addHook -- add a hook function to an object for later processing

Synopsis

Usage:

addHook(key, hook)

addHook(store, key, hook)
Inputs:
- key, a sequence or a symbol,
- hook, a function,
- store, a mutable hash table,
Optional inputs:
- Strategy => a thing, default value null, specifies the name for the hook
Consequences:
- the function hook is added to the (possibly absent) hash table of hooks, which is either stored in the mutable hash table store or under the youngest Type T listed in the method key key. In the latter case, the hash table is either stored in T.Hooks#key if T is mutable, or in T.cache.Hooks#key otherwise. If no appropriate object is found, or if key is a Symbol, then the hook is stored under the hash table GlobalHookStore

Description

For an explanation and examples of hooks see using hooks.

Code

../../../../../Macaulay2/m2/methods.m2:598:51-607:31: --source code:
addHook(MutableHashTable, Thing, Function) := opts -> (store, key, hook) -> (
    -- this is the hashtable of Hooks for a specific key, which stores HookAlgorithms and HookPriority
    if not store#?key then store#key = new MutableHashTable from {
        HookAlgorithms => new MutableHashTable, -- a mutable hash table "strategy key" => "strategy code"
        HookPriority   => new MutableList},     -- a mutable list of strategy keys, in order
    store = store#key;
    ind := #store.HookPriority; -- index to add the hook in the list; TODO: use Priority to insert in the middle?
    alg := if opts.Strategy =!= null then opts.Strategy else ind;
    store.HookPriority#ind = alg;
    store.HookAlgorithms#alg = hook)

Ways to use addHook :

addHook(MutableHashTable,Thing,Function)
addHook(Sequence,Function)
addHook(Symbol,Function)

For the programmer

The object addHook is a method function with options.

addHook -- add a hook function to an object for later processing

Synopsis

Description

Code

See also

Ways to use addHook :

For the programmer