Memoizing with read only side effects
View Patent ↗A function may be memoized when a side effect is a read only side effect. Provided that the read only side effect does not mutate a memory object, the side effect may be considered as an input to a function for purity and memoization analysis. When a read only side effect may be encountered during memoization analysis, the read only side effect may be treated as an input to a function for memoization analysis. In some cases, such side effects may enable an impure function to behave as a pure function for the purposes of memoization.
1. A method performed by at least one processor, said method comprising:
receiving operational results for an application comprising a first function, said operational results comprising inputs to said first function, results returned from said first function, and a state associated with said inputs to said first function;
said operational results being collected by a tracer;
determining that a first side effect comprises reading a first memory object, said state comprising values for said first memory object;
determining that said first side effect does not comprise mutating said first memory object;
determining that said first function returns a first value given a first condition, said first condition comprising a first set of input parameter values and a first value for said first memory object;
causing said first function to be memoized under said first condition without collecting said operational results by said tracer.
2. The method of claim 1 further comprising:
analyzing said operational results and determining that said first function under said first condition returns a consistent result.
3. The method of claim 2 , said consistent result being determined within a statistical certainty.
4. The method of claim 2 , said plurality of operational results being captured during executing an application comprising said first function.
5. The method of claim 4 , said application being executed under simulated loads.
6. The method of claim 4 , said application being executed under actual loads.
7. The method of claim 4 further comprising:
determining that said first function returns a second value under a second condition, said second condition comprising said first set of input parameter values and a second value for said first memory object; and
causing said first function to be memoized under said second condition.
8. The method of claim 7 further comprising:
determining that said first function returns inconsistent values under a third condition, said third condition comprising said first set of input parameter values and a third value for said first memory object; and
causing said first function not to be memoized under said third condition.
9. The method of claim 8 further comprising:
receiving said operational results from a client device.
10. The method of claim 9 further comprising:
storing a record in a configuration database for memoizing said first function.
11. The method of claim 10 , said record indicating that said first function is memoizable under said first condition.
12. The method of claim 11 , said record indicating that said first function is not memoizable under said third condition.
13. A system comprising:
a processor;
a purity analyzer operating on said processor, said purity analyzer that:
receives operational results for an application comprising a first function, said operational results comprising inputs to said first function, results returned from said first function, and a state associated with said inputs to said first function;
said operational results being collected by a tracer;
determines that a first side effect comprises reading a first memory object, said state comprising values for said first memory object;
determines that said first side effect does not comprise mutating said first memory object;
determines that said first function returns a first value given a first condition, said first condition comprising a first set of input parameter values and a first value for said first memory object;
stores said first function and said first condition in a configuration database, said configuration database being used to execute said application without said tracer to memoize said first function.
14. The system of claim 13 further comprising:
a distribution server that transmits said configuration database to a client device.
15. The system of claim 14 further comprising:
an instrumented execution environment that executes an application comprising said first function and generates said operational results.
16. The system of claim 15 , said instrumented execution environment that further executes said application under simulated loads.
17. The system of claim 16 , said purity analyzer that further:
determines that said first function returns inconsistent values under a second condition, said second condition comprising said first set of input parameter values and a second value for said first memory object; and
stores said first function and said second condition in said configuration database as being not memoizable.
18. The system of claim 17 further comprising:
a static code analyzer that examines said application to identify said first function as impure.
19. The system of claim 18 , said static code analyzer that analyzes said application in source code form.