Well known from html, marquee is clearly the pinnacle of the Semantic Web. Or rather its nadir side by side with the blink tag. In any case, how can we represent marquee in Prolog? In other words, how to define a relation marquee/2 such that the following holds:

众所周知，marquee源自html，显然是语义网的巅峰。或者更确切地说，它的最低点与眨眼标签并排。无论如何，我们如何在PROLOG中表示Marquee？换句话说，如何定义关系字幕/2以使下列条件成立：

?- marquee("Prolog is marquee ready! ",M).
   M = "Prolog is marquee ready! "
;  M = "rolog is marquee ready! P"
;  M = "olog is marquee ready! Pr"
;  M = "log is marquee ready! Pro"
;  M = "og is marquee ready! Prol"
;  M = "g is marquee ready! Prolo"
;  M = " is marquee ready! Prolog"
;  M = "is marquee ready! Prolog "
;  M = "s marquee ready! Prolog i"
;  M = " marquee ready! Prolog is"
;  M = "marquee ready! Prolog is "
;  ... .
?- M=[m|_],marquee("Prolog is marquee ready! ",M).
   M = "marquee ready! Prolog is "
;  M = "marquee ready! Prolog is "
;  M = "marquee ready! Prolog is " % infinitely many redundant answers
;  ... .

So how can I define marquee/2 in ISO Prolog just using the Prolog prologue? The double quotes above assume set_prolog_flag(double_quotes, chars), and the answer write option max_depth(0) needs to be set to get the entire string.

那么，我如何仅使用序言来定义ISO Prolog中的marquee/2呢？上面的双引号假定SET_PROLOG_FLAG(DOUBLE_QUOTES，CHARS)，并且需要设置答案写入选项max_Deep(0)以获得整个字符串。

What I have tried is member/2 but it only describes the characters and then I tried nth0/3 and nth1/3 but they only described two characters in sequence as in:

我尝试的是Members/2，但它只描述了字符，然后我尝试了nth0/3和nth1/3，但它们只按如下顺序描述了两个字符：

?- T = "Prolog is marquee ready! ", nth1(I,T,A),nth0(I,T,B).
   T = "Prolog is marquee ready! ", I = 1, A = 'P', B = r
;  T = "Prolog is marquee ready! ", I = 2, A = r, B = o
;  ... .

Edit: one clarification about the repetitions. They should fit together seamlessly, as in

编辑：对重复内容进行一次澄清。它们应该无缝地结合在一起，就像

?- marquee("! ",M).
   M = "! "
;  M = " !"
;  M = "! "
;  M = " !"
;  M = "! "
;  M = " !"
;  M = "! "
;  M = " !"
;  M = "! "
;  M = " !"
;  ... .

First, hat tip to this answer and the author, @brebs.

首先，向这个答案和作者致敬，@brebs。

I looked at marquee_/3 ... and append/3 looked back at me—with shuffled arguments.

我看着字幕_/3...Append/3回头看着我--带着杂乱无章的论点。

So here's the minimally updated version of marquee/2:

下面是Marquee/2的最低更新版本：

marquee(L,M) :-
   append(L,R,LD),
   append(R,M,LD).   % was: marquee_(LD,R,M)

Sample queries:

示例查询：

?- marquee("prolog",Xs).
   Xs = "prolog"
;  Xs = "rologp"
;  Xs = "ologpr"
;  Xs = "logpro"
;  Xs = "ogprol"
;  Xs = "gprolo"
;  Xs = "prolog"
;  Xs = "rologp"
;  ... .

?- marquee("",Xs).
   Xs = []
;  Xs = []
;  ... .

this is an alternative solution (updated after a suggestion in the comments), hope this solves the task

这是一个替代的解决方案(在评论中的建议之后更新)，希望这能解决任务

marquee(String,String).
marquee([H|T],R):-
    append(T,[H],NewEl),
    marquee(NewEl,R).


?- marquee("Prolog is marquee ready! ", M).
M = ['P', r, o, l, o, g, ' ', i, s, ' ', m, a, r, q, u, e, e, ' ', r, e, a, d, y, !, ' '];
M = [r, o, l, o, g, ' ', i, s, ' ', m, a, r, q, u, e, e, ' ', r, e, a, d, y, !, ' ', 'P'];
...

?- M=[m|_],marquee("Prolog is marquee ready! ",M).
M = [m, a, r, q, u, e, e, ' ', r, e, a, d, y, !, ' ', 'P', r, o, l, o, g, ' ', i, s, ' '];
M = [m, a, r, q, u, e, e, ' ', r, e, a, d, y, !, ' ', 'P', r, o, l, o, g, ' ', i, s, ' '];
...

Im not sure this satisfy all your requisites, hope so

我不能肯定这能满足你所有的要求，希望如此

marquee(Ls, M):- 
    length(Ls, Len), 
    Max is Len-1,
    between(0, Max, Roll),
    roll(Ls, M, Roll).

lis_pos_elem(Lis, Pos, Elem) :- nth1(Pos, Lis, Elem).

new_index(Shift, Max, I1, I2):-
    I is I1 - Shift,
    ( 
        I < 1,
        I2 is Max + I
    ;
        I2 = I
    ), !.

roll(L,L,0).
roll(L1,L2,R):-
    R > 0,
    length(L1, Len),
    numlist(1, Len, Index),
    maplist(new_index(R, Len), Index, ShiftedIndexes), 
    maplist(lis_pos_elem(L1), ShiftedIndexes, L2).

?-
marquee("Prolog is marquee ready! ", M); true.
M = ['P', r, o, l, o, g, ' ', i, s, ' ', m, a, r, q, u, e, e, ' ', r, e, a, d, y, !, ' '] ;
M = [' ', 'P', r, o, l, o, g, ' ', i, s, ' ', m, a, r, q, u, e, e, ' ', r, e, a, d, y, !] ;
M = [!, ' ', 'P', r, o, l, o, g, ' ', i, s, ' ', m, a, r, q, u, e, e, ' ', r, e, a, d, y] ;
M = [y, !, ' ', 'P', r, o, l, o, g, ' ', i, s, ' ', m, a, r, q, u, e, e, ' ', r, e, a, d] ;
M = [d, y, !, ' ', 'P', r, o, l, o, g, ' ', i, s, ' ', m, a, r, q, u, e, e, ' ', r, e, a] ;
M = [a, d, y, !, ' ', 'P', r, o, l, o, g, ' ', i, s, ' ', m, a, r, q, u, e, e, ' ', r, e] ;
M = [e, a, d, y, !, ' ', 'P', r, o, l, o, g, ' ', i, s, ' ', m, a, r, q, u, e, e, ' ', r] ;
M = [r, e, a, d, y, !, ' ', 'P', r, o, l, o, g, ' ', i, s, ' ', m, a, r, q, u, e, e, ' '] ;
M = [' ', r, e, a, d, y, !, ' ', 'P', r, o, l, o, g, ' ', i, s, ' ', m, a, r, q, u, e, e] ;
M = [e, ' ', r, e, a, d, y, !, ' ', 'P', r, o, l, o, g, ' ', i, s, ' ', m, a, r, q, u, e] ;
M = [e, e, ' ', r, e, a, d, y, !, ' ', 'P', r, o, l, o, g, ' ', i, s, ' ', m, a, r, q, u] ;
M = [u, e, e, ' ', r, e, a, d, y, !, ' ', 'P', r, o, l, o, g, ' ', i, s, ' ', m, a, r, q] ;
M = [q, u, e, e, ' ', r, e, a, d, y, !, ' ', 'P', r, o, l, o, g, ' ', i, s, ' ', m, a, r] ;
M = [r, q, u, e, e, ' ', r, e, a, d, y, !, ' ', 'P', r, o, l, o, g, ' ', i, s, ' ', m, a] ;
M = [a, r, q, u, e, e, ' ', r, e, a, d, y, !, ' ', 'P', r, o, l, o, g, ' ', i, s, ' ', m] ;
M = [m, a, r, q, u, e, e, ' ', r, e, a, d, y, !, ' ', 'P', r, o, l, o, g, ' ', i, s, ' '] ;
M = [' ', m, a, r, q, u, e, e, ' ', r, e, a, d, y, !, ' ', 'P', r, o, l, o, g, ' ', i, s] ;
M = [s, ' ', m, a, r, q, u, e, e, ' ', r, e, a, d, y, !, ' ', 'P', r, o, l, o, g, ' ', i] ;
M = [i, s, ' ', m, a, r, q, u, e, e, ' ', r, e, a, d, y, !, ' ', 'P', r, o, l, o, g, ' '] ;
M = [' ', i, s, ' ', m, a, r, q, u, e, e, ' ', r, e, a, d, y, !, ' ', 'P', r, o, l, o, g] ;
M = [g, ' ', i, s, ' ', m, a, r, q, u, e, e, ' ', r, e, a, d, y, !, ' ', 'P', r, o, l, o] ;
M = [o, g, ' ', i, s, ' ', m, a, r, q, u, e, e, ' ', r, e, a, d, y, !, ' ', 'P', r, o, l] ;
M = [l, o, g, ' ', i, s, ' ', m, a, r, q, u, e, e, ' ', r, e, a, d, y, !, ' ', 'P', r, o] ;
M = [o, l, o, g, ' ', i, s, ' ', m, a, r, q, u, e, e, ' ', r, e, a, d, y, !, ' ', 'P', r] ;
M = [r, o, l, o, g, ' ', i, s, ' ', m, a, r, q, u, e, e, ' ', r, e, a, d, y, !, ' ', 'P'] ;
true.

This feels fairly intuitive, but not super-short:

这感觉相当直观，但不是太短：

marquee(L, M) :-
    % Convert to List-Remainder difference list
    append(L, R, LD),
    marquee_(LD, R, M).

marquee_(M, [], M).
% Move from head to tail
marquee_([H|T], [H|R], M) :-
    marquee_(T, R, M).

Result in swi-prolog:

结果以swi-prolog格式显示：

?- marquee([a,b,c,d], L).
L = [a, b, c, d] ;
L = [b, c, d, a] ;
L = [c, d, a, b] ;
L = [d, a, b, c] ;
L = [a, b, c, d] ;
L = [b, c, d, a] ;
...

I suspect there's a trick to convert that into a short DCG that I'm missing...

我怀疑有一个诀窍可以把它转换成我错过的短DCG...

This is my updated answer:

这是我的最新答案：

marquee_right(S0, M):- 
    length(S0, Len),
    length(_, Roll), 
    Shift is Len - (Roll mod Len),
    length(P1, Shift),
    append(P1, P2, S0),
    append(P2, P1, M).

marquee_left(S0, M):- 
    length(S0, Len),
    length(_, Roll), 
    Shift is Roll mod Len,
    length(P1, Shift),
    append(P1, P2, S0),
    append(P2, P1, M).

@damianodamiano answer seems really good and declarative, maybe my answer follow more a procedural style.
Comments and notes are appreciated.

@DamianoDamiano的回答看起来真的很好，很有说服力，也许我的回答更像是程序化的风格。欢迎提出意见和备注。

Rolling rolling rolling ...

滚动..。

marquee([],[]) :- repeat, true.
marquee([H|T],X) :- m(T,R,[H|R],X).
m([H|T],[H|R],Y,X) :- m(T,R,Y,X).
m([],[],Y,Y).
m([],[H|Z],[H|R],X) :- m([],Z,R,X).

Testing:

测试：

8 ?- marquee([],X).
X = [] ;
X = [] ;
X = [] ;
X = [] ;
X = [] ;
X = [] 
......

9 ?- marquee([1,2,3,4],X).
X = [1, 2, 3, 4] ;
X = [2, 3, 4, 1] ;
X = [3, 4, 1, 2] ;
X = [4, 1, 2, 3] ;
X = [1, 2, 3, 4] ;
X = [2, 3, 4, 1] ;
X = [3, 4, 1, 2] ;
X = [4, 1, 2, 3] ;
X = [1, 2, 3, 4] ;
X = [2, 3, 4, 1] ;
X = [3, 4, 1, 2] ;
X = [4, 1, 2, 3] 
......