#include <keyval.h>
Inheritance diagram for sc::PrefixKeyVal:
Public Member Functions | |
void | errortrace (std::ostream &fp=ExEnv::err0()) |
Write a message to fp describing the error. | |
void | dump (std::ostream &fp=ExEnv::err0()) |
Write a message to fp describing the error. | |
Constructors. | |
Construct a PrefixKeyVal, using the given prefix and indices. | |
PrefixKeyVal (const Ref< KeyVal > &, int i) | |
PrefixKeyVal (const Ref< KeyVal > &, int i, int j) | |
PrefixKeyVal (const Ref< KeyVal > &, int i, int j, int k) | |
PrefixKeyVal (const Ref< KeyVal > &, int i, int j, int k, int l) | |
PrefixKeyVal (const Ref< KeyVal > &, const char *prefix) | |
PrefixKeyVal (const Ref< KeyVal > &, const char *prefix, int i) | |
PrefixKeyVal (const Ref< KeyVal > &, const char *prefix, int i, int j) | |
PrefixKeyVal (const Ref< KeyVal > &, const char *prefix, int i, int j, int k) | |
PrefixKeyVal (const Ref< KeyVal > &, const char *prefix, int i, int j, int k, int l) |
This is convenient for reading keys grouped together with a common prefix. Consider the following code:
sc::Ref<sc::KeyVal> keyval = new sc::PrefixKeyVal("A",original_keyval); int r = keyval->intvalue("x");This code will assign to r the value associated with "x" in keyval. keyval will search for "x" by searching for "A::x" in original_keyval.
This class is important for implementing constructors that take KeyVal arguments. When an object is being constructed from a KeyVal, it may contain another object that must be constructed from a KeyVal. In order to let the sub-object read the correct keywords from the KeyVal, without knowledge of the containing objects keyword prefix, a PrefixKeyVal can be constructed. For example, the code
class A: public DescribedClass { double f0_; public: A(const Ref<KeyVal> &keyval): f0_(keyval->doublevalue("f0")) {} } class B: public DescribedClass { double f1_; Ref<A> a_; public: B(const Ref<KeyVal> &keyval): f1_(keyval->doublevalue("f1")), a_(new PrefixKeyVal(keyval,"a")) {} };
b<B>: ( f1 = 1.0 a<A>: ( f0 = 2.0 ) )