本文整理汇总了C++中Relation::back方法的典型用法代码示例。如果您正苦于以下问题：C++ Relation::back方法的具体用法？C++ Relation::back怎么用？C++ Relation::back使用的例子？那么恭喜您, 这里精选的方法代码示例或许可以为您提供帮助。您也可以进一步了解该方法所在类Relation的用法示例。
在下文中一共展示了Relation::back方法的1个代码示例，这些例子默认根据受欢迎程度排序。您可以为喜欢或者感觉有用的代码点赞，您的评价将有助于系统推荐出更棒的C++代码示例。
示例1: special
bool special(Condition &condition, Relation &intermediate, Relation &filtered) {
if (condition.type != ATOMIC) {
return false;
}
switch (condition.get.atom.type) {
case ATOM:
case MEMBERSHIP:
case SUBCLASS:
case FRAME:
return false;
case EQUALITY: {
Term *lhs = &(condition.get.atom.get.sides[0]);
Term *rhs = &(condition.get.atom.get.sides[1]);
if (lhs->type == VARIABLE && rhs->type == CONSTANT) {
swap(lhs, rhs);
}
if (rhs->type == CONSTANT) {
if (lhs->get.constant != rhs->get.constant) {
Relation empty;
filtered.swap(empty);
} else {
filtered = intermediate;
}
} else if (lhs->type == CONSTANT) {
Relation result;
Relation::iterator it = intermediate.begin();
for (; it != intermediate.end(); ++it) {
if (it->size() <= rhs->get.variable) {
it->resize(rhs->get.variable + 1);
}
if (it->at(rhs->get.variable) == 0) {
result.push_back(*it);
Tuple &t = result.back();
t[rhs->get.variable] = lhs->get.constant;
} else if (it->at(rhs->get.variable) == lhs->get.constant) {
result.push_back(*it);
}
}
filtered.swap(result);
} else {
varint_t maxvar = max(lhs->get.variable, rhs->get.variable);
Relation result;
Relation::iterator it = intermediate.begin();
for (; it != intermediate.end(); ++it) {
if (it->size() <= maxvar) {
it->resize(maxvar + 1);
}
constint_t c1 = it->at(lhs->get.variable);
constint_t c2 = it->at(rhs->get.variable);
if (c1 == 0 && c2 == 0) {
cerr << "[ERROR] Please make sure equality statements occur to the right of atomic formulas that bind a variable." << endl;
return true;
}
if (c1 == 0) {
result.push_back(*it);
Tuple &t = result.back();
t[lhs->get.variable] = c2;
} else if (c2 == 0) {
result.push_back(*it);
Tuple &t = result.back();
t[rhs->get.variable] = c1;
} else if (c1 == c2) {
result.push_back(*it);
}
}
filtered.swap(result);
}
return true;
}
case EXTERNAL: {
break; // just handle outside the messy switch statement
}
default: {
cerr << "[ERROR] Unhandled case " << (int)condition.get.atom.type << " at line " << __LINE__ << endl;
return false;
}
}
///// HANDLE BUILTIN (EXTERNAL) /////
Builtin &builtin = condition.get.atom.get.builtin;
switch (builtin.predicate) {
case BUILTIN_PRED_LIST_CONTAINS: {
if (builtin.arguments.end - builtin.arguments.begin != 2) {
cerr << "[ERROR] Invalid use of list contains builtin, which should have exactly two arguments, but instead found " << builtin << endl;
return false;
}
Term *arg1 = builtin.arguments.begin;
Term *arg2 = arg1 + 1;
if (arg1->type != LIST) {
cerr << "[ERROR] First argument of list contains builtin must be a list, but instead found " << *arg1 << endl;
return false;
}
switch (arg2->type) {
case FUNCTION:
cerr << "[ERROR] Functions not supported." << endl;
return false;
case LIST:
cerr << "[ERROR] Currently not supporting nested lists." << endl;
return false;
case CONSTANT: {
//.........这里部分代码省略.........