[英]Creating a list of lists in Prolog
我想要一个带有约束的列表列表,这是我用SWI-Prolog编写的代码:
List = [L1,L2,L3],
L1 = [X1, X2], L1 ins 1..4,
L2 = [Y1, Y2], L2 ins 1..4,
L3 = [Z1, Z2], L3 ins 1..4.
但是,它给出了ERROR:Type Error: integer expected
。
在SWI-Prolog 7.1.11中使用库CLP(FD),我得到:
?- use_module(library(clpfd)).
% library(pairs) compiled into pairs 0.00 sec, 22 clauses
% library(lists) compiled into lists 0.01 sec, 122 clauses
% library(occurs) compiled into occurs 0.00 sec, 14 clauses
% library(apply_macros) compiled into apply_macros 0.02 sec, 175 clauses
% library(assoc) compiled into assoc 0.01 sec, 103 clauses
% library(clpfd) compiled into clpfd 0.18 sec, 2,848 clauses
true.
?- List = [L1,L2,L3],
L1 = [X1, X2], L1 ins 1..4,
L2 = [Y1, Y2], L2 ins 1..4,
L3 = [Z1, Z2], L3 ins 1..4.
List = [[X1, X2], [Y1, Y2], [Z1, Z2]],
L1 = [X1, X2],
L2 = [Y1, Y2],
L3 = [Z1, Z2],
X1 in 1..4,
X2 in 1..4,
Y1 in 1..4,
Y2 in 1..4,
Z1 in 1..4,
Z2 in 1..4.
也许错误是由于第一行末尾的点而不是逗号引起的(现在已更正)?
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