Class SubSchema

Class Documentation

class SubSchema

A proxy type for name lookups in a Schema.

Elements of schema names are assumed to be separated by underscores (“a_b_c”); an incomplete lookup is one that does not resolve to a field. Not that even complete lookups can have nested names; a Point field, for instance, has “x” and “y” nested names.

This proxy object is implicitly convertible to both the appropriate Key type and the appropriate Field type, if the name is a complete one, and supports additional find() operations for nested names.

SubSchema is implemented as a proxy that essentially calls Schema::find after concatenating strings. It does not provide any performance advantage over using Schema::find directly. It is also lazy, so looking up a name prefix that does not exist within the schema is not considered an error until the proxy is used.

Some examples: 

Schema schema(false);
Key<int> a_i = schema.addField<int>("a_i", "integer field");
Key< Point<double> > a_p = schema.addField< Point<double> >("a_p", "point field");

assert(schema["a_i"] == a_i);
SubSchema a = schema["a"];
assert(a["i"] == a_i);
Field<int> f_a_i = schema["a_i"];
assert(f_a_i.getDoc() == "integer field");
assert(schema["a_i"] == "a_i");
assert(schema.find("a_p_x") == a_p.getX());

Unnamed Group

std::string join(std::string const &a, std::string const &b) const

Join strings using the field delimiter appropriate for this Schema.

std::string join(std::string const &a, std::string const &b, std::string const &c) const
std::string join(std::string const &a, std::string const &b, std::string const &c, std::string const &d) const

Public Functions

template<typename T>
SchemaItem<T> find(std::string const &name) const

Find a nested SchemaItem by name.

template<typename F>
void findAndApply(std::string const &name, F &&func) const

Find a nested SchemaItem by name and run a functor on it.

Names corresponding to named subfields are not accepted. The given functor must have an overloaded function call operator that accepts any SchemaItem type (the same as a functor provided to apply or Schema::forEach).

template<typename F>
void apply(F &&func) const

Run functor on the SchemaItem represented by this SubSchema

The given functor must have an overloaded function call operator that accepts any SchemaItem type (the same as a functor provided to apply or Schema::forEach).

Exceptions

  • Throws: pex::exceptions::NotFoundError if the SubSchemas prefix does not correspond to the full name of a regular field (not a named subfield).

SubSchema operator[](std::string const &name) const

Return a nested proxy.

std::string const &getPrefix() const

Return the prefix that defines this SubSchema relative to its parent Schema.

std::set<std::string> getNames(bool topOnly = false) const

Return a set of nested names that start with the SubSchema’s prefix.

Returns an instance of Python’s builtin set in Python.

See

Schema::getNames

template<typename T>
operator Key<T>() const

Implicit conversion to the appropriate Key type.

Implicit conversion operators that are invoked via assignment cannot be translated to Python. Instead, the Python wrappers provide an equivalent asKey() method.

template<typename T>
operator Field<T>() const

Implicit conversion to the appropriate Key type.

Implicit conversion operators that are invoked via assignment cannot be translated to Python. Instead, the Python wrappers provide an equivalent asField() method.