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Lazy evaluation library
Author(s): Amadeo Casas, Jose F. Morales.
This module provides several predicates that make easier to develop predicates that will be executed lazily.
Usage and interface
- Library usage:
:- use_module(library(lazy/lazy_lib)). - Exports:
- Predicates:
nums_from/2, nums_from_inc/3, repeat/2, cycle/2, take/3, takeWhile/3, drop/3, dropWhile/3, splitAt/3, span/3, tail/2, lazy_map/3, lazy_foldr/4, lazy_foldl/4, zipWith/4.
- Predicates:
Documentation on exports
PREDICATEnums_from/2
Usage:nums_from(X,List)
List is unified with an infinite list of successive numbers starting in X
- The following properties should hold at call time:
(term_typing:nonvar/1)X is currently a term which is not a free variable.
(term_typing:var/1)List is a free variable.
(basic_props:int/1)X is an integer.
(term_typing:var/1)List is a free variable. - The following properties should hold upon exit:
(basic_props:int/1)X is an integer.
(basic_props:list/2)List is a list of ints.
PREDICATEnums_from_inc/3
Usage:nums_from_inc(X,Y,List)
List is unified with an infinite list of successive numbers starting in X with an increment of Y
- The following properties should hold at call time:
(term_typing:nonvar/1)X is currently a term which is not a free variable.
(term_typing:nonvar/1)Y is currently a term which is not a free variable.
(term_typing:var/1)List is a free variable.
(basic_props:int/1)X is an integer.
(basic_props:int/1)Y is an integer.
(term_typing:var/1)List is a free variable. - The following properties should hold upon exit:
(basic_props:int/1)X is an integer.
(basic_props:int/1)Y is an integer.
(basic_props:list/2)List is a list of ints.
PREDICATErepeat/2
Usage:repeat(X,List)
List is unified with an infinite list of the term Y
- The following properties should hold at call time:
(term_typing:nonvar/1)X is currently a term which is not a free variable.
(term_typing:var/1)List is a free variable.
(basic_props:term/1)X is any term.
(term_typing:var/1)List is a free variable. - The following properties should hold upon exit:
(basic_props:term/1)X is any term.
(basic_props:list/2)List is a list of terms.
PREDICATEcycle/2
Usage:cycle(X,List)
List is unified with an infinite list of the term Y repeated infinite times
- The following properties should hold at call time:
(term_typing:nonvar/1)X is currently a term which is not a free variable.
(term_typing:var/1)List is a free variable.
(basic_props:term/1)X is any term.
(term_typing:var/1)List is a free variable. - The following properties should hold upon exit:
(basic_props:term/1)X is any term.
(basic_props:list/2)List is a list of terms.
PREDICATEtake/3
Usage:take(X,ListA,ListR)
ListR is unified with the first X elements of the infinite list ListA
- The following properties should hold at call time:
(term_typing:nonvar/1)X is currently a term which is not a free variable.
(term_typing:nonvar/1)ListA is currently a term which is not a free variable.
(term_typing:var/1)ListR is a free variable.
(lazy_lib:counter/1)X is a counter.
(basic_props:list/2)ListA is a list of terms.
(basic_props:term/1)ListR is any term. - The following properties should hold upon exit:
(lazy_lib:counter/1)X is a counter.
(basic_props:list/2)ListA is a list of terms.
(basic_props:list/2)ListR is a list of terms.
PREDICATEtakeWhile/3
Usage:takeWhile(P,ListA,ListR)
ListR is unified with the first elements of the infinite list ListA while the condition P is true
- The following properties should hold at call time:
(term_typing:nonvar/1)P is currently a term which is not a free variable.
(term_typing:nonvar/1)ListA is currently a term which is not a free variable.
(term_typing:var/1)ListR is a free variable.
(basic_props:cgoal/1)P is a term which represents a goal, i.e., an atom or a structure.
(basic_props:list/2)ListA is a list of terms.
(basic_props:term/1)ListR is any term. - The following properties should hold upon exit:
(basic_props:cgoal/1)P is a term which represents a goal, i.e., an atom or a structure.
(basic_props:list/2)ListA is a list of terms.
(basic_props:list/2)ListR is a list of terms.
PREDICATEdrop/3
Usage:drop(X,ListA,ListR)
ListR is unified with the infinite list ListA dropping the first X elements
- The following properties should hold at call time:
(term_typing:nonvar/1)X is currently a term which is not a free variable.
(term_typing:nonvar/1)ListA is currently a term which is not a free variable.
(term_typing:var/1)ListR is a free variable.
(lazy_lib:counter/1)X is a counter.
(basic_props:list/2)ListA is a list of terms.
(basic_props:term/1)ListR is any term. - The following properties should hold upon exit:
(lazy_lib:counter/1)X is a counter.
(basic_props:list/2)ListA is a list of terms.
(basic_props:list/2)ListR is a list of terms.
PREDICATEdropWhile/3
Usage:dropWhile(P,ListA,ListR)
ListR is unified with the infinite list ListA dropping the first elements while the condition P is true
- The following properties should hold at call time:
(term_typing:nonvar/1)P is currently a term which is not a free variable.
(term_typing:nonvar/1)ListA is currently a term which is not a free variable.
(term_typing:var/1)ListR is a free variable.
(basic_props:cgoal/1)P is a term which represents a goal, i.e., an atom or a structure.
(basic_props:list/2)ListA is a list of terms.
(basic_props:term/1)ListR is any term. - The following properties should hold upon exit:
(basic_props:cgoal/1)P is a term which represents a goal, i.e., an atom or a structure.
(basic_props:list/2)ListA is a list of terms.
(basic_props:list/2)ListR is a list of terms.
PREDICATEsplitAt/3
Usage:splitAt(X,ListA,Res)
Res is unified with a tuple of lists where the first list is composed by the first X elements of the list ListA and the second list is composed by the rest of the elements of ListA
- The following properties should hold at call time:
(term_typing:nonvar/1)X is currently a term which is not a free variable.
(term_typing:nonvar/1)ListA is currently a term which is not a free variable.
(term_typing:var/1)Res is a free variable.
(lazy_lib:counter/1)X is a counter.
(basic_props:list/2)ListA is a list of terms.
(basic_props:term/1)Res is any term. - The following properties should hold upon exit:
(lazy_lib:counter/1)X is a counter.
(basic_props:list/2)ListA is a list of terms.
(lazy_lib:tuple_of_lists/1)This type represents a tuple of lists.
PREDICATEspan/3
Usage:span(P,ListA,Res)
Res is unified with a tuple of lists where the first list is composed by the elements of ListA which verify the condition P and the second list is composed by the rest of the elements of the initial list
- The following properties should hold at call time:
(term_typing:nonvar/1)P is currently a term which is not a free variable.
(term_typing:nonvar/1)ListA is currently a term which is not a free variable.
(term_typing:var/1)Res is a free variable.
(basic_props:cgoal/1)P is a term which represents a goal, i.e., an atom or a structure.
(basic_props:list/2)ListA is a list of terms.
(basic_props:term/1)Res is any term. - The following properties should hold upon exit:
(basic_props:cgoal/1)P is a term which represents a goal, i.e., an atom or a structure.
(basic_props:list/2)ListA is a list of terms.
(lazy_lib:tuple_of_lists/1)This type represents a tuple of lists.
PREDICATEtail/2
Usage:tail(ListA,ListR)
ListR is unified with the tail of the infinite list ListA
- The following properties should hold at call time:
(term_typing:nonvar/1)ListA is currently a term which is not a free variable.
(term_typing:var/1)ListR is a free variable.
(basic_props:list/2)ListA is a list of terms.
(basic_props:term/1)ListR is any term. - The following properties should hold upon exit:
(basic_props:list/2)ListA is a list of terms.
(basic_props:list/2)ListR is a list of terms.
PREDICATElazy_map/3
Usage:lazy_map(ListA,P,ListR)
Version of the map/3 predicate to be executed lazily
- The following properties should hold at call time:
(term_typing:nonvar/1)ListA is currently a term which is not a free variable.
(term_typing:nonvar/1)P is currently a term which is not a free variable.
(term_typing:var/1)ListR is a free variable.
(basic_props:list/2)ListA is a list of terms.
(basic_props:cgoal/1)P is a term which represents a goal, i.e., an atom or a structure.
(basic_props:term/1)ListR is any term. - The following properties should hold upon exit:
(basic_props:list/2)ListA is a list of terms.
(basic_props:cgoal/1)P is a term which represents a goal, i.e., an atom or a structure.
(basic_props:list/2)ListR is a list of terms.
PREDICATElazy_foldr/4
Usage:lazy_foldr(P,Xs,V0,V)
Lazy version of foldr/4
- Call and exit should be compatible with:
(basic_props:cgoal/1)P is a term which represents a goal, i.e., an atom or a structure.
(basic_props:list/2)Xs is a list of terms.
(basic_props:term/1)V0 is any term.
(basic_props:term/1)V is any term. - The following properties should hold at call time:
(term_typing:nonvar/1)P is currently a term which is not a free variable.
(term_typing:nonvar/1)Xs is currently a term which is not a free variable.
(term_typing:nonvar/1)V0 is currently a term which is not a free variable.
(term_typing:var/1)V is a free variable.
PREDICATElazy_foldl/4
Usage:lazy_foldl(P,Xs,V0,V)
Lazy version of foldl/4
- Call and exit should be compatible with:
(basic_props:cgoal/1)P is a term which represents a goal, i.e., an atom or a structure.
(basic_props:list/2)Xs is a list of terms.
(basic_props:term/1)V0 is any term.
(basic_props:term/1)V is any term. - The following properties should hold at call time:
(term_typing:nonvar/1)P is currently a term which is not a free variable.
(term_typing:nonvar/1)Xs is currently a term which is not a free variable.
(term_typing:nonvar/1)V0 is currently a term which is not a free variable.
(term_typing:var/1)V is a free variable.
PREDICATEzipWith/4
Usage:zipWith(P,ListA,ListB,ListR)
ListR is a list whose elements are calculated from the function P and the elements of input lists ListA and ListB occuring at the same position in both lists
- The following properties should hold at call time:
(term_typing:nonvar/1)P is currently a term which is not a free variable.
(term_typing:nonvar/1)ListA is currently a term which is not a free variable.
(term_typing:nonvar/1)ListB is currently a term which is not a free variable.
(term_typing:var/1)ListR is a free variable.
(basic_props:cgoal/1)P is a term which represents a goal, i.e., an atom or a structure.
(basic_props:list/2)ListA is a list of terms.
(basic_props:list/2)ListB is a list of terms.
(basic_props:term/1)ListR is any term. - The following properties should hold upon exit:
(basic_props:cgoal/1)P is a term which represents a goal, i.e., an atom or a structure.
(basic_props:list/2)ListA is a list of terms.
(basic_props:list/2)ListB is a list of terms.
(basic_props:list/2)ListR is a list of terms.
Documentation on imports
This module has the following direct dependencies:- System library modules:
freeze, arithpreds. - Packages:
prelude, initial, condcomp, regtypes, fsyntax, assertions, assertions/assertions_basic, basicmodes, hiord, lazy.