SafeBool< T > Class Template Reference

#include <evo/type.h>

Detailed Description

template<class T>
class evo::SafeBool< T >

Safe bool base class.

This implements "safe" boolean evaluation, without the side-effects of implicit conversions from the bool type.

• Use by deriving the intended class from SafeBool
• The deriving class must implement the logical negation operator (as const) for boolean evaluation

  bool operator!() const

• Safe bool comparisons (obj1 == obj2 or obj1 != obj1 ) will not compile unless the deriving class implements operator==() or operator!=(), respectively
• No virtual methods are used even though this is a base class

Template Parameters

T	The deriving type being used.

Example:

#include <evo/type.h>

// Class supporting "safe bool evaluation"
struct Foo : public evo::SafeBool<Foo> {
    bool operator!() const
        { return false; }
};

void func() {
    const Foo foo;

    // Safe bool evaluation -- calls !operator!()
    if (foo) {
        // ...
    }

    // Negative bool evaluation -- calls operator!()
    if (!foo) {
        // ...
    }
}

Public Member Functions
	SafeBool ()
	Constructor. More...
	operator SafeBoolType () const
	Safe (explicit) evaluation as bool type. More...

Constructor & Destructor Documentation

SafeBool()

SafeBool ( )

inline

Constructor.

Member Function Documentation

operator SafeBoolType()

operator SafeBoolType ( ) const

inline

Safe (explicit) evaluation as bool type.

• This is called when object is directly evaluated as a bool, and is equivalent to: !operator!()
• See SafeBool

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The documentation for this class was generated from the following file:

• evo/type.h