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Added default parameters for the as<> function (new API)

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This commit is contained in:
Jesse Beder
2012-01-12 01:03:31 -06:00
parent ddc578dbd7
commit d1e4c2640c
3 changed files with 81 additions and 15 deletions
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81
include/yaml-cpp/node/impl.h
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@@ -65,26 +65,77 @@ namespace YAML
}
// access
// template helpers
template<typename T, typename S>
struct as_if {
explicit as_if(const Node& node_): node(node_) {}
const Node& node;
const T operator()(const S& fallback) const {
if(!node.m_pNode)
return fallback;
T t;
if(convert<T>::decode(node, t))
return t;
return fallback;
}
};
template<typename S>
struct as_if<std::string, S> {
explicit as_if(const Node& node_): node(node_) {}
const Node& node;
const std::string operator()(const S& fallback) const {
if(node.Type() != NodeType::Scalar)
return fallback;
return node.Scalar();
}
};
template<typename T>
struct as_if<T, void> {
explicit as_if(const Node& node_): node(node_) {}
const Node& node;
const T operator()() const {
if(!node.m_pNode)
throw std::runtime_error("Unable to convert to type");
T t;
if(convert<T>::decode(node, t))
return t;
throw std::runtime_error("Unable to convert to type");
}
};
template<>
struct as_if<std::string, void> {
explicit as_if(const Node& node_): node(node_) {}
const Node& node;
const std::string operator()() const {
if(node.Type() != NodeType::Scalar)
throw std::runtime_error("Unable to convert to string, not a scalar");
return node.Scalar();
}
};
// access functions
template<typename T>
inline const T Node::as() const
{
if(!m_pNode)
throw std::runtime_error("Unable to convert to type");
T t;
if(convert<T>::decode(*this, t))
return t;
throw std::runtime_error("Unable to convert to type");
}
template<>
inline const std::string Node::as() const
{
if(Type() != NodeType::Scalar)
throw std::runtime_error("Unable to convert to string, not a scalar");
return Scalar();
return as_if<T, void>(*this)();
}
template<typename T, typename S>
inline const T Node::as(const S& fallback) const
{
return as_if<T, S>(*this)(fallback);
}
inline const std::string& Node::Scalar() const
{
return m_pNode ? m_pNode->scalar() : detail::node_data::empty_scalar;