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tryHooks(HashTable,Thing,Thing) -- try the hook functions stored in an object

Synopsis

Usage:
tryHooks(obj,key,arg)
Function: tryHooks
Inputs:
- obj, a hash table
- key, a thing
- arg, a thing
Consequences:
- the functions hook in list of hooks stored in obj#key or obj.cache#key is called with arg as its argument or sequence of arguments, and when one returns a non-null value, that value is returned and the rest of the hooks are not called

Code

-- ../../../../Macaulay2/m2/methods.m2:441
tryHooks  (HashTable,Thing,Thing   ) := (obj,key,arg ) -> (c := obj.cache; if c#?key then for hook in c#key do ( r := hook arg ; if r =!= null then return r ) )
-- ../../../../Macaulay2/m2/methods.m2:436
tryHooks  (MutableHashTable,Thing,Thing   ) := (obj,key,arg ) -> if obj#?key then for hook in obj#key do ( r := hook arg ; if r =!= null then return r )

See also

addHook -- add a hook function to an object for later processing
removeHook -- remove a hook function from an object
runHooks -- run the hook functions stored in an object