比较函子列表和统一变量

Question

如何验证两个列表在任意给定的顺序中是否表示其变量之间的相同关系，然后统一相应的变量?

例如列表:

[#=(_G13544,_G13547+1),#=(_G13553,_G13554),#=(_G13559,2),#>(_G13559, _G13544)]

等价于:

[#>(_G13453,_G13430),#=(_G13409,_G13355),#=(_G13453,2),#=(_G13430,1+_G13370)]

因为两者都可以写成:

[A#>B,C#=D,A#=2,B#=E+1]

和变量的绑定方式如下:

_G13453 = _G13559                  # Equivalent to A
_G13430 = _G13544                  # Equivalent to B
_G13409 = _G13553                  # Equivalent to C 
_G13355 = _G13554                  # Equivalent to D
_G13370 = _G13547                  # Equivalent to E

函子是以下CLPFD操作符:

• 对称: #=/2, +/2, -/2, #//2;
• 不对称: #>/2, and #</2;
• 一元: abs/1

Answer 1

开始吧

'same relationship between their variables'(L1, L2, Vs) :-
    copy_term(L1, T1),
    copy_term(L2, T2),
    numbervars(T1, 0, N),
    numbervars(T2, 0, N),
    rel_pairs(T1, T2, [], Vs).
rel_pairs([], [], B, B).
rel_pairs(Xs, Ys, B0, B2) :-
    select(X, Xs, Xr),
    select(Y, Ys, Yr),
    assign(X, Y, B0, B1),
    rel_pairs(Xr, Yr, B1, B2).
assign(A#=B, C#=D, B0, B2) :-
    assign(A, C, B0, B1),
    assign(B, D, B1, B2)
    ;
    assign(A, D, B0, B1),
    assign(B, C, B1, B2).
assign(A#>B, C#>D, B0, B2) :-
    assign(A, C, B0, B1),
    assign(B, D, B1, B2).
assign(A+B, C+D,  B0, B2) :-
    assign(A, C, B0, B1),
    assign(B, D, B1, B2)
    ;
    assign(A, D, B0, B1),
    assign(B, C, B1, B2).
assign('$VAR'(A), '$VAR'(B),  B0, B0) :-
    memberchk(A-B, B0), !.
assign('$VAR'(A), '$VAR'(B),  B0, [A-B|B0]) :-
    +memberchk(A-_, B0),
    +memberchk(_-B, B0), !.
assign(X, X, B, B).