hg.stevelosh.com > temperance

test/99.pl @ ba96e98a1d54 

Add precompilation of static queries at compile time

Imagine a function like this:

    (defun legal-moves ()
      (query (legal ?who ?move)))

The argument to `query` there is constant, so we can compile it into WAM
bytecode once, when the Lisp function around it is compiled.  Then running the
query doesn't need to touch the Bones compiler -- it can just load the bytecode
from an array and first up the VM loop.

This saves a lot of time (and consing) compared to compiling the same query over
and over at runtime.
author Steve Losh <steve@stevelosh.com>
date Sun, 17 Jul 2016 16:49:06 +0000
parents 5e0cca5174a8
children 4abb7eda96cb 
% 99 Prolog Problems
% from http://www.ic.unicamp.br/~meidanis/courses/mc336/2009s2/prolog/problemas/
%
% Solutions to at least a few of these, for testing purposes.

% P01
my_last(X, [X]).
my_last(X, [_ | T]) :-
    my_last(X, T).

% P02
my_lastbutone(X, [X, _]).
my_lastbutone(X, [_ | T]) :-
    my_lastbutone(X, T).

% P03
my_nth(X, [X | _], 1).
my_nth(X, [_ | T], N) :-
    M is N - 1,
    my_nth(X, T, M).

% P04
my_len([], 0).
my_len([_ | T], Length) :-
    my_len(T, M),
    Length is M + 1.

my_len_acc([], A, A).
my_len_acc([_ | T], A, Length) :-
    B is A + 1,
    my_len_acc(T, B, Length).

my_len2(L, Length) :-
    my_len_acc(L, 0, Length).

% P05
my_reverse_acc([], Acc, Acc).
my_reverse_acc([X | T], Acc, Reversed) :-
    my_reverse_acc(T, [X | Acc], Reversed).

my_reverse(L, R) :-
    my_reverse_acc(L, [], R).

% P06
my_palindrome(L) :-
    my_reverse(L, L).

% P07
my_flatten([], []).

my_flatten([Atom | Tail], [Atom | FlatTail]) :-
    \+ is_list(Atom),
    my_flatten(Tail, FlatTail).

my_flatten([HeadList | Tail], Flattened) :-
    is_list(HeadList),
    my_flatten(HeadList, FlatHeadList),
    my_flatten(Tail, FlatTail),
    append(FlatHeadList, FlatTail, Flattened).

% P08
my_compress_acc([], A, A).

my_compress_acc([X | T], [X | Acc], Compressed) :-
    my_compress_acc(T, [X | Acc], Compressed).

my_compress_acc([X | T], [Y | Acc], Compressed) :-
    X \= Y,
    my_compress_acc(T, [X, Y | Acc], Compressed).

my_compress([H | T], Compressed) :-
    my_compress_acc(T, [H], ReverseCompressed),
    my_reverse(ReverseCompressed, Compressed).

their_compress([],[]).
their_compress([X],[X]).
their_compress([X,X|Xs],Zs) :- compress([X|Xs],Zs).
their_compress([X,Y|Ys],[X|Zs]) :- X \= Y, compress([Y|Ys],Zs).

% P09
my_pack([], []).
my_pack([X], [[X]]).

my_pack([X | Tail], [[X] | ResultTail]) :-
    my_pack(Tail, ResultTail),
    ResultTail = [[Y | _] | _],
    X \= Y.

my_pack([X | Tail], [[X, X | XS] | ResultTail]) :-
    my_pack(Tail, [[X | XS] | ResultTail]).

their_pack([],[]).
their_pack([X | Tail], [Chunk | PackedTail]) :-
    their_transfer(X, [X | Tail], Remaining, Chunk),
    their_pack(Remaining, PackedTail).

% transfer(X,Xs,Ys,Z) Ys is the list that remains from the list Xs
%    when all leading copies of X are removed and transfered to Z

their_transfer(_, [], [], []).

their_transfer(X, [Y | Ys], [Y | Ys], []) :-
    X \= Y.

their_transfer(X, [X | Xs], Ys, [X | Zs]) :-
    their_transfer(X, Xs, Ys, Zs).