOS 4 - Using blocks as a member of a class -

i hoping me understand syntax of blocks when used members of class. have code that's working fine:

@class structure; typedef void (^structuredeletecallback)(structure *);  @interface structurelistdelegate : nrfctabledelegate {     structuredeletecallback _structuredeletecallback; }  @property (nonatomic, copy) structuredeletecallback structuredeletecallback;  @end 

this works, understand syntax of typedef statement; , whether or not it's required use typedef.

what i've read says using typedef in situation recommended because makes code lot clearer; i've been unable compile @ when trying without typedef. understanding of typedef syntax basically:

typedef [actual type] [new name type]; 

such as:

typedef double cllocationdegrees; 

but syntax of typedef statement doesn't match this. questions are:

• how can syntax of typedef statement different other typedef statements / syntax i'm using mean compiler?
• is possible have block member of class without using typedef?

i myself have asked question along lines of yours here: block references instance vars in objective-c

see answers here , here.