Struct template call_if_statement<true, Then, ThenResult>

boost::contract::call_if_statement<true, Then, ThenResult> — Template specialization to handle static predicates that are true for then-branch functor template calls that do not return void.

Synopsis

// In header: <boost/contract/call_if.hpp>

template<typename Then, typename ThenResult> 
struct call_if_statement<true, Then, ThenResult> {
  // construct/copy/destruct
  explicit call_if_statement(Then);

  // public member functions
  operator ThenResult() const;
  template<typename Else> ThenResult else_(Else const &) const;
  template<bool ElseIfPred, typename ElseIfThen> 
    call_if_statement< true, Then, ThenResult > 
    else_if_c(ElseIfThen const &) const;
  template<typename ElseIfPred, typename ElseIfThen> 
    call_if_statement< true, Then, ThenResult > 
    else_if(ElseIfThen const &) const;
};

Description

Usually this class template is instantiated only via the return value of boost::contract::call_if and boost::contract::call_if_c.

See Also:

Assertion Requirements

Template Parameters

```
typename Then
```
Type of functor template to call when the static predicate is true (as it is for this template specialization).
```
typename ThenResult
```
Non-void return type of the then-branch functor template call.

`call_if_statement` public construct/copy/destruct

explicit call_if_statement(Then f);

Construct this object with the then-branch functor template.

Parameters:

`f`	Then-branch nullary functor template. The functor template call `f()` is actually compiled and executed for this template specialization (because the if-statement static predicate is `true`). The return type of `f()` must be the same as (or implicitly convertible to) the `ThenResult` type.

`call_if_statement` public member functions

```
operator ThenResult() const;
```
This implicit type conversion returns a copy of the value returned by the call to the then-branch functor template.

template<typename Else> ThenResult else_(Else const & f) const;

Specify the else-branch functor template.

Parameters:

`f`	Else-branch nullary functor template. The functor template call `f()` is never compiled and executed for this template specialization (because the if-statement static predicate is `true`). The return type of `f()` must be the same as (or implicitly convertible to) the `ThenResult` type.

Returns:

A copy of the value returned by the call to the then-branch functor template (because the else-branch functor template call is not executed).

template<bool ElseIfPred, typename ElseIfThen> 
  call_if_statement< true, Then, ThenResult > 
  else_if_c(ElseIfThen const & f) const;

Specify an else-if-branch functor template (using a static boolean predicate).

Parameters:

`f`	Else-if-branch nullary functor template. The functor template call `f()` is never compiled and executed for this template specialization (because the if-statement static predicate is `true`). The return type of `f()` must be the same as (or implicitly convertible to) the `ThenResult` type.

Template Parameters:

ElseIfPred

Static boolean predicate selecting which functor template call to compile and execute.

Returns:

A call-if statement so the else statement and additional else-if statements can be specified if needed. Eventually, it will be the return value of the then-branch functor template call for this template specialization (because the if-statement static predicate is true).

template<typename ElseIfPred, typename ElseIfThen> 
  call_if_statement< true, Then, ThenResult > 
  else_if(ElseIfThen const & f) const;

Specify an else-if-branch functor template (using a nullary boolean meta-function).

Parameters:

`f`	Else-if-branch nullary functor template. The functor template call `f()` is never compiled and executed for this template specialization (because the if-statement static predicate is `true`). The return type of `f()` must be the same as (or implicitly convertible to) the `ThenResult` type.

Template Parameters:

ElseIfPred

Nullary boolean meta-function selecting which functor template call to compile and execute.

Returns:

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