Sometimes it is useful to be able to call a strategy based on its name (as in a string).

An example is the dr-undefine-rules(|Rs,scope,dep) strategy which calls for each R in Rs (a list of strings) the rule undefine-R(|scope,dep). The Rs involved are unknown at the time of definition of dr-undefine-rules.

Plan: add a primitive call(t|s1,…,sn|t1,…,tm) which evaluates the term t, uses the resulting string str and arities to do a lookup in a table, which returns a pointer to the function f implementing the strategy named str_n_m, and calls str_n_m(s1,…,sn,t1,…,tm,cur) with cur the current term.

This requires:

• at start-up time create a table mapping strategy names to function pointers

• declaring which strategies can be called in this way

• implementing the fucntion in C

Advantages

• makes linking libraries into the interpreter trivial

Submitted on 21 July 2005 at 14:39

STR-346, visser:
The `call from name’ feature is a more general solution to this problem.

STR-346, anya:
A version which simply calls a function through a pointer stored in an ATerm would also be useful (and a bit unsafe…).

STR-346, visser:
Is required for M2

STR-346, visser:
This isssue is (temporarily) solved by the DYNAMIC-CALLS hack from issue STR-346. A cleaner solution should be designed eventually. Therefore, leaving this issue open (but moving it to a future release).