Purpose of this document is to define how boost::optional is used in unified way throughout the code.

Boost Optional usage.cpp

/**
 * RULES
 * 1. Prefer using is_initialized() for checking the contents if the
 *    value is not assigned to a boost::optional right before
 * 2. Prefer get() over 'operator ->', to make visible what's happening
 * 3. Use get_value_or() if applicable, this makes the control flow less complex
 * 4. Optionally prefix variable with 'opt' or postfix with 'Optional'
 * 
 * DOCS http://www.boost.org/doc/libs/1_55_0/libs/optional/doc/html/index.html
 * 
 * Visual Assist X automatically converts dot (.) to '->' if such operator exists. Use BACKSPACE to
 * undo this change or disable feature from 'Vissual Assist X options / Advanced / Corrections'.
 */

// Example 1 - OK - 'is_initialized' indicates it's a boost::optional
const auto PolymeshData = MaybeGetPolymeshData();
if(PolymeshData.is_initialized()) {
    const Polymesh_t &Polymesh = PolymeshData.get();
    const auto Extrema = Polymesh.GetExtrema();
    // …
}
else  {
    // log an error
}

// Example 2 - OK - it is obvious that this is a boost::optional
const boost::optional<Polymesh_t> PolymeshData = GetPolymeshData();
if(PolymeshData)
{
    const auto Extrema = PolymeshData.get().GetExtrema();
}

// Example 3 - OK if the algorithm can work with an empty or default values
const boost::optional<Polymesh_t> PolymeshData = GetPolymeshData();
const Polymesh_t &Polymesh = PolymeshData.get_value_or(GetEmptyPolymesh());
const auto Extrema = PolymeshData.get().GetExtrema();

// Example 4 - NOT OK - Hides the boost::optional completely from user
const auto PolymeshData = GetPolymeshData();
if(PolymeshData)
{
    const auto Extrema = PolymeshData->GetExtrema();
}