NAME

SYNOPSIS

#include <keyval.h>

Inherits sc::KeyVal.

Detailed Description

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"))
   {}
};

can be used to read ParsedKeyVal input that looks like

b<B>: (
  f1 = 1.0
  a<A>: (
    f0 = 2.0
  )
)

Member Function Documentation

Author