uk.ac.bbk.dcs.automed.qproc
Interface BuiltInFunction

All Known Implementing Classes:

And, Append, Average, BagIntersect, CallToWrapper, Comprehension, Concat, Count, Difference, Disjunction, Divide, ElementsFromRDB, Equals, First, Flatmap, Foldl, Foldr, GenerateElemUID, generateGID, generateSID, Greater, GreaterEqual, Group, GroupCompute, Id, If, Length, Less, LessEqual, Let, LoadListFromFile, LowerCase, Map, Max, Member, Min, Minus, Monus, Multiply, NestListsFromRDB, NewElemUID, NewNestLists, Not, NotEqual, Or, Plus, Second, SetUnion, Single, Sort, SortDistinct, Split, SubBag, Substring, Substring2, Sum, UpperCase

public interface BuiltInFunction

Interface class for all functions.

Method Summary

int	getArity() Returns the arity of the function.
Cell	perform(Cell[] args, Evaluator e) Returns a Cell object that is the root of a graph that represents the result of applying the built-in function to the arguments args.

Method Detail

getArity

int getArity()

Returns the arity of the function.

perform

Cell perform(Cell[] args,
             Evaluator e)

Returns a Cell object that is the root of a graph that represents the result of applying the built-in function to the arguments args. Uses the Evaluator e to evaluate any sub-queries that need to be evaluated.