4.Simple functional composition
duplicate(X,[X,X]).
%duplicate X : [X,X].
%复制
%Returns XX=6
derive([[dulicate,add],3,XX])
second_degree([A,B,C,X],R) :-
R=A*X*X+B*X+C.

5.Monadic functional composition
1)The Maybe monad
maybe(nothing())
maybe (just (SomeData))
eg:
%输入是0，返回nothing
%输入是数，折半几次，直到结果是nothing.
halve_f 0 : maybe(nothing()) =!.
halve_f Number.A : maybe(just(Number.B))=Number.B=Number.A/2.
2)The List monad
duplicate_m(X,list(X,X)).
eg:
% In Haskell: [1,2,3] >>= duplicate_m >>= duplicate_m
% this returns X3=[list,1,1,1,1,2,2,2,2,3,3,3,3]
:- solve(
derive([[map(duplicate_m),join,map(duplicate_m),join],list(1,2, 3),X3])
).

3)The state monad
%初态
真->大写
假->小写
flipcase([C,true],state([CM,false])):-
CM=c.toUpperCase().
flipcase([C,false],state([C,true])):-
CM=C.toLowerCase().

4)The Fact monad
不改变事实，只产生新的事实
eg:
%data(1,2) -> data(1,3)
%data(3,2) -> data(3,3)

5)Combining monads
6)Stream fusion and unfoldr

1.12 Builtin reference
assert/1 (i)
%仅采用Prova list作为参数，作为事实添加到规则库中，对应提供列表的第一个元素。
asserta/1 (i)
%仅采用Prova list作为参数，针对相同的谓语，将之添加在任何事实之前。
attach/3 (i,i,io)
%1+2->3
bound/1 (i)
byte_stream/2 ([i,i],o)
cache/2 (i)
capture_enum/2 ([i,i],io) ND
clone/2 (i,io)
concat/2 (i, io)
copy/2 (i,i)
copy_stream/2 (i,o)
consult/1 (i)
element/2 (io,i) ND and element/3 (io,io,i) ND
Implementation details
fail/0 ()
findall/3 (i,i,o)
fopen/2 (i,o)
for/2 (i,io) ND
free/1 (i)
listen/2 (i,i)
match/3 (i,io,io)
mklist/2 (i,io) ND
parse_list/2 ([i,i],io)
parse_nv/2 ([i,i],[io,io])
println/1 (i) or println/2 (i,i)
rcvMsg/5 (io,io,io,io,io)
rcvMult/5 (io,io,io,io,io)
read_enum/2 (i,io) ND
retract/1 (i)
retractall/1 (i)
sendMsg/5 (io,i,i,i,i)
sendMsgSync/5 (io,i,i,i,i)
pawn/4 (io,i,i,i)
tokenize_enum/2 ([i,i],io) ND
tokenize_list/2 ([i,i],io)
type/2 (i,io)
unescape/2 (i,o)
unique_id/1 (o)

相关链接
https://prova.ws/confluence/display/REWRITEDEV/Builtins+reference