# Section 8.5.3.1.5:
$FILTERS

abstract class $FILTERS {ETP, CTP < $ELT{ETP}} is -- This abstraction models a container for which quantifiers are -- provided and for which sequences of elements satisfying some particular -- predicate may be retrieved. count_if( predicate : ROUT{ETP} : BOOL ) : CARD ; -- This routine returns the number of elements of self which satisfy -- the given predicate. exists( predicate : ROUT{ETP} : BOOL ) : BOOL ; -- This predicate returns true if and only if an element of self -- which satisfies the predicate test exists. exists( predicate : ROUT{ETP} : BOOL, out res : ETP ) : BOOL ; -- This routine returns true if and only if self has at least one -- element that satisfies the predicate. The out argument 'res' is set to -- have the element value concerned if true is returned. not_exists( predicate : ROUT{ETP} : BOOL ) : BOOL ; -- This predicate returns true if and only if no element of self -- satisfies the given predicate. every( predicate : ROUT{ETP} : BOOL ) : BOOL ; -- This predicate returns true if and only if every element of self -- satisfies the given predicate. not_every( predicate : ROUT{ETP} :BOOL ) : BOOL ; -- This predicate returns true if at least one element of self fails -- the given predicate. unique! : ETP ; -- This iter yields in turn all of the elements of the given container -- which are unique. filter!( once predicate : ROUT{ETP} : BOOL ) : ETP ; -- This iter yields in turn all of the elements which satisfy the given -- predicate. not_filter!( once predicate : ROUT{ETP} : BOOL ) : ETP ; -- This iter yields in turn all of the elements which do NOT satisfy -- the given predicate.

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Comments or enquiries should be made to Keith Hopper. Page last modified: Monday, 26 February 2001. |