[Bro-Dev] Closures in Bro

Jan Grashöfer jan.grashoefer at gmail.com
Tue Dec 19 07:54:37 PST 2017

Hi everyone,

playing around with the add-json package, I realized that I will need to 
"extend" functions like the path_func at some point. That is, I need to 
calculate a value using the original version of the function and "add" 
my calculations on top. My approach is to wrap the function, which works 
as long as I don't need "multiple versions" of that function. In the 
latter case closures would help, e.g.:

function do_add(i: int): function(j: int): int
     return function(j: int): int {return i+j; };

However, referencing outer function IDs is not supported (see 

In the light of the flexibility that comes with packages, I think 
supporting closures would be a nice feature. Was there any fundamental 
design decision against supporting closures?


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